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Engine Noise Diagnosis
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Reparaturen Tips
| A/C
NEWS & UPDATES |
April/May1999
|
THIS
EDITION brings you service tips and UPDATES that you
will want to keep as reference.
EVAPORATOR ODOR ... PHEW !
Evaporator odors have been around for years. There can
be several odors in a cooled airflow:
(1) "Dirty socks" odor from airborne fungus is
organic material and is called an ORGANIC ODOR.
(2) "Refrigerator" odor emitted by the
anti-corrosion coating on the evaporator. Noticeable
when the system is running very cold. This is a CHEMICAL
ODOR. (
3) "Cement" or dusty room odor comes from the
evaporators. High performance evaps use thin alloys with
high fin counts which traps water on the evap face
causing the anti-corrosion coating to come off and breed
the fungus.
Airmec sells several aerosol sprays that neutralize the
fungus growth. In some cases the evap case will have to
be opened and the evap replaced.
HOW
DOES AUTO A/C WORK ?
Everything has a certain amount of heat except at
absolute zero ( -460 degrees. F ). An ice cube may feel
cool to the touch, but actually it just has less heat
than your hand. That means heat is transferring from
your hand to the ice cube. This is the principle behind
how an A/C cools the air in a car. Heated air is forced
across a cold evaporator and is transferred to the
refrigerant gas, making the air less hot. The
refrigerant carries the heat away from the evaporator to
the compressor. The refrigerant is super heated by
compression and is forced through the condenser where
cooler outside air takes the heat from the refrigerant.
Its next stop is the expansion device (TXV or CCOT)
which meters refrigerant into the evap and we start over
again. SIMPLE ISN'T IT !
WHAT DOES A DRIER - DRY?
IT'S NOT THE FREON!! It's the oil in the refrigerant
that absorbs moisture and holds debris in the system.
Replacing the drier / accumulator, in addition to
evacuation, will assure better performance. Be sure your
new drier/accumulator has the new XH7 or XH9 desiccant
that is recommended for all refrigerants.
WHY
INSIST ON FLUSHING
there is no way to know how much oil is in a system
(1) Flushing eliminates excess oil from previous
services You do not want to add another full charge of
oil when replacing a compressor and adding oil to the
system.
(2) Sludge and debris, left in the system, clogs the
orifice tube/expansion valve and can damage the valves
in a compressor.
RETROFIT - NOW OR LATER?
Currently, there is no law or regulation stating
that a vehicle must be converted to refrigerant R134a.
However, the R12 supply is running out, so if a major
repair is required on a R12 system it is in the
customers' best interest to convert to the R134a
refrigerant.
COMPRESSOR CLUTCH FAILURE
Common causes for clutch failure:
1. Bearing failure: re-packed bearings have a short
life. Don't use them - ITS YOUR LABOR
2. Air Gap: between the outer plate (shoe) and the
belt/rotor. About .025 inch is good
3. Shorted Coil: Correct coil resistance 2 - 4 ohms.
4. Locked Compressor: excessive discharge pressure Check
for restricted condensers, receiver/driers or an over
charge of oil.
COMPRESSORS
NEW-REBUILT- REMAN NEW
compressors are pricey and may cause you to loose the
repair job. REBUILDERS tend to reuse worn internal
parts, seals, O-rings and repacked clutch bearings.
REMANUFACTURED compressors cost more because they use
new bearings, seals, O-rings and piston rings. Airmec,
as a parts supplier, has made numerous extra deliveries
to replace defective rebuilt compressors. With the cost
of labor, yours and ours, this expense is unacceptable. USE
REMANS.
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| A/C NEWS & UPDATES |
July/August1999
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Black Death !
Ford FS10/FX15 compressor failure causes a black residue that is
actually a combination of solder flux from the condenser and
aluminum shavings from the old compressor. When this goo cools
it hardens at the bottom of the condenser. Repeated flushing
will not remove it, however, when the system is charged and
running it liquefies and flows out of the condenser and into the
liquid line clogging the orifice tube. With no refrigerant
flowing, past the orifice tube, the compressor is starved of
lubricant and will lock up. The only answer is to replace the
condenser.
REFRIG. LEAKS - Find
the small ones! At one time a ½ lb. leak /year was acceptable
in a 4-5 lb. system and freon was 80 cents/lb. Today systems are
much smaller and ½ oz makes a big difference in performance.
Most system leaks will show up under static conditions, with a
good halogen leak detector, however some leak only when the
system is in operation. This is where the insertion of a
florescent dye helps find the leak. Most car manufactures
approve the use of trace dyes. Ford & Chrysler have been
installing dyes, on the assembly line, for several years. Dye
can be inserted at the time of charging or when the system is
fully charged. The amount of dye used is less than ½ oz and
remains in the system even if the total charge is lost. Since
the dye stains the oil, not the freon, only flushing will remove
it. Note, dye can only be seen with an UV lamp and the leak has
to be where the light can reach it.
WHERE
DOES THE MOISTURE GO?
