Monthly Up-Dates
A/C MOTORS LLC
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MOBILE AIR CONDITIONING DIVISION
WE RECYCLE
UP-DATES
Honda:
Inoperative air conditioning.
1998
Passport built through VIN 4S6C.58W.W4423374 complaining that the air
conditioning system in the truck is blowing warm air. If he does, head
immediately to the underhood fuse box and check the 10-amp No. 5 fuse. If it's
blown, chances are real good that the lead wire for the compressor clutch coil
has shorted out on the power steering pump or compressor pulley, reports Honda.
Replacing the clutch coil, pulley, drive plate and related hardware from a
special repair kit (Part No. 8-97183-481-0) should get the a/c system up and
running again. After the new parts are installed, use a mini wire tie to secure
the clutch coil lead wire away from all rotating components to prevent an encore
performance.
Dodge Truck: Insufficient a/c output
Drivers
of 2004-05 4.7L Durango SUVs built on or before 5/9/05 may come into your shop
complaining of insufficient air conditioning output during extended idling or
while driving in traffic in hot ambient temperatures. According to Dodge,
installing a new-calibration front expansion valve (Part No. 05061342AD) and/or
a new condenser fan and shroud assembly (Part No. 52029175AD) should restore the
a/c performance to your customers' liking.
To help you figure out which parts require replacement, check when the truck was
built. If it's before 12/7/04, install the new expansion valve and O-rings (Part
No. 4882136, 1/2-in. diameter; 4882137, 3/4-in. diameter), along with the new
fan/shroud assembly. If the build date is between 12/7/04 and 5/9/05, replace
only the fan/shroud assembly because the new expansion valve is already
installed.
Lexus: A/C problems
Owners of 2007 RX 350 sport/utes may come into your shop one day with a complaint that the a/c light blinks continuously and/or that a Check A/C System message is displayed on the driver information panel. Lexus attributes both problems to internal defects in the a/c amplifier. Installing a new-design, modified amplifier (Part No. 88650-0E021) should eliminate further trouble. For your information, the revised part found its way into production at the following VIN breakpoints
| Model | Plant | VIN |
| 2WD | TMK | JTJGK31U#70004858 |
| 4WD | TMK | JTJGK31U#72013500 |
| 2WD | TMMC | 2T2GK31U#7C011001 |
| 4WD | TMMC | 2T2GK31U#7C018238 |
GM Truck: Hissing or gurgling noise from interior
Drivers of 2003-06 GM full-size
pickups and SUVs (complete list below) may complain of a hissing or gurgling
sound that seems to emanate from the instrument panel. With a little prodding
they'll probably tell you that the noise is most noticeable at idle with the a/c
compressor engaged, and can continue for five to ten seconds after the
compressor disengages or the air conditioning system is turned off.
According to GM, the most likely cause of the noise is the expansion of the
refrigerant as it passes through the orifice tube. Installing a new-design
liquid line into the a/c system should eradicate the annoyance immediately.
Vehicles that are susceptible to the condition are Cadillac Escalades; Chevy
Avalanches, Silverados, Suburbans and Tahoes; and GMC Sierras and Yukons. Here
are the parts particulars for the new liquid line:
Ford: No air conditioning
Owners of 2005-06 4.6L Mustangs may
come into your shop complaining that the a/c system blows warm air. If the
system has a full refrigerant charge, no fuses are blown and the compressor
clutch won't engage, chances are good that the clutch has gone belly-up, says
Ford. Installing a new clutch assembly and revised orifice tube, then recharging
the system to a new refrigerant spec of 26 oz., should bring the cooling
performance back into check. After you're done with the parts swap, you'll need
to fill out a climate control information decal and affix it underhood to alert
the next tech that works on the car of the installation.
The recommended repair for this symptom is to reposition the blower motor.
A. Remove the right side sound insulator.
B. Loosen the three blower motor retainer bolts. (Do not remove bolts) #1
C. Shift motor as far as allowed toward the vent tube. #2
D. Re-tighten the retainer bolts.
E. Re-install right side sound insulator
Applies
To: All A/C-equipped Honda models that use a heater valve cable.
