A/C - System Sporadically To Cool
SI B64 21 06Heating and Air Conditioning
December 2006
Technical Service
SUBJECT
Air Conditioning Sporadically Fails to Cool
MODEL
E46 (3 Series)
SITUATION
The customer states that while driving, occasionally the air-conditioning system stops cooling
CAUSE
The suction hose (compressor to expansion valve) has internally separated. Analysis of collected hoses indicates that the incorrect refrigerant oil (POE - Polyolester Oil) was used on a previous repair causing the hose to internally separate.
PROCEDURE
1. Verify customer complaint on test drive.
2. Review repair history for previous air conditioning repairs.
3. Check the system pressure when the complaint occurs. Low-side pressure will be high and High- side pressure will be low.
4. Eliminate all other possibilities as the cause, i.e. compressor belt, system charge, electrical operation, etc.
5. Check for proper refrigerant oil in the workshop as outlined in the Operating Fluids Manual (PAG-Polyalkylene Glycol lubricant is the only approved oil for R134a systems.
6. Evacuate and recharge the system several times to recover as much oil as possible.
7. Replace the suction hose (hose between compressor and expansion valve). Refer to EPC for correct part application.
8. Replace the receiver/dryer unit. Refer to EPC for correct part application.
9. Discard the recovered oil and replace only with PAG oil.
WARRANTY INFORMATION
If the incorrect oil is used, this is not considered a warranty matter.
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