1991 FORD FESTIVA tire type

2. Remove main bearing cap bolts. Remove cap and lower bearing insert. Use bearing remover or fabricated cotter key to remove upper
bearing insert. Insert bearing remover in journal lubrication hole. Rotate crankshaft in normal direction of operation only. Repeat
procedure for remaining main bearings.
3. Check bearings for abnormal wear. Check crankshaft for grooves, scratches and pitting. Using Plastigage method, check clearance of
main bearing-to-crankshaft. Always keep at least 2 bearings and caps tight during clearance check. See, at end of article,
CRANKSHAFT MAIN & CONNECTING ROD BEARINGS
table under ENGINE SPECIFICATIONS.
4. Lubricate and install new bearings in cap and block. Match bearing tangs with notch in cap and block. Position cap in its proper
location and position. Install cap bolts and tighten to specification. See TORQUE SPECIFICATIONS
table at end of article. Repeat
procedure for remaining main bearings.
CRANKSHAFT END PLAY
Check crankshaft end play with dial indicator. End play should be .0031-.0111" (.08-.282 mm). Service limit is .012" (.30 mm). If end play is
not within specification, replace thrust bearings as necessary.
CYLINDER BLOCK
1. Using straightedge and feeler gauge, check entire cylinder head surface of cylinder block. Ensure warpage does not exceed .006" (.15
mm). If warpage exceeds specification, cylinder block surface can be machined a maximum of .008" (.20 mm).
2. Replace cylinder block if it needs to be machined more than .008" (.20 mm). Check cylinder bore for wear, out-of-round, taper and
piston fit. See CYLINDER BORE SPECIFICATIONS
table. Oversize pistons are available in .010" and .020" (.25 mm and .50 mm).
CYLINDER BORE SPECIFICATIONS
LUBRICATION
ENGINE OILING SYSTEM
Oiling system is force-feed type and uses a full-flow oil filter. Oil is retrieved from oil pan by oil pump pick-up tube and distributed to oil
filter. Oil is then filtered and routed throughout engine.
Crankcase Capacity
1.3 L crankcase capacity is 3.2 qts. (3.0 L) without filter change and 3.6 qts. (3.4 L) with filter change. For 1.6 L vehicles, capacity is 3.2 qts
(3.2 L) without filter and 3.72 qts. (3.5 L) with filter.
Normal Oil Pressure (Hot)
Normal oil pressure is 50-64 psi (3.5-4.5 kg/cm2 ) at 3000 RPM.
Pressure Regulator Valve
Pressure regulator valve is located in oil pump body and is nonadjustable.
OIL PUMP
Removal
Remove oil pan, pick-up tube and screen, timing belt and crankshaft sprocket. Remove front engine cover bolts and remove front cover.
R e mo ve b o l t s r e t a in in g p u mp c o ve r t o b a c k sid e o f fr o n t c o ve r h o u sin g.
2) Remove pump cover and inner and outer gears. Pry out front seal from front cover. Remove cotter pin. Remove pressure regulator retainer,
spring and valve.
OIL PUMP SPECIFICATIONS or replacem ent.
ApplicationIn. (mm)
Cylinder Diameter
Standard Bore
1.3L2.7953-2.7960 (71.000-71.019)
1.6L3.0709-3.0716 (78.000-78.019)
Maximu m Bo re
1.3L2.8020 (71.17)
1.6L3.0905-3.0913 (78.500-78.519)
Maximu m Ou t -Of-Ro u n d & Tap er.0007 (.019)
Piston-To-Bore Clearance.006 (.15)
ApplicationIn. (mm)
Inner Gear-To-Outer Gear
1.3L.008 (.20)
1.6L.0008-.0063 (.02-.16)
Outer Gear-To-Housing
1.3L.009 (.22)
1.6L.0035-.0071 (.09-.18)
End Play
1.3L.006 (.14)
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A "howling" or "whining" noise from the ring and pinion gear can be caused by an improper gear pattern, gear damage, or improper bearing
preload. It can occur at various speeds and driving conditions, or it can be continuous.
Before disassembling axle to diagnose and correct gear ke sure that tires, exhaust, and vehicle trim have been checked as possible causes.
Chuckle
This is a particular rattling noise that sounds like a stick against the spokes of a spinning bicycle wheel. It occurs while decelerating from 40
MPH and usually can be heard until vehicle comes to a complete stop. The frequency varies with the speed of the vehicle.