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Condition: Customer complains that the
A/C stops cooling and blows warm air when the vehicle is idling for an
extended period of time, such as sitting in traffic. |
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H 6 Series
Compressor Body Leaks The Harrison 6 cylinder compressors, in particular the DA6, HR6, HD6 and the HT6 have been known for their body leaks. Each of these of compressors consists of four separate housings. Upon assembly these four housings are held together with six through bolts that pass from the front nose plate and thread into the rear head plate. Most compressors with horizontal pumping pistons are aligned through the use of a dowel pin that aligns the housings while these are not. It is important to remember this point as you read on. These compressors may be mounted on the vehicle in one of two fashions; the compressor could fit into a single mounting bracket that holds the compressor at four points. There also could be two separate brackets, one for the front of the compressor and one for the rear of the compressor. Why are these compressor mounts causing so much trouble? • Single solid bracket
-Typically used with the HT6 - There have been some stories of
these brackets warping. Most of these brackets are of cast aluminum
so warping would be difficult. However, if the bolts are improperly
torqued, as the bracket material is heated and cooled in the
engine compartment, the bracket and the compressor would conform
(twist or warp) to each other. If the bolsters or pads of the
cradle that the compressor sits on are not 100% square and if
the compressor does not lay flat on all four pads, a twisting
or rocking action could present a problem even if the compressor
is properly torqued. If the compressor does not sit solidly
on all four positions, and the compressor is torqued down into
the mounting cradle, the non-doweled compressor body will twist
and invariably leak or make noise.
To assure a solid fit, place the compressor in the cradle and try to rock it. If the compressor rocks back and forth, place a shim or standard washer between the compressor and the bracket. Torque the four bolts evenly and alternately but make sure the compressor does not rock in the cradle before the bolts are torqued.
• Dual bracket - used
with DA6, HD6 and HR6 - Most installers will start the four compressor
mounting bolts and then use an air ratchet to tighten them down.
If there is any alignment variation between the two brackets,
the tightening process will twist the case and create a body
leak or noise. To assure that the brackets conform to the compressor
and not the compressor to the brackets, loosen the brackets from
the engine block. Snug down the compressor mounting bolts.
Tighten the bracket to engine bolts then torque the compressor
mounting bolts. Any amount of case twisting could be considered one of the causes for premature piston wear, noisy operation, and eventual compressor failure. Always keep in mind that over
tightening, under tightening or any compressor mounting misalignment
will cause premature wear and noise. This is especially true
since most compressors are now made of aluminum and are very
susceptible to this twisting problem.
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Mercedes-Benz Tech Tip: A/C Compressor Clutch Won't Engage
Problem:
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Updates
June 2006
Diagnostic Information To
Consider Before Replacing an A/C Compressor
A recently completed analysis of air conditioning compressors
in General Motors vehicles that had been replaced for noise, vibration and
insufficient cooling concerns has indicated a high number of “no trouble found”
results. Further studies have shown that the root cause of the customer concerns
that might lead to a compressor replacement was often a state of refrigerant
charge issue or in another area or system of the vehicle.
The A/C system refrigerant charge level, either high or low, has been found to
be a major contributor to unnecessary compressor replacement. The ability of a
refrigerant recycling/recharging tool to recover and measure the weight of the
A/C system refrigerant charge will help the technician make a more accurate
diagnosis of a charge level concern prior to any component replacement.
A thorough visual inspection should always be performed before
any tests or repairs are done. Doing so may find an obvious problem that will
save time and eliminate the need for extensive diagnosis. Some additional items,
as listed below, should be considered before a compressor is replaced for noise,
vibration or insufficient cooling concerns.
• The compressor mounting bolts, brackets or braces may be loose or missing.
• The compressor drive belt may be frayed, loose or misaligned.
• The A/C refrigerant lines may be grounding out on body, chassis or engine
components. This may allow noise and vibration to be transmitted into the
passenger compartment.
• The air flow through the condenser may be insufficient.
