DZGunner

sinse we are talking about this conversion, i was just wondering if when switching to 134a, if you have to change to PAG oil instead of mineral oil. Or if you can have mineral oil in the system with 134a. Thanks.

Rob Edwards

Kevin- I dunno, those hoses look pretty original to me- I'd wager the 40/89 refers to 40th week of 1989 manufacture. And fittings and texture of the hose look identical to what I've seen on '90 and '91 cars.

I don't see any reason these wouldn't fit together on an '87, the only thing I wonder is whether the routing of the pressure hose around the end of the radiator into the condensor was different between '87 and '91, since the compressor changed.

The other thing- A 5-speed condenser is different from an 'automatic's condensor, not sure what tranny your '87 has. Might be an issue.

Here is a crappy pic of new factory '90-95 suction and pressure hoses to/from the compressor. Porsche didn't make r134a-specific hoses for the late '93-95 cars, they're the same part numbers as for the 90-91's. They apparently didn't care about barrier hoses (?)

alabbasi

Ester oil is compatible with both systems and should be used for conversions.

WallyP

Use PAG oil only if the system has never contained mineral oil. Basically, this means systems with R-134a from the factory.

Use POE oil for any conversion from R-12.

Kevin in Atlanta

Thanks Rob - I am always learning new things on this list. Both vehicles are manual and apparently converted to 134a. Since I am replacing condenser, hoses, etc I think I should be ok. I have a new receiver/dryer and expansion valve on the shelf. And I also have the a/c compressor from the 50k S4 on the shelf - so I think I am covered. Need to order the o-rings this week.

When I did this on my 86.5 I used several cans of brake kleen to clean all the lines, compressor and the condensor with good results. Maybe I will use mineral spirits this time.

Thanks for everybody's input.

Kevin in Atlanta

Wally, does that hold true if you flush out the system after it was converted to 134a?

The Forgotten On

Still holds true.You need to have under 2% of contamination from mineral oil in order to use PAG oil. POE oil is much more forgiving.

Kevin in Atlanta

Thanks and noted.