A chuckle that occurs on the driving phase is usually caused ive clearance due to differential gear wear, or by a damaged tooth on the coast
side of the pinion or ring gear. Even a very small tooth nick or a ridge on the edge of a gear tooth is enough the cause the noise.
This condition can be corrected simply by cleaning the gear tooth nick or ridge with a small grinding wheel. If either gear is damaged or scored
badly, the gear set must be replaced. If metal has broken loose, the carrier and housing must be cleaned to remove particles that could cause
damage.
Knock
This is very similar to a chuckle, though it may be louder, and occur on acceleration or deceleration. Knock can be caused by a gear tooth that
is damaged on the drive side of the ring and pinion gears. Ring gear bolts that are hitting the carrier casting can cause knock. Knock can also be
due to excessive end play in the axle shafts.
Clunk
Clunk is a metallic noise heard when an automatic transmission is engaged in Reverse or Drive, or when throttle is applied or released. It is
caused by backlash somewhere in the driveline, but not necessarily in the axle. To determine whether driveline clunk is caused by the axle,
check the total axle backlash as follows:
1. Raise vehicle on a frame or twinpost hoist so that drive wheels are free. Clamp a bar between axle companion flange and a part of the
frame or body so that flange cannot move.
2. On conventional drive axles, lock the left wheel to keep it from turning. On all models, turn the right wheel slowly until it is felt to be in
Drive condition. Hold a chalk marker on side of tire about 12" from center of wheel. Turn wheel in the opposite direction until it is
again felt to be in Drive condition.
3. Measure the length of the chalk mark, which is the total axle backlash. If backlash is one inch or less, drive axle is not the source of
clunk noise.
Bearing Whine
Bearing whine is a high-pitched sound similar to a whistle. It is usually caused by malfunctioning pinion bearings. Pinion bearings operate at
drive shaft speed. Roller wheel bearings may whine in a similar manner if they run completely dry of lubricant. Bearing noise will occur at all
driving speeds. This distinguishes it from gear whine, which usually comes and goes as speed changes.
Bearing Rumble
Bearing rumble sounds like marbles being tumbled. It is usually caused by a malfunctioning wheel bearing. The lower pitch is because the
wheel bearing turns at only about 1/3 of drive shaft speed.
Chatter On Turns
This is a condition where the entire front or rear of vehicle vibrates when vehicle is moving. The vibration is plainly felt as well as heard. Extra
differential thrust washers installed during axle repair can cause a condition of partial lock-up that creates this chatter.
Axle Shaft Noise
Axle shaft noise is similar to gear noise and pinion bearing whine. Axle shaft bearing noise will normally distinguish itself from gear noise by
occurring in all driving modes (Drive, cruise, coast and float), and will persist with transmission in Neutral while vehicle is moving at problem
speed.
If vehicle displays this noise condition, remove suspect parts, replace wheel seals and install a new set of bearings. Re-evaluate vehicle for
noise before removing any internal components.
Vibration
Vibration is a high-frequency trembling, shaking or grinding condition (felt or heard) that may be constant or variable in level and can occur
during the total operating speed range of the vehicle.
The types of vibrations that can be felt in the vehicle can d into 3 main groups:
Vibrations of various unbalanced rotating parts of the vehicle.
Resonance vibrations of the body and frame structures caused by rotating of unbalanced parts.
Tip-in moans of resonance vibrations from stressed engine or exhaust system mounts or driveline flexing modes.
DRIVE AXLE - RWD TROUBLE SHOOTING
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing. For definitions of listed
noises or sounds, see DRIVE AXLE
- NOISE DIAGNOSIS under POWERTRAIN.
Page 28 of 36 MITCHELL 1 ARTICLE - GENERAL INFORMATION Trouble Shooting - Basic Procedures
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CLUNK
Clunk is a metallic noise heard when an automatic transmission is engaged in Reverse or Drive, or when throttle is applied or released. It is
caused by backlash somewhere in the driveline, but not necessarily in the axle. To determine whether driveline clunk is caused by the axle,
check the total axle backlash as follows:
1. Raise vehicle on a frame or twinpost hoist so that drive wheels are free. Clamp a bar between axle companion flange and a part of the
frame or body so that flange cannot move.
