dave944

I am looking at a 90 944S2 - the only thing I can find wrong is that that a/c needs re-charging - is this a big deal?

MadMax

It depends. The only reason for a need to re-charge is a leak. If the system hasn't been converted over to R-134a refrigerant it still uses R-12 (~$40-$50USD per 2.2kg). The average system contains approx. 6.6-8.8kgs of refrigerant. As you can see that can get very pricey. My advice, for what it's worth, don't recharge with R-12. Spend the money to convert to 134a and then recharge. It will end up costing the same and in the future, recharges/service of the A/C system will be much much cheaper.

Even if there is nothing wrong with the A/C system (except minor leak)seller should come down at $200 USD for the R-12 cost.

IMHO,
Max

TomH

MadMax, I thought I read in Haynes, or maybe Excellence that the various hoses in the AC setup actually had very small holes in them that would cause leakage over time (designed to leak, vs. blow off). I know this sounds strange, which is the same thing I thought when I read it. I'll see if I can't relocate the source.

Anyway, just had my AC recharged by dealer, and they couldn't find any leaks. So they either charged me for coolant I didn't need, or it it did escape, and was low.

MadMax

Tom,
I'll have to look in my Haynes manual too. I was not aware of that. It doesn't make much sense to me. Freon is an inert gas and it fairly dense. It doesn't make sense to design a refrigeration system that purposely bleeds off the refrigerant. In truth all refrigeration systems leak (a little bit), meaning they need a recharge (partial recharge 10-20% of total coolant volume) every 2-3 years depending on use. Automotive wise that is. This usually due to seal deterioration due to non-use. If you ran your A/C everyday it would most likely stay charged longer and the compressor would last longer. Not being used is kills a compressor and system pressure fittings faster than anything else.

I hope you find that section in Haynes. I'm curious now.

Max

Tom Pultz

FWIW, Freon costs $69-80/lb in the Seattle area. If you can find it for $40 that's a bargain. The 944 uses about 30 oz, which is a far cry from the 211-310 oz (6.6-8.8 kg) you quote!

While I have not personally seen any A/C system in a 944 that has been converted to R-134A I find it hard to believe it could work as well as R-12 since R-134A is not nearly as efficient as R-12. In order to get the same cooling from R-134A you need a much larger condenser. There may also be issues with seals and hoses. R-134A systems typically use barrier hose because the molecule size is lower and it will leak through normal R-12 hoses.

Most A/C shops probably do not do the conversions per the Porsche Technical Service Bulletins. To do the job correctly is time-consuming since multiple evacuations are required to extact the old R-12 compatible oil. I would be very leery of any shop doing a conversion unless they could prove to me they knew what they were doing.

I think conversion to R-134A will eventually become inevitable as supplies of R-12 dwindle and the price sores even more than it already has. That doesn't mean all systems should be converted now if all they need is a pound or two of R-12 to function normally.

Tom Pultz
1990 944S2 Coupe

MadMax

Oops! Bad math on my part. I converted lbs/kg incorrectly. I applied 2.2lbs to kg to the kilograms rather than the pounds. I was trying to say 3-4 pounds of R-12 which is what many 70's and 80's domestic cars have. Sorry for any confusion I might have cause, including to myself. Thanks for pointing that out Tom. Love your website by the way. Nice brake job and info on the Koni struts.
I'll be quiet now.
Max