Moisture in an A/C system combines with the lubricant and is not
easily removed with simple evacuation. A vacuum pumps
effectiveness varies with its age and any restrictions in the
inlet hoses. Replacement of the Accumulator or Drier and the
lubricant is the best solution to a system that has been left
open to the atmosphere.
WHY
AN EXACT AMOUNT OF FREON?
You don't know how much freon is in a system so you should
recover the old freon and evacuate the system before charging.
Systems today take odd amounts of freon. No longer is it 2 or 3
lbs, but rather 1.8, 2.6 lbs or some odd amount. With compressor
tolerances so tight and the lubricant mixing with the freon, the
mixture must be just right so as to be a mist when it enters the
compressor. The wrong mixture will cause compressor failure.
CHARGING WITH LIQUID INSTEAD OF GAS
Sometimes you get by with doing it, but more often you will
freeze and then shatter the compressors valves.
MORE ON CLUTCH FAILURE
Common causes for clutch failure: The clutch is like a fuse for
the system, protecting compressor internal parts
1. Bearing failure: Use of re-packed bearings
2. Air Gap: Between the shoe and the belt/rotor.
3. Shorted Coil: Correct coil resistance 2 - 4 ohms.
4. Locked Compressor: excessive discharge pressure Check for
restricted condensers, receiver/driers or an over charge of oil.
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There are several potential dangers when jump
starting a vehicle. Battery
explosion, computer and/or component damage can result from
improper starting procedures. Arcing, sparks and voltage spikes of any
kind must be avoided or minimized.
Before starting, you need to determine if you should
even attempt to jump start the vehicle. If the battery is severely
discharged or dead, I recommend NOT to jump start the vehicle.
This is because charging a dead battery should be done by a battery
charger and not an alternator! In this case, when the vehicle is
started, the alternators' voltage regulator will put it into full output
mode. Since the battery is dead, it would take a long time for the
alternator to charge it up. It is very possible for the alternator to
burn itself up in the process. This is especially likely on Ford
vehicles with an IAR alternator (used on vehicles produced between
1986-1993). In the extreme cases, like the Ford IAR alternator, a
vehicle FIRE is quite possible.
Make sure the Ignition switch and all accessory switches are off
on both vehicles. Put the transmission selector lever in park (for A/T
vehicles) or neutral (for M/T vehicles). Set the emergency brake. Be
sure the vehicles are separated and not touching one another to
avoid sparks when connecting the jumper cables. Most automotive systems
have a negative ground, but be sure both do before proceeding.
Make the connections as follows:
1. Connect jumper to the (+) post of the discharged
battery.
2. Connect the other end of the same jumper cable to the (+) post of
the charged battery.
3. Connect the other jumper cable to the (-) post of the charged
battery.
4. Connect the remaining jumper cable end to the engine block or frame
of the vehicle being jumped. Make this connection as far from the
discharged battery as possible.
5. Turn on the Ignition in the disabled car and then attempt to start
it for no more than 10 seconds. If the engine doesn't run, allow the
cables to cool for 25 second before trying again. Start the booster
car so the alternator can prevent excessive load on its battery. If
the engine doesn't start after three tries, STOP. More than 30
second of cranking seldom starts an engine unless some mechanical
adjustment is made.
6. After the disabled car has started, allow the engine to return to
idle. Then remove the cables in reverse order; Start with the negative
cable on the engine block. Avoid touching the cable clamps together or
to other metal while the cables are attached to the terminals.
CAUTION:
Under most circumstances, it is not necessary to start the booster car.
If you do, before disconnecting the cables, make sure to either
1. Turn off the booster car, or
2. Turn on the blower motor (high) and the headlights. and let the
booster car run with these on for at least 5 second. Failure to do so
will result in a high voltage spike being sent into the booster cars'
electrical system, which could result in computer or component damage.
All-Wheel Drive Astro/Safari Van Idler Arms
The original equipment idler arms on General Motors Astro
and Safari all-wheel drive vans in
some cases can develop loosness at very low mileage. The
looseness can contribute to premature tire wear. Moog's
problem solving K6392 idler arm uses our proven powdered
metal bearings and Belleville washer design along with a
torque-controlled telescopic spacer to prevent steering
looseness. The K6392 fits both sides of this dual idler arm
steering linkage
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A Problem With Pulsation?
Pedal Pulsation is one of the more frequently
occurring problems appearing in shops today. Due to the advent
of front wheel drive; technicians commonly address the problem
by turning the rotors. This solves the pulsation, but doesn't
address the cause of the pulsation. This is evident when the
customer comes back in a few weeks complaining of the same
problem. Excessive system run-out will cause a rotor to wear out
of parallel ( thickness variation ).
Brake rotor thickness variation causes brake
vibration due to changes in the braking force as thick and thin
portions of the rotor pass between the pads. Eric Smith, Senior
Instructor for Wagner Brake at the Moog World Training Center in
St. Louis, says technicians sometimes pin the blame on a
defective rotor, but often it's due to excessive system
run-out, which has not been checked by the technician.