2. On conventional drive axles, lock the left wheel to keep it from turning. On all models, turn the right wheel slowly until it is felt to be in
drive condition. Hold a chalk marker on side of tire about 12" from center of wheel. Turn wheel in the opposite direction until it is again
felt to be in drive condition.
3. Measure the length of the chalk mark, which is the total axle backlash. If backlash is one inch or less, clunk will not be eliminated by
overhauling drive axle.
BEARING WHINE
Bearing whine is a high-pitched sound similar to a whistle. It is usually caused by malfunctioning pinion bearings. Pinion bearings operate at
driveshaft speed. Roller wheel bearings may whine in a similar manner if they run completely dry of lubricant. Bearing noise will occur at all
driving speeds. This distinguishes it from gear whine, which usually comes and goes as speed changes.
BEARING RUMBLE
Bearing rumble sounds like marbles being tumbled. It is usually caused by a malfunctioning wheel bearing. The lower pitch is because the
wheel bearing turns at only about 1/3 of driveshaft speed.
CHATTER ON TURNS
This is a condition where the whole front or rear vibrates when vehicle is moving. The vibration is easily felt and heard. Extra differential
thrust washers installed during axle repair can cause a condition of partial lock-up that creates the chatter.
AXLE SHAFT NOISE
Axle shaft noise is similar to gear noise and pinion bearing whine. Axle shaft bearing noise will normally distinguish itself from gear noise by
occurring in all driving modes. Noise will persist with transmission in neutral while vehicle is moving at problem speed.
If vehicle displays this noise condition, remove suspect axle shafts and replace axle bearings. Re-evaluate vehicle for noise before removing
any internal components.
VIB R AT ION
Vibration is a high-frequency trembling, shaking or grinding condition (felt or heard) that may be constant or variable in level and con occur
during the total operating speed range of the vehicle.
The types of vibrations that can be felt in the vehicle can be divided into 3 main groups:
Vibrations of various unbalanced rotating parts of the vehicle.
Resonance vibrations of the body and frame structures caused by rotating of unbalance parts.
Tip-in moans of resonance vibrations from stressed engine or exhaust system mounts or driveline flexing modes. NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00002193
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Circuits with external injector resistors. Used predominately on some Asian & European systems, they are used to reduce the available
voltage to an injector in order to limit the current flow. This lower voltage can cause a dim flash on a noid light designed for full voltage.
Circuits with current controlled injector drivers (e.g. "Peak and Hold"). Basically, this type of driver allows a quick burst of
voltage/current to flow and then throttles it back significantly for the remainder of the pulse width duration. If a noid light was designed
for the other type of driver (voltage controlled, e.g. "Saturated"), it will appear dim because it is expecting full voltage/current to flow
for the entire duration of the pulse width.
Let's move to the other situation where a noid light flashes normally when it should be dim. This could occur if a more sensitive n o id l igh t is
used on a higher voltage/amperage circuit that was weakened enough to cause problems (but not outright broken). A circuit with an actual
problem would thus appear normal.
Let's look at why. A noid light does not come close to consuming as much amperage as an injector solenoid. If there is a partial driver failure
or a minor voltage drop in the injector circuit, there can be adequate amperage to fully operate the noid light BUT NOT ENOUGH TO
OPERATE THE INJECTOR.
If this is not clear, picture a battery with a lot of corrosion on the terminals. Say there is enough corrosion that the starter motor will not
operate; it only clicks. Now imagine turning on the headlights (with the ignition in the RUN position). You find they light normally and are
fully bright. This is the same idea as noid light: There is a problem, but enough amp flow exists to operate the headlights ("noid light"), but not
the starter motor ("injector").
How do you identify and avoid all these situations? By using the correct type of noid light. This requires that you understanding the types of
injector circuits that your noid lights are designed for. There are three. They are:
Systems with a voltage controlled injector driver. Another way to say it: The noid light is designed for a circuit with a "high" resistance
injector (generally 12 ohms or above).
Systems with a current controlled injector driver. Another way to say it: The noid light is designed for a circuit with a low resistance
injector (generally less than 12 ohms) without an external injector resistor.
Systems with a voltage controlled injector driver and an external injector resistor. Another way of saying it: The noid light is designed
for a circuit with a low resistance injector (generally less than 12 ohms) and an external injector resistor.
If you are not sure which type of circuit your noid light is designed for, plug it into a known good car and check out the results. If it flashes
normally during cranking, determine the circuit type by finding out injector resistance and if an external injector resistor is used. You now
know enough to identify the type of injector circuit. Label the noid light appropriately.
