Automotive Air Conditioning Information Forum (Archives)

Mulder on Mon April 30, 2012 2:52 PM

Year: 2000
Make: Chevrolet
Model: Impala
Engine Size: 3400
Refrigerant Type: 134a
Country of Origin: United States

I'm getting ready to replace the compressor shaft seal on a V5 with a new double lip seal. I read in the tips section that the seal should be soaked in mineral before putting on the compressor. I just wanted to know if it matters if it is soaked in mineral oil or pag oil or even vacuum pump oil.

I'm asking because I already have some pag oil but couldn't find any mineral oil locally. I found places that could get it for me but it will run about $10 and I really don't have any other use for it than to soak this seal. If it's best to use the mineral oil I'll do that rather than risk failure but I wanted to know before I make the order.

GM Tech on Mon April 30, 2012 9:11 PM

I've replaced over a thousand shaft seals, V5, H6, A6- whatever-and have never soaked seals-- they go in at the factory with just mineral oil smeared on the teflon and on the outer diameter where it seals against the o-ring. I also drip some oil on the shaft seal protector tool that slips over the shaft threads and keyway - then I rotate the seal ever so slightly as I push it down over the tool- and always listen for it to seat properly.

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Mulder on Tue May 01, 2012 1:59 PM

Thanks for the reply. So no need to soak, just coat the seal and the shaft seal protector.

But does it matter if I use PAG vs mineral oil?

mk378 on Tue May 01, 2012 3:36 PM

PAG oil shouldn't be used externally since it absorbs water and promotes rusting. Small quantities of a suitable additive-free mineral oil can be bought at drugstores. It is used to lubricate the insides of old people.