Smith says the run-out will cause the rotor to
wear itself out of parallel, and is why turning or replacing the
rotor won't solve the problem. System run-out can be caused by
poor mating of fanges between the hub and rotor when assembled
as a unit ( by excessive rust, preventing a clean fit of the
rotor on the flange), excessive run-out and even improper
torquing of the wheel bolts.
Once the rotor heats up during
operation, if one lug is a little less tight that the others,
the rotor will expand at that point and cause run-out,
says Smith. Compounding this is the fact that the brake might
only have run-out when the rotor is hot. When the customer takes
the car back to the shop, it's cooled when checked by the
technician and by that time the run-out disappears. If not
corrected, though, it will eventually have a permanent run-out,
and be worn out of parallel.
Make sure rotor run-out is below
specifications before reinstallation; also make sure the
hub is clean and rust free before installing the rotor.
System run-out should be checked after installing the rotor (new
or turned). If run-out is above spec, the solution may be as
easy as re-indexing the rotor one stud at a time, until run-out
is within spec. It may also be necessary to replace the hub
assembly.
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HOW TO PREVENT HEAD GASKET FAILURES CAUSED BY
ENGINE OVERHEATING
WHEN AN ENGINE OVERHEATS
Engines are designed to operate within a "normal"
temperature range of about 190 to 220 degrees F. A relatively
consistent operating temperature is absolutely essential for
proper emissions control, good fuel economy and performance.
If the engine overheats and exceeds its normal operating range,
the elevated temperatures can cause extreme stress in the
cylinder head which may result in a head gasket failure. This is
especially true with aluminum cylinder heads because aluminum
expands about two to three times as much as cast iron when it
gets hot. The difference in thermal expansion rates between an
aluminum head and cast iron block combined with the added stress
caused by overheating can cause the head to warp. This, in turn,
may lead to a loss of clamping force in critical areas and allow
the head gasket to leak.
What else can happen when an engine overheats? Coolant can boil
out of the radiator and be lost. Pistons swell inside their
cylinders and can scuff or seize. Valve stems can swell in their
guides and also scuff or seize. This, in turn, may damage valve
train components (broken rocker arms, bent pushrods, etc.) or
possibly result in damaging contact between the valve head and
piston if the valve sticks open. Valve lifters can also stick,
possibly causing a valve to remain open a little too long.
Bearings can seize. Cylinder heads can crack (especially if
someone dumps cold water into the radiator in an attempt to
"cool off" the engine). Combustion chambers can become
so hot that a spark is no longer needed to ignite the fuel,
leading to a condition known as "preignition" where
the engine misfires and runs erratically. Air/fuel mixtures are
upset, and gasoline becomes less able to resist detonation. Oil
thins out and is less able to protect the engine's internal
components against friction and wear.
IF AN ENGINE HAS OVERHEATED...
If a head gasket has failed as a result of severe engine
overheating, both the face of the cylinder head and block deck
should be checked for war page -- and resurfaced if needed to
restore flatness prior to replacing the head gasket. If the face
of the head and/or block deck are not flat and are not
resurfaced when the head gasket is replaced, the new head gasket
will be unevenly loaded and will likely leak or fail.
Flatness can be checked by placing a straight edge on the face
of the cylinder head or block, and then using a feeler gauge to
check any gaps between the straight edge and head or block. If
the amount of war page exceeds the following maximum limits, the
head or block is not flat enough to hold a good seal against the
head gasket and should be resurfaced:
Maximum out of flat:
Length Width
3 cylinder and V6 engines .003 in. .002 in.
4 cylinder and V8 engines .004 in. .002 in.
Straight 6 cylinder engines .006 in. .002 in.
The surface finish on the face of the head and block is also
important. The surface finish should be 54 to 113 RA micro
inches (60 to 125 RMS), with a recommended range of 80 to 100 RA
(90 to 110 RMS).
If the surface is too rough (more than 113 RA), it may be too
rough to seal properly and the head gasket will leak. If the
surface is too smooth (less than 54 RA), it may not provide
enough "grip" to prevent the gasket from flowing or
scrubbing.
WHAT CAUSES OVERHEATING?
Overheating can be caused by anything that decreases the cooling
system's ability to absorb, transport and dissipate heat: A low
coolant level, loss of coolant (through internal or external
leaks), poor heat conductivity inside the engine because of
accumulated deposits in the water jackets, a defective
thermostat that doesn't open, poor airflow through the radiator,
a slipping fan clutch, an inoperative electric cooling fan, a
collapsed lower radiator hose, an eroded or loose water pump
impeller, or even a defective radiator cap.
One of nature's basic laws says that heat always flows from an
area of higher temperature to an area of lesser temperature,
never the other way around. The only way to cool hot metal,
therefore, is to keep it in constant contact with a cooler
liquid. And the only way to do that is to keep the coolant in
constant circulation. As soon as the circulation stops, either
because of a problem with the water pump, thermostat or loss of
coolant, temperatures begin to rise and the engine starts to
overheat.