Next time you need to use a noid light for diagnosis, determine what type of injector circuit you are dealing with and select the appropriate
noid light.
Of course, if you suspect a no-pulse condition you could plug in any one whose connector fit without fear of misdiagnosis. This is because it is
unimportant if the flashing light is dim or bright. It is only important that it flashes.
In any cases of doubt regarding the use of a noid light, a lab scope will overcome all inherent weaknesses.
OVERVIEW OF DVOM
A DVOM is typically used to check injector resistance and available voltage at the injector. Some techs also use it check injector on-time
either with a built-in feature or by using the dwell/duty function.
There are situations where the DVOM performs these checks dependably, and other situations where it can deceive you. It is important to be
aware of these strengths and weaknesses. We will cover the topics above in the following text.
Checking Injector Resistance
If a short in an injector coil winding is constant, an ohmmeter will accurately identify the lower resistance. The same is true with an open
winding. Unfortunately, an intermittent short is an exception. A faulty injector with an intermittent short will show "good" if the ohmmeter
cannot force the short to occur during testing.
Alcohol in fuel typically causes an intermittent short, happening only when the injector coil is hot and loaded by a current high e n o u gh t o
jump the air gap between two bare windings or to break down any oxides that may have formed between them.
When you measure resistance with an ohmmeter, you are only applying a small current of a few milliamps. This is nowhere near enough to
load the coil sufficiently to detect most problems. As a result, most resistance checks identify intermittently shorted injectors as being normal.
There are two methods to get around this limitation. The first is to purchase an tool that checks injector coil windings under full load. The
Kent-Moore J-39021 is such a tool, though there are others. The Kent-Moore costs around $240 at the time of this writing and works on many
different manufacturer's systems.
The second method is to use a lab scope. Remember, a lab scope allows you to see the regular operation of a circuit in real time. If an injector
is having an short or intermittent short, the lab scope will show it.
Checking Available Voltage At the Injector
Verifying a fuel injector has the proper voltage to operate correctly is good diagnostic technique. Finding an open circuit on the feed circuit
like a broken wire or connector is an accurate check with a DVOM. Unfortunately, finding an intermittent or excessive resistance problem with
a DVOM is unreliable.
Let's explore this drawback. Remember that a voltage drop due to excessive resistance will only occur when a circuit is operating? Since the
injector circuit is only operating for a few milliseconds at a time, a DVOM will only see a potential fault for a few milliseconds. The remaining
90+% of the time the unloaded injector circuit will show normal battery voltage. NOTE:Som e noid lights can m eet both the second and third categories sim ultaneously.
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Since DVOMs update their display roughly two to five times a second, all measurements in between are averaged. Because a potential voltage
drop is visible for such a small amount of time, it ge t s "a ve r a ge d o u t ", c a u sin g yo u t o miss it .
Only a DVOM that has a "min-max" function that checks EVERY MILLISECOND will catch this fault consistently (if used in that mode). The
Fluke 87 among others has this capability.
A "min-max" DVOM with a lower frequency of checking (100 millisecond) can miss the fault because it will probably check when the injector
is not on. This is especially true with current controlled driver circuits. The Fluke 88, among others fall into this category.
Outside of using a Fluke 87 (or equivalent) in the 1 mS "min-max" mode, the only way to catch a voltage drop fault is with a lab scope. You
will be able to see a voltage drop as it happens.
One final note. It is important to be aware that an injector circuit with a solenoid resistor will always show a voltage drop when the circuit is
energized. This is somewhat obvious and normal; it is a designed-in voltage drop. What can be unexpected is what we already covered--a
voltage drop disappears when the circuit is unloaded. The unloaded injector circuit will show normal battery voltage at the injector.
Remember this and do not get confused.
Checking Injector On-Time With Built-In Function
Several DVOMs have a feature that allows them to measure injector on-time (mS pulse width). While they are accurate and fast to hookup,
they have three limitations you should be aware of:
They only work on voltage controlled injector drivers (e.g "Saturated Switch"), NOT on current controlled injector drivers (e.g. "Peak &
Hold").
A few unusual conditions can cause inaccurate readings.
Varying engine speeds can result in inaccurate readings.
