A/c Shield

[Dale S.]

Re: A/c Shield

My 67 A/C car has never had a shield on the compressor. I just went out and looked and I have no oil film on the hood above the compressor that I can see. Is this oil visiable to the naked eye? I start my car once a month and turn the A/c on and let the car warm up. The front seal on the A/c has never been changed. Pete Lindahl has seen the car, could you also comment Peter. Thank you in advance Dale

[Tom L.]

Re: A/c Shield

The oil control systems in refrigeration-A/C (RAC) and engines are very different. In an automotive engine oil is intended to remain out of its combustion and intake areas. However in a RAC oil IS intended to travel throughout the system and is done through it's ability to blend with and be carried by refrigerants. Older oils were mineral oils, 134a and many others will not blend with those oils, hence the reason that they are required to be changed when changing refrigerants. If there is a mismatch of refrigerant and oil the oil will be pushed out of the compressor and will not be able to return the oil back to the compressor resulting in the same types of failures as an engine running without oil.
I certainly do not doubt that you witnessed oil being seperated and stored seperately on a recovery machine, however those machines are intended to remove refrigerant, not oil. The oil was simply carried out with the refrigerant and seperated so the refrigerant could be re-used or recycled..