>The coolant also has to get rid of the heat it soaks up
while passing through the block and head(s). So the radiator
must be capable of doing its job, which requires the help of an
efficient cooling fan at slow speeds. Finally, the thermostat
must be doing its job to keep the engine's average temperature
within the normal range. If the thermostat fails to open, it
will effectively block the flow of coolant and the engine will
overheat.
WHAT TO CHECKIf your engine overheated
and the cause hasn't been determined, all of the following
should be checked to make sure the engine doesn't overheat
again:
Thermostat
Severe overheating can often damage a good thermostat.
Therefore, if the engine has overheated because of another
problem, the thermostat should be tested or replaced before the
engine is returned to service.
One way to check the thermostat is to start the engine and feel
the upper radiator hose. The hose should not feel uncomfortably
hot until the engine has warmed-up and the thermostat opens. If
the hose does not get hot, it means the thermostat is not
opening.
Another way to test the thermostat is to remove it and dip it
into a pan of boiling water (it should open). The exact opening
temperature can be checked by using a thermometer.
If the thermostat needs to be replaced, install one with the
same temperature rating as the original. Most cars and light
trucks since 1971 require thermostats with 192 or 195 degree
ratings. Using a cooler thermostat (160 or 180 degree) can
increase fuel and oil consumption, ring wear and emissions. On
newer vehicles with computerized engine controls, the wrong
thermostat can cause major performance and emission problems if
the engine fails to reach the proper operating temperature.
Cooling system leaks
Loss of coolant because of a leak is probably the most common
cause of overheating. Possible leak points include hoses, the
radiator, heater core, water pump, thermostat housing, head
gasket, freeze plugs, automatic transmission oil cooler,
cylinder head(s) and block.
Make a careful visual inspection of the entire cooling system,
and then pressure test the cooling system and radiator cap. A
pressure test will reveal internal leaks such as seepage past
the head gasket (usually due to war page in the head or block,
too rough a surface finish on the head or block, or improperly
torqued head bolts) as well as cracks in the head(s) or engine
block. If there are no leaks, the system should hold pressure
for at least a minute or more.
It's important to pressure test the radiator cap too, because a
weak cap (or one with a pressure rating too low for the
application) can allow coolant to escape from the radiator.
Fan
With mechanical fans, most overheating problems are caused by a
faulty fan clutch -- though a missing fan shroud can reduce the
fan's cooling effectiveness by as much as 50% (depending on the
fan's distance from the radiator) which may be enough to cause
the engine to overheat in hot weather or when working hard.
The fan clutch disengages the fan when less cooling is needed to
reduce the parasitic horsepower drain on the engine as well as
fan noise. Inside the clutch is a special silicone fluid that
acts like a fluid coupling to turn the fan. Above a certain
r.p.m., the resistance created by the fan exceeds the shear
characteristics of the fluid and the fan ceases to spin any
faster. "Thermal" fan clutches also have a bimetal
thermostat spring on the front that increases or decreases the
amount of slippage depending on the temperature of the air
flowing through the radiator. This allows more or less cooling
as needed.
Defective fan clutches are a common and often overlooked cause
of overheating. The shear characteristics of the clutch fluid
gradually deteriorates over time, with an average loss in drive
efficiency of about 200 r.p.m. per year. Eventually, slippage
reaches the point where effective cooling is no longer possible
and overheating results. (On average, the life of a fan clutch
is about the same as a water pump. If one needs to be replaced,
the other usually does too.)
If the fan clutch shows signs of fluid leakage (oily streaks
radiating outward from the hub of the clutch), spins freely with
little or no resistance when the engine is off, or wobbles when
the fan is pushed in or out, it needs to be replaced.
With an electric cooling fan, check to see that the fan cycles
on when the engine gets hot and when the air conditioner is on.
If the fan fails to come on, check the fan motor wiring
connections, relay and temperature sensor.
Try jumping the fan directly to the battery. It it runs, the
problem is in the wiring, relay or sensor. If it fails to run,
the fan motor is bad and needs to be replaced.
Water pump
Any wobble in the pump shaft or seepage would call for
replacement. In some instances, a pump can cause an engine to
overheat if the impeller vanes are badly eroded due to corrosion
or if the impeller has come loose from the shaft. The wrong pump
may also cause an engine to overheat. Some engines with
serpentine drive belts require a special water pump that turns
in the opposite direction of those used on the same engine with
ordinary V-belts.
Belts & hoses
Check belt tension and condition. A loose belt that slips may
prevent the water pump from circulating coolant fast enough
and/or the fan from turning fast for proper cooling.
The condition of the hoses should also be checked. Though not
leaking now, internal corrosion or old age may make them
vulnerable to sudden failure. Radiator and heater hoses should
be replaced if leaking, cracked, brittle, mushy feeling or
otherwise damaged. Make sure the clamps are tight, too.
Sometimes a lower radiator hose will collapse under vacuum at
high speed and restrict the flow of coolant from the radiator
into the engine. This can happen if the reinforcing spring
inside the hose is missing or damaged.
Radiator
The most common problems radiators fall prey to are clogging
(both internal and external) and leaks. Dirt, bugs and debris
can block air flow through the core and reduce the radiator's
ability to dissipate heat.