– The condenser fins may be bent or filled with debris.
– The space between the condenser and radiator may be filled with leaves or
debris.
– The cooling fans may be inoperative or not performing as designed.
– The installation of aftermarket accessories may alter or restrict the air flow
through the condenser.
• Inspect for missing or mispositioned air deflectors, baffles, seals and
shrouds.
• The compressor cycling switch may not be operating correctly. This may allow
the evaporator core to freeze up or the compressor may not stay engaged long
enough for proper system pressures to develop.
• The air flow through the evaporator core may be restricted.
– The cabin filter may be plugged.
– The evaporator core may be covered with debris.
– The cowl air inlet leaf screen may by plugged.
• The A/C system may be overcharged or undercharged with refrigerant. The A/C
system charge weight can be measured with the RRR tool after a refrigerant
recovery is done.
• The A/C system may have an improper amount or incorrect type of refrigerant
oil.
• An A/C system sealer is not approved for use in GM vehicles.
• The vehicle’s refrigerant may be contaminated or contain an excessive amount
of air. The vehicle’s A/C system may have been charged with an unapproved
refrigerant. The refrigerant identifier on the ACR 2000 should alert the
technician to these conditions.
• The orifice tube or thermostatic expansion valve (TXV) may be restricted,
plugged or inoperative.
• The capillary bulb on the TXV must be properly positioned so that the valve
will provide proper refrigerant flow.
• The desiccant bag in the accumulator may have failed, allowing debris to
circulate in the A/C system.
• The A/C system charge weight may have been changed. Components with an updated
design may have been released. A check for service bulletins applicable to the
vehicle being worked on should always be done.
• A check for diagnostic trouble codes in all the control modules on the vehicle
should be done. Some trouble codes will disable compressor operation after they
have set. They must be repaired and cleared before compressor operation is
allowed.
• Verify that the engine is not operating with a low unstable idle, and that the
engine is operating within the compressor engagement parameters (for example,
the engine may be overheating or it may be too cold for compressor engagement).
• The diagnostic procedures in the HVAC section of the service manual should be
performed as written to prevent the misdiagnosis of a customer concern. The HVAC
Diagnostic System Check and the A/C System Performance Test are written for a
specific model only. They are not generic charts. They follow a logical order
with detailed instructions on how to perform each step.
• The Technical Assistance Center may be contacted for additional help and the
latest information on any unusual concerns.
When a thorough HVAC system diagnosis indicates that the compressor should be
replaced, follow the procedure in the appropriate service manual. The oil
balance instructions are an important part of the replacement procedure. The
correct refrigerant oil, as listed in the service manual, must be used in the
new compressor. It is recommended that a suction screen filter be installed on
Delphi Harrison compressors that do not already have one. The suction screen
filter is not approved for use on compressors from other manufacturers. Refer to
Corporate Bulletin Number 01-01-39-003A for more information on A/C suction
screen kit repair recommendations and procedures. If the compressor has had a
catastrophic internal failure, an inline filter may be required to capture the
large amount of debris that may be found to be circulating in the A/C system. In
addition, the A/C system may require flushing. Refer to Corporate Bulletin
Number 01-01-38-006B for more information on flushing procedures and
recommendations.
The addition of fluorescent refrigerant leak dye to the A/C system is
recommended if the vehicle does not have it installed already. Some vehicles
have leak dye installed at the assembly plant and this will be indicated on the
A/C charge label. Refer to Corporate Bulletin Number 00-01-38-009B for more
information. If leak dye has been added during a previous repair and has been in
the vehicle for more than three years, it is recommended that additional dye be
added. Finally, a leak check of the entire A/C system should be performed before
the vehicle is returned to the customer.