Regarding the first limitation, DVOMs need a well-defined injector pulse in order to determine when the injector turns ON and OFF. Voltage
controlled drivers provide this because of their simple switch-like operation. They completely close the circuit for the entire duration of the
pulse. This is easy for the DVOM to interpret.
The other type of driver, the current controlled type, start off well by completely closing the circuit (until the injector pintle opens), but then
they throttle back the voltage/current for the duration of the pulse. The DVOM understands the beginning of the pulse but it cannot figure out
the throttling action. In other words, it cannot distinguish the throttling from an open circuit (de-energized) condition.
Yet current controlled injectors will still yield a millisecond on-time reading on these DVOMs. You will find it is also always the same,
regardless of the operating conditions. This is because it is only measuring the initial completely-closed circuit on-time, which always takes the
same amount of time (to lift the injector pintle off its seat). So even though you get a reading, it is useless.
The second limitation is that a few erratic conditions can cause inaccurate readings. This is because of a DVOM's slow display rate; roughly
two to five times a second. As we covered earlier, measurements in between display updates get averaged. So conditions like skipped injector
pulses or intermittent long/short injector pulses tend to get "averaged out", which will cause you to miss important details.
The last limitation is that varying engine speeds can result in inaccurate readings. This is caused by the quickly shifting injector on-time as the
engine load varies, or the RPM moves from a state of acceleration to stabilization, or similar situations. It too is caused by the averaging of all
measurements in between DVOM display periods. You can avoid this by checking on-time when there are no RPM or load changes.
A lab scope allows you to overcome each one of these limitations.
Checking Injector On-Time With Dwell Or Duty
If no tool is available to directly measure injector millisecond on-time measurement, some techs use a simple DVOM dwell or duty cycle
functions as a replacement.
While this is an approach of last resort, it does provide benefits. We will discuss the strengths and weaknesses in a moment, but first we will
look at how a duty cycle meter and dwell meter work.
How A Duty Cycle Meter and Dwell Meter Work
All readings are obtained by comparing how long something has been OFF to how long it has been ON in a fixed time period. A dwell meter
and duty cycle meter actually come up with the same answers using different scales. You can convert freely between them. See
RELATIONSHIP BETWEEN DWELL & DUTY CYCLE READINGS TABLE
.
The DVOM display updates roughly one time a second, although some DVOMs can be a little faster or slower. All measurements during this
update period are tallied inside the DVOM as ON time or OFF time, and then the total ratio is displayed as either a percentage (duty cycle) or
degrees (dwell meter).
For example, let's say a DVOM had an update rate of exactly 1 second (1000 milliseconds). Let's also say that it has been measuring/tallying
an injector circuit that had been ON a total of 250 mS out of the 1000 mS. That is a ratio of one-quarter, which would be displayed as 25%
duty cycle or 15° dwell (six-cylinder scale). Note that most duty cycle meters can reverse the readings by selecting the positive o r n e ga t ive
slope to trigger on. If this reading were reversed, a duty cycle meter would display 75%.
Strengths of Dwell/Duty Meter
The obvious strength of a dwell/duty meter is that you can compare injector on-time against a known-good reading. This is the only practical
way to use a dwell/duty meter, but requires you to have known-good values to compare against.
Another strength is that you can roughly convert injector mS on-time into dwell reading with some computations.
A final strength is that because the meter averages everything together it does not miss anything (though this is also a severe weakness that we
will look at later). If an injector has a fault where it occasionally skips a pulse, the meter registers it and the reading changes accordingly.
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This, coupled with the inherent resistance of the driver's transistor, impedes the current flow even more. So, what is a known good value for a
dynamic current draw on a voltage controlled bank of injectors? The waveform pattern shown below indicates a good parallel injector current
flow of 2 amps. See Fig. 4
.
Note that if just one injector has a resistance problem and partially shorts, the entire parallel bank that it belongs to will draw more current.
This can damage the injector driver.
The waveform pattern in Fig. Fig. 5
indicates this type of problem with too much current flow. This is on other bank of injectors of the same
vehicle; the even side. Notice the Lab Scope is set on a one amp per division scale. As you can see, the current is at an unacceptable 2.5 amps.
It is easy to find out which individual injector is at fault. All you need to do is inductively clamp onto each individual injector and compare
them. To obtain a known-good value to compare against, we used the good bank to capture the waveform in Fig. Fig. 6
. Notice that it limits
current flow to 750 milliamps.