Internal corrosion and an accumulation of deposits can likewise
inhibit coolant circulation and reduce cooling. "Back
flushing" the radiator and cooling system when changing
coolant is highly recommended to dislodge accumulated deposits
and to flush the remaining coolant from the engine block. Back
flushing is running water back through the radiator and engine
in the opposite direction to which it normally flows. After the
coolant has been drained from the radiator, a T-fitting is
installed in the heater inlet hose. The fitting is then
connected to a pressurized water hose or power flusher. The
water is turned on and the system is reverse flushed. The
flushing should be continued until only clean water emerges from
the radiator. Cleaning chemicals may also be used to remove
accumulated deposits from the system.
When the cooling system is refilled, use a 50/50 mixture of
ethylene glycol antifreeze and water. This will give freezing
protection down to -34 degrees Fahrenheit, and boiling
protection to 265 degrees F. in a pressurized system with a 14
psi radiator cap. A 70/30 mixture will protect against freezing
down to -84 degrees F. and boil over up to 276 degrees F. Do not
use more than 70% a antifreeze because antifreeze carries heat
less efficiently than water. Straight water should never be used
in the cooling system because it offers no boil over or freezing
protection and no corrosion protection (which is extremely
important in today's bimetal and aluminum engines).
When refilling the cooling system, be sure you get it completely
full. Air pockets in the head's), heater core and below the
thermostat can interfere with proper coolant circulation and
cooling. Some cars (mostly front-wheel drive) may have one or
more "bleeder valves" for venting trapped air from the
cooling system. On some vehicles, it may be necessary to
temporarily loosen a heater hose to get all the air out of the
system.
Other factors that can contribute to overheating include
retarded ignition timing, detonation/preignition, a lean
air/fuel mixture, exhaust restrictions (partially plugged
converter or muffler), a radiator that's too small for the
engine, and overworking the engine (towing, mountain driving,
etc. in unusually hot weather).
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Welcome to the Gates Rubber Company
How to Detect a Bad Hose!
Give A Good Squeeze To Detect A Bad Hose
Until recently, the most common method of
checking coolant hose was to visually inspect its outside
cover for signs of wear, or "ballooning" under
pressure. This method is no longer considered completely
reliable in light of research by The Gates Rubber Company that
proves most hoses fail from the inside out.
The Enemy Within
What you can't see can hurt you. That's what
Gates engineers discovered during four years of field testing
on fleet vehicles. In these tests, they identified the primary
cause of coolant hose failure as an electrochemical attack on
the rubber tube compound in the hose.
The phenomenon is known as electrochemical
degradation, or ECD. It occurs because the hose, liquid
coolant (ethylene glycol antifreeze and water), and the
engine/radiator fittings form a galvanic cell or
"battery." This chemical reaction causes microcracks
in the hose tube, allowing the coolant to attack and weaken
the hose reinforcement.
The "Squeeze Test"
The best way to check coolant hose for the
effects of ECD is to squeeze the hose near the clamps or
connectors using the following procedure:
- Make sure the engine is cool.
- Use fingers and thumb to check for
weakness, not the whole hand.
- Squeeze near the connectors. ECD occurs
within two inches of the ends of the hose -- not in the
middle
- Check for any difference in the feel
between the middle and ends of the hose. "Gaps,"
or "channels," can be felt along the length of
the hose where it has been weakened by ECD.
- If the ends are soft and feel mushy,
chances are, the hose is under attack by ECD. To avoid
breakdown of the cooling system, Gates engineers recommend
replacing the hose immediately.
Solving The Problem
ECD is evident in almost all cooling system
hoses. The most severe damage occurs where the temperature is
hottest and air is present with the coolant, which is why
upper radiator hoses tend to fail first.
A replacement interval of four years for all
coolant carrying hoses -- especially the upper radiator,
bypass and heater hoses -- can help prevent unexpected failure
from ECD. The incidence of hose failure increases sharply
after four years for most vehicles.
Earlier hose replacement is recommended for
fleet vehicles such as taxis, police cars and delivery vans
that are subject to significant stop-and-go driving and the
resulting high engine and coolant temperatures.
To address the damage caused by ECD, Gates developed an
electrochemically-resistant coolant hose using a new EPDM
(ethylene propylene rubber) formulation and special wrapped
reinforcement. These new hoses are long-lasting with no ECD
effect.
In addition to providing electrochemical
resistance, the new EPDM hose offers improved performance
characteristics over both standard rubber hose and much more
expensive silicone hose.
In tough fleet tests, Gates hoses have gone
200,000 miles, and are still going, with no electrochemical
damage. Standard hoses revealed damage and failures as early
as 20,000 miles on the same fleet applications.
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Under the Hood
- Antifreeze/coolant
Checking the Coolant
Engines get hot in all kinds of weather. Engine
coolants keep them from overheating. To make sure that doesn't
happen, check the coolant level in your radiator every time you
check your oil. Like your oil, coolant should at least be checked
every 3,000 miles.