Courtesy of General
Motors.
| Pressure testing using oxygen free nitrogen. |
| Pressure test using
oxygen free nitrogen to 150psi. To find leaks in the system. When the vehicle air conditioning system is found to be empty i.e. no pressure, then a high pressure test using oxygen free nitrogen is carried out. The system is filled with nitrogen to 150psi and left for 10-20 minutes. If there is a drop in pressure then a leak in one of the system components can be located. This is done by sound i.e escaping gas, leak detecting liquid on the joints i.e bubbles forming. DO NOT USE COMPRESSED AIR to test for leaks. Even a system without refrigerant will still contain oil. Oil and compressed air = possible explosion. Refrigerants can be re-charged into the system with a dye, which will be visible under ultra-violet light. Next time the vehicle is serviced any leaks can be detected. |
Updates
May 2006
Acura Tech Tip: Radiator or Condenser Fan Operates Continuously
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If the radiator fan and/or the condenser fan of the vehicles
listed below runs continuously; or, if the fan's) runs
continuously when the engine is off, the battery may be
discharged.
APPLIES TO: 2000 3.2 TLs – from VIN 19UUA5...YA000001 through VIN 19UUA5...YA057139; and 2001 3.2 CLs – from VIN 19UY4A...1A000001 through VIN 19UYA4...1A015025. PROBABLE CAUSE: The radiator and/or condenser fan relay has failed. CORRECTIVE ACTION: Replace both relays. If one relay fails, you must replace both. PARTS INFORMATION: Relay assembly (two required): P/N 39794-S0K-A01. DIAGNOSIS: • If the battery is discharged, and there is no apparent reason, remove the radiator fan and condenser fan relays from the under hood fuse/relay box, and shake them one at a time. If you hear a rattle coming from either relay, go to the Repair Procedure. • If the fan's) runs continuously with the ignition switch off, install known-good relay's) and verify that the fan's) stops. If the fan's) stops with the known-good relay's), go to the Repair Procedure. Note: If the coolant temperature is high (above 185° F) when the ignition is switched off, the fan's) will automatically run for about 15 minutes. • If the battery is discharged and the relay's) are OK, troubleshoot other causes. REPAIR PROCEDURE: 1. Remove and replace the radiator fan and condenser fan relays in the under hood fuse/relay box. Refer to page 10-15 of the 1999-2001 3.2 TL service manual or page 10-13 of the 2001 3.2 CL service manual. 2. Turn off the A/C, start the engine and let it warm up. Make sure the fans cycle on and off when the engine reaches normal operating temperature. Technical service bulletin courtesy of Acura Parts Express. |
Updates
April 2006
USE IT - OR LOSE IT.
Operate the air conditioning at least once a week to keep the compressor shaft
seal lubricated. Failure to do so will result in the shaft seal drying out.
Shaft seal replacement is fairly simple but the compressor has to be removed
from the vehicle and the A/C system evacuated and re-charged when the compressor
is re-fitted. A costly exercise when switching the A/C on once a week will help
to avoid the seal drying out.
Use the air conditioning in winter together with the heater to reduce the
humidity within the vehicle.
Safety Switch
The safety switch is one of the most important yet
most overlooked
portion of the air conditioning system.
The function of the safety switch is to monitor high and low side pressure and
shut down the system if the pressure exceeds safe or drops below operating
limits.
The binary switch simply splices between the compressor clutch and
evaporator thermostat and taps into the high pressure line.
When pressures exceed safe limits, the switch opens the circuit to the
compressor clutch thus disengaging the compressor until pressure return to
normal.
The trinary switch operates much the same as the binary in that it shuts down
the compressor when pressures rise. However, the trinary also controls an
electric fan on the radiator that pulls additional air across the condenser to
bring pressures down.
Anti-Bacterial
The intrinsic nature of the air conditioning operation means that fungus and bacteria can build up on the internal evaporator of the car (situated under the dashboard).
This build up of bacteria can result in what is commonly known as "sick car syndrome". Not only is an offensive smell given off whenever the air conditioning is switched on , but occupants can feel sick or contract ear, nose and throat infections from your system.
The potential for streptococcal infections from contaminated Air Conditioning systems has been recognized for years particularly in California where the infection occurs all year round and is widely referred to as strep throat.
We treat the evaporator with a specially formulated Air Conditioner anti-bacterial spray that kills all the bugs and leaves your air conditioning smelling sweet.