The waveform shown in Fig. Fig. 7
illustrates the problem injector we found. This waveform indicates an unacceptable current draw of just
over one amp as compared to the 750 milliamp draw of the known-good injector. A subsequent check with a DVOM found 8.2 ohms, which is
under the 12 ohm specification.

Fig. 4: Injector Bank w/Normal Current Flow
- Current Pattern

Fig. 5: Injector Bank w/Excessive Current Flow
- Current Pattern

Fig. 6: Single Injector w/Normal Current Flow
- Current Pattern
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Back To Article
1991 GENERAL SERVICING
A/C Com pressor Refrigerant Oil Checking
ISOLATING COMPRESSOR
1. Connect service gauge set to the compressor service valves and open compressor valves slightly (turn in clockwise). Start engine and
operate air conditioning. Slowly turn compressor suction valve clockwise toward closed (front-seated) position.
2. When suction pressure is reduced to zero or less, turn off engine and compressor and quickly turn suction valve stem in to full front-
seated position. Suction pressure should be slightly above zero. Turn discharge valve into front-seated position.
3. To check oil level, slowly open compressor crankcase plug to relieve any remaining pressure. After oil level is corrected, cap service
gauge ports on both valves. Back-seat suction service valve to allow refrigerant to enter compressor. Open discharge valve halfway.
4. Loosen discharge service valve cap, allowing refrigerant pressure to force air out of compressor. Back-seat service valve and tighten cap.
Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used in the air conditioning system. This oil is highly refined and dehydrated to a point
where moisture content is less than 10 parts per million. The oil container must be tightly closed at all times when not in use, or moisture will
be absorbed into the refrigerant oil from the air.
SERVICING PRECAUTIONS
DISCHARGING SYSTEM PRECAUTIONS
If compressor has stem-type service valves, it can be isolated and removed without discharging entire system. See ISOLATING
COMPRESSOR at the beginning of this article. Otherwise, discharge system completely before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all fittings to be opened. Always use 2 wrenches when tightening or loosening fittings
to avoid twisting or distorting lines. Cap or plug all openings as soon as lines are removed. DO NOT remove caps until immediately before
connections are made. This will keep entry of air and moisture to a minimum.
CONNECTING LINES AND FITTINGS
A new gasket or "O" ring should be used in all instances when connecting lines or fittings. Dip "O" ring in new refrigerant oil and ensure it is
not twisted during installation. Always use 2 wrenches to prevent damage to lines and fittings.
PLACING SYSTEM IN OPERATION
After component service or replacement has been completed and all connections have been made, evacuate system thoroughly with a vacuum
pump. Charge system with proper amount of refrigerant and perform a leak test. See REFRIGERANT OIL & R-12 SPECIFICATIONS chart in
this section for system capacities. Be sure to check all fittings that have been opened. After system has been leak tested, make a system
performance check.
ATSUGI ROTARY VANE DRAIN & REFILL
1. Before checking and adjusting oil level, operate compressor at engine idling speed, with controls set for maximum cooling and high
blower speed, for 20 to 30 minutes to return oil to compressor.
2. Stop engine, discharge refrigerant and remove compressor from vehicle. See SERVICING PRECAUTIONS at beginning of article. Drain
compressor oil from compressor discharge port and measure the amount. Oil is sometimes hard to drain when compressor is cool.
Remove oil while compressor is warm.
3. If the amount drained is less than 3 ounces, conduct leak tests at system connections, and if necessary, repair or replace faulty parts.
Check purity of oil and adjust oil level as follows.
4. If amount drained was above 3 ounces, oil level is right. Pour in same amount as was drained. If amount drained was below 3 ounces,
pour in 3 ounces of new refrigerant oil.
BOSCH 6-CYL DRAIN & REFILL
1. Before checking and adjusting oil level, operate compressor at engine idling speed, with controls set for maximum cooling and high
blower speed, for 20 to 30 minutes to return oil to compressor.
2. Stop engine and discharge refrigerant. Remove refrigerant oil level inspection plug on side of compressor. Oil should be at lower lip of
threaded hole. Add necessary new refrigerant oil (if low). Replace inspection plug and tighten to 10-12 ft. lbs. (14-16 N.m). NOTE:Only com pressors with stem -type service valves can be isolated.
NOTE:Recent findings by the EPA indicate that refrigerant is harm ful to the earth's protective Ozone layer.