Here's how to check your coolant level
- Open the hood and find the radiator, which is
usually very close to the front of the car. The radiator coolant
reservoir is a plastic tank near radiator, usually off to one
side. Check the owner's manual, if you can't find it.
- Check to see if the coolant level is up to the
level indicated on the outside of the reservoir.
- If the level is low, remove the top of the
reservoir and add coolant. A funnel might help you keep from
spilling. Make sure you read the instructions on the coolant
container. Sometimes you'll need to add water to the coolant
before you pour it in.
- Very important: Don't try to remove the
radiator cap when the engine is hot. Always add coolant to the
plastic reservoir, not to the radiator itself.
- Belts
Inspect and Adjust Belts
Belts should be checked on a regular basis (about
once a month). In general, you should be on the look out for worn,
glazed or frayed belts. Many accessories including the alternator,
fan and coolant pump are operated by drive belts. If these belts
break or slip the components they drive will fail to work.
Here's how to inspect and replace a belt:
- Twist it so you can see the underside of the
"V" shape on V-type belts, or the ribs on a
serpentine-type belt. Cracks indicate the belt is getting
ready to fail. Oil-soaked belts can slip and not rotate the
component they are driving fast enough. Glazed belts have a
shiny appearance; this occurs when a belt is not tight enough
and the slipping polishes its surface. Torn or split belts have
major damage and must be replaced immediately.
- Before adjusting any drive belt, always check
the service manual for specific instructions. Find the longest
span in the belt and push on it as shown below. It should move
in about half an inch. If it moves more than this, the belt is
too loose. If it moves less, it is too tight.
- Most belts are adjusted by loosening the
support for the alternator and moving it back and forth to
tighten or loosen the belt. Other systems use an idler pulley
for the adjustment. A typical adjustment procedure is shown
below.
- First loosen the adjustment fastener on the
slotted alternator support. Wedge a pry bar between a strong
part of the engine and the alternator. Pull on the pry bar to
move the alternator housing in a direction to tighten the belt.
Tighten the adjustment fastener. Recheck the adjustment by
measuring the belt as explained earlier.
- When you have determined that a drive belt is
defective and needs to be replaced, you should have the
replacement belt on hand. Loosen the adjustment fastener on the
alternator or idler pulley.
- Push the alternator or idler pulley inward to
loosen the belt. Pull the old drive belt off the pulleys.
- Place the new and old belt side by side on the
work bench to make a comparison. The belt width and length of
the new belt must be the same. If you find a difference, check
to see that you have not gotten the wrong belt. A belt that is
too long to be adjusted properly will slip. A belt that is too
short will not fit over the pulleys. A belt with the incorrect
width or V shape could be thrown off when the engine is running.
- Install the correct belt over the pulleys.
Adjust the belt to the proper tension as described previously.
Start the engine and observe the belt in operation. Stop the
engine and recheck the tension.
- Transmission fluid
Transmission Fluid
Manual Transmissions
The manual transmission is lubricated by a
lubricant that is splashed throughout the transmission by the moving
gears. The lubricant must be at the correct level or the
transmission parts could wear out in a very short time. The interval
for lubrication level check is specified in the maintenance schedule
in the owner's manual.
- Some imported cars have a dipstick to check
manual transmission fluid level.. The engine must be off to
check the fluid with a dipstick. Remove and wipe the dipstick
with a clean rag. Then insert the dipstick back into position.
Remove it again and note the reading. Lubricant must be between
the "full" and "add" marks on the dipstick.
When you are done, replace the dipstick.
- Make manual transmission checks with the engine
off. Never put your finger into a transmission fill plug hole.
If the drive wheels are turned, your finger could be caught in
the gearing
- For most cars you will need to raise the car up
on a jack to check it (you must also be sure the car is level.).
Locate the transmission fill plug on the side of the
transmission. You may have difficulty locating it. If you do,
look for an identification diagram like the one shown below.
Do not confuse the fill plug with the drain plug, which is
located at the bottom of the transmission.
- Clean the area around the fill plug to avoid
getting dirt into the transmission. Remove the fill plug with
the correct size wrench. If the transmission is full, you may
see lubricant begin to leak out of the fill plug hole. If this
happens, replace the plug.
- You will probably find that the lubricant level
is below the level of the fill plug hole. Bend a short length of
metal wire and insert it into the fill hole. Pull the wire out
and note the lubricant on the end of the wire. The lubricant
level should be very close to the level of the fill plug.
- If the lubricant level is satisfactory, replace
the fill plug. If fluid must be added, refer to the Repair Guide
for more information on changing and adding fluid.
-
Automatic Transmission/Transaxle Fluid
Automatic transmission or automatic transaxle
fluid should be checked at regular mileage and time intervals as
specified in the owner's manual.
- Drive the car onto a level surface. Most cars
must have the engine running to make a fluid level check. Some
cars must have the transmission in NEUTRAL and others require
that it be in PARK for testing. Set the selector in the correct
mode. If the transmission is checked in NEUTRAL, block the
wheels and set the parking brake. Failure to have the
transmission in the correct gear when checking fluid level can
cause a large error in the reading.
- Raise the hood and locate the automatic
transmission/transaxle dipstick. Typically you will find the
dipstick near the transmission end of the engine at the opposite
end of the drive belts.
- Remove the dipstick and wipe it with a clean,
lint-free rag. (It's important to use a lint-free rag when
wiping the dipstick. Lint from a rag could get into parts of the
transmission and plug up passsages.) Observe the markings on the
dipstick. There is no standard marking system, so you may need
to look up an explanation of the marks in the owner's manual.
- Insert the dipstick back into its housing and
push it down until it seats. Pull it back out and observe the
fluid level in relation to the dipstick markings. While you have
the fluid on the dipstick you should observe its color and
condition. This information can help you decide if the fluid
requires changing. Clean, uncontaminated fluid has a pinkish or
reddish color. Fluid that has been overheated turns a darkish
brown or black. A white milky appearance can mean that the
engine coolant is leaking into the transmission.
- If fluid must be added or changed, refer to the
Repair Guide for more information on changing and adding fluid.
- Replace the dipstick and make sure it is seated
properly.
- Engine oil
Checking the Oil
The secret to keeping your car in good running
condition is by making sure your engine is full of clean oil. Don't
wait until you see the red oil pressure light on your dashboard. By
that time, you may have already done serious -- and expensive --
damage to your engine. You can avoid all this by making it a habit
to check your oil when you get gas. Also check your oil when you set
out on a big trip. By checking the oil frequently, you can get good
at estimating how long it takes for your engine to start running low
on oil.
In general, oil should be changed every 3,000
miles. Older cars tend to burn oil faster than newer cars, and
therefore should be checked more rigorously. Keep a record handy of
when your oil was last changed.
Here's how to check the oil yourself:
- Park on level ground and shut off the engine.
- Open the hood, locate the engine, and find the
metal loop sticking out of it at the end of a metal stalk.
That's the end of your dipstick. If you can't find it, your
owner's manual should help.
- With a rag or thick paper towel in one hand,
pull on the metal loop and remove the dipstick with the other.
Wipe the straight end of the dipstick, and push it back into the
stalk you pulled it out of.
- Wait a few seconds, and pull out the dipstick
again.
- Look at the end of the dipstick, and notice
where the oil ends. There are markings that indicate the
parameters of where the oil should reach. If the oil doesn't
reach inside the markings, you need to add at least a quart of
oil. It's also a good idea to look carefully at the oil on the
dipstick. If it is grainy or has little nuggets or dirt in it,
it's time for an oil change. The oil should look smooth.
- To add oil, make sure the engine is off. Find
the oil cap on the top of the engine and unscrew it. Pour the
oil into the hole. A funnel might help, but don't worry if you
spill a bit of it on the engine.
- Replace the oil cap and recheck the oil level
like you did before.
- Air filter
Air Filters
Even during low speed operation, the engine pulls
in a tremendous volume of air. This air has a great deal of abrasive
particles, which must be prevented from entering the engine. The air
cleaner traps the abrasive particles before they can enter the
engine. In so doing, however, it clogs itself. The air filter should
be checked every other month.
Cars with fuel injection typically have an air
filter element located in an air induction assembly like the one
shown below. The filter element is located in a rectangular box
called the air cleaner housing. The element may be removed by
unlatching a series of clamps or unscrewing a series of screws.
Cars with carburetors or throttle body fuel
injection often have a large round air cleaner assembly mounted on
top of the carburetor. The filter is located inside the air cleaner
housing. Remove the top of the air cleaner by taking off a single
wing nut as shown below.
To inspect or change the air filter element:
- First loosen and remove the latches, screws, or
wing nut. Remove the cover and then the air filter element.
- Carefully inspect the air filter element. You
will find dirt and oil on one side of the filter element. This
material has been trapped by the filter material. Any dirt and
oil buildup on the filter means it should be changed.
- Place the new filter element next to the old
one on the work bench. Carefully compare the two filter
elements. Both must have the same dimensions. The gaskets on the
top and the bottom of the filter elements must be exactly the
same.
- Place the new air filter element in the air
filter housing . Make sure the gasket surface is aligned on both
the top and bottom.
- Replace the cover and tighten the latches,
screws, or wing nut until snug. The air filter gasket must fit
correctly and seal properly. A light coat of grease on the air
cleaner gasket of an older car can improve the seal between the
air cleaner housing and the air filter element.
- Brake fluid
Brake Fluid
There are two styles of master cylinder
reservoirs. One type has a wire bail holding the reservoir cover in
place. These master cylinders are typically made from cast iron and
the reservoir and cylinder are made as one piece. Clean the top of
the cover and the surrounding area. Unsnap the bail and check the
fluid level. You will find a rubber diaphragm attached to the
underside of the cover. The diaphragm prevents dirt, water, or other
contamination from entering the fluid.
If necessary, add fluid to bring the level to
within 1/4 inch (6 mm) of the top of the reservoir. With disc
brakes, the fluid level can be expected to fall as the brake pads
wear. However, low fluid level may be caused by a leak, and a
checkup may be needed. Install the cover and snap the bail back in
place. Many late-model cars have a plastic reservoir that is mounted
on top of the master cylinder. This reservoir is transparent. It
often has a "full" and "add" line on the side.