When discharging refrigerant, DO NOT allow refrigerant to enter the atm osphere. If available, use
refrigerant recovery/recycle system s when discharging system . Always follow m anufacturer's
instructions.
NOTE:Air conditioning system s will not norm ally need addition of refrigerant oil unless definite oil loss has
occurred due to ruptured lines, leaking com pressor seals, com pressor overhaul or com ponent
replacem ent.
Page 1 of 4 MITCHELL 1 ARTICLE - 1991 GENERAL SERVICING A/C Compressor Refrigerant Oil Checking
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A/C COMPRESSOR SERVICING
1991 GENERAL SERVICING Com pressor Service
ISOLATING COMPRESSOR
1. Connect service gauge set to the compressor service valves and open compressor valves slightly (turn in clockwise). Start engine and
operate air conditioning. Slowly turn compressor suction valve clockwise toward closed (front-seated) position.
2. When suction pressure is reduced to zero or less, turn off engine and compressor and quickly turn suction valve stem in to full front-
seated position. Suction pressure should be slightly above zero. Turn discharge valve into front-seated position.
3. To check oil level, slowly open compressor crankcase plug to relieve any remaining pressure. After oil level is corrected, cap service
gauge ports on both valves. Back-seat suction service valve to allow refrigerant to enter compressor. Open discharge valve halfway.
4. Loosen discharge service valve cap, allowing refrigerant pressure to force air out of compressor. Back-seat service valve and tighten cap.
Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used in the air conditioning system. This oil is highly refined and dehydrated to a point
where moisture content is less than 10 parts per million. The oil container must be tightly closed at all times when not in use, or moisture will
be absorbed into the refrigerant oil from the air.
DISCHARGING SYSTEM PRECAUTIONS
If compressor has stem-type service valves, it can be isolated and removed without discharging entire system. Otherwise, discharge system
completely using approved refrigerant recovery/recycling equipment before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all fittings to be opened. Always use 2 wrenches when tightening or loosening fittings
to avoid twisting or distorting lines. Cap or plug all openings as soon as lines are removed. Do not remove caps until immediately before
connections are made. This will keep entry of air and moisture to a minimum.
CONNECTING LINES AND FITTINGS
A new gasket or "O" ring should be used in all instances when connecting lines or fittings. Dip "O" ring in new refrigerant oil and ensure it is
not twisted during installation. Always use 2 wrenches to prevent damage to lines and fittings.
PLACING SYSTEM IN OPERATION
After component service or replacement has been completed and all connections have been made, evacuate system thoroughly with a vacuum
pump. Charge system with proper amount of refrigerant and perform a leak test. See REFRIGERANT OIL & R-12 SPECIFICATIONS chart in
this section for system capacities. Be sure to check all fittings that have been opened. After system has been leak tested, make a system
performance check.
ATSUGI ROTARY VANE CLUTCH R & I
Removal
When replacing compressor clutch, be careful not to scratch shaft or bend pulley. When removing center bolt, hold clutch disc with Clutch
Holder (KV99231010). Using Hub Puller (KV998VR001 & KV99231010), remove clutch disc. When removing pulley, remove lock nut with
Hub Socket (KV99235160).
Installation
Wipe oil off clutch surface. Adjust disc pulley clearance to .012-.024" (.3-.6 mm). Tighten center bolt to 80-104 INCH lbs. (9.1-11.8 N.m).
Tighten clutch lock nut to 22-29 ft. lbs. (29-39 N.m). See Fig. 1
. CAUT ION: When discharging air conditioning system , use only approved refrigerant recovery/recycling
equipm ent. Make every attem pt to avoid discharging refrigerant into the atm osphere.
NOTE:Only com pressors with stem -type service valves can be isolated.
CAUT ION: When discharging air conditioning system , use only approved refrigerant recovery/recycling
equipm ent. Make every attem pt to avoid discharging refrigerant into the atm osphere.
NOTE:Air conditioning system s will not norm ally need addition of refrigerant oil unless definite oil loss has
occurred due to ruptured lines, leaking com pressor seals, com pressor overhaul or com ponent
replacem ent.
Page 1 of 18 MITCHELL 1 ARTICLE - A/C COMPRESSOR SERVICING 1991 GENERAL SERVICING Compressor Service
3/10/2009 http://www.eautorepair.net/app/PrintItems.asp?S0=2097152&S1=0&SG=%7B9B990D68%2D660A%2D45E9%2D8F46%2DE
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