The fluid level can be observed through the plastic without taking
off the top. Plastic reservoirs have screw-on caps that may be
removed to add fluid as shown below. You should add fluid to bring
the level to within 1/4 inch (6 mm) of the top of the reservoir.
- Washer fluid
Washer Fluid
The windshield washer system must have enough
windshield washer fluid to properly clean the windshield. Anytime
you service the windshield wipers or are under the hood, inspect and
refill any lost windshield wiper fluid.
Windshield washer fluid is available in automotive
parts stores. The fluid is often colored blue so that it is easy to
see in the washer system reservoir.
Open the hood and locate the washer reservoir.
Typically, the reservoir is transparent so the fluid can be seen
through the reservoir. Inspect the fluid level. Some reservoirs have
a "full" line, but most are filled all the way to the top.
If the level is low, remove the cap on top. Place a clean funnel in
the cap opening and pour in the washer fluid until it reaches the
correct level.
Most washer fluid containers will indicate a range
of temperatures at which it will work best. In cold weather
conditions, you will need to have windshield washer fluid that
contains antifreeze or you will need to add windshield washer
antifreeze to prevent the washer fluid from freezing.
- Battery
Battery
The battery is a common source of breakdown on the
road. A battery that fails will prevent the owner from cranking and
starting the car. You should perform a visual inspection on the
battery anytime you have the hood up.
CAUTION: Always wear eye protection when working
on a battery. Protect yourself from electrolyte splash, which can
injure skin and eyes. Never smoke or create any spark around a
battery or it might explode.
The first step in inspecting a battery is to look
for obvious damage.
You should look for:
 | Cracked or bulged case or cover
| Signs of electrolyte leakage
| Frayed insulation on battery cables
| Corrosion buildup on terminals and posts
| Loose or missing holding hardware
| Electrolyte level (if the battery has cell vent
caps) |
| | | | |
Any physical damage to the battery indicates it
must be replaced. Broken or damaged cables should also be replaced.
Corrosion can be cleaned off the post and terminals, as explained
later.
Inspect the top of the battery for dirt or
electrolyte. Too much electrolyte on the top of the battery may be
the result of overfilling. If the top of the battery is not clean,
current can flow across the foreign material. This will cause the
battery to discharge by itself when the vehicle is idle. Check the
battery hold-down to be sure it is tight. A loose hold-down could
mean the active material has vibrated off the plates.
The electrolyte level should be checked monthly on
older style non-maintenance-free batteries. During warm weather
driving, these batteries lose water out of the cells. The higher the
battery temperature and the higher the charge rate, the more gas
that is developed and the faster the water loss. Long trips in hot
weather subject the cells to high temperatures and high charging
rates. These conditions mean the electrolyte level must be checked
often. If the water drops too low, the battery will fail to
function.
Older style batteries have cell vent caps. Low
maintenance batteries have a pry-off cell cover. Remove the cell
vent caps or use a screwdriver to pry off the cell cover to inspect
the electrolyte level.
The electrolyte level should be well above the
plates. Most manufacturers have a guide ring built into the top of
the case above the cell. The electrolyte level should be filled to
the level of the guide ring. If the electrolyte level is low, add
water to the cell. Because regular tap water may have a high salt
and mineral content, you should use distilled water. The water
should be added with a plastic or rubber tool made for battery
filling, not a metal funnel. A metal object could cause a short
between the plates. Be sure not to overfill the cell. This would
dilute the electrolyte strength and cause an acid buildup on the
outside of the battery.
Power steering fluid
Power Steering Fluid
Most cars today are equipped with a power steering
system. Many power steering systems use hydraulic power. These
systems use a power steering pump driven by a belt from the
crankshaft as shown below. The pump moves fluid under pressure
through hoses to the steering gear. The pressure is used in the
steering gear to reduce steering effort. A reservoir for fluid is
attached to the rear of the pump. Checking the fluid level in this
reservoir is a common under hood maintenance job.
The fluid in the power steering system provides
lubrication as well as the power assist. Low fluid level can cause a
lack of power assist, excessive noise, and rapid part wear. The
power steering fluid level should be checked at regular intervals.
CAUTION: Check the fluid level with the engine off
to prevent possible injury from moving parts.
The fluid is checked at the pump reservoir with a
dipstick attached to the reservoir cap. Before removing the
reservoir cap, wipe the outside of the cap and reservoir to prevent
dirt from falling into the reservoir. Pull the dipstick out and note
the fluid reading. The fluid should be between the "hot"
and "cold" mark on the dipstick. There are hot and cold
marks because the fluid expands as it gets hot. If the level is
below the "add" mark, you will have to add fluid to bring
it up to the correct level. You should use only the type of fluid
listed in the owner's or shop service manual. Older cars use
automatic transmission fluid. Special power steering fluids are used
on late-model cars. Add the correct amount of fluid and replace the
dipstick.
Engine Noise
Diagnosis
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