Robin 993DX

oh............. Forgot to mention....I was referring to my 996.

My 993's A/C still sucks big time.

donsacto

Robin:

Interesting observation. I feel the 993 AC is adequate for the 100 degree heat in the Sacramento Valley. Now talk about inadequate AC, that would be my former BMW M3; the fan speed on that car was horrible. How hot does it get in Chino?

Robin 993DX

I have been fighting an A/C problem with my 993 for two years now. I have done everything that I can think of, Several A/C specialists, even the dealer. Still no fix. Basically it just doesn't blow cold, the A.C. Compressor cycles on and off too often and there is as stuck fresh air valve which sometime would block the flow of the air ( I can make a quick fix if I push on/off the A/C button enough times). The main issue is still that somehow the compressor is cycling too often. Dealer thought was because I overfilled the A/C system, but ever after paying $450 to release the freon the A/C still doesn't blows cold. In any case is a lost cause.

All this happened after I left my car sat for 6 month and somehow all the freon leaked out of the system. It never worked correctly after the refill.


Chino hills gets about 80 degrees, forecast says 90 today.

In the 996 the A/C gets so cold that I actually have to crack open the window a little to let some warm air in.

Texas993

My first thought when I read your string title was "something must be broken!". Living in the desert, I never felt the 993 A/C was enough. If ever you parked it in the sun; forget about it cooling off. But I am talking about extreme desert heat over 110.

InTheAir

Perhaps there is something here that can be useful:

http://www.griffiths.com/porsche/ac/ice/index.html

ZombiePorsche44

I guess I got lucky Robin, because my 993 is the only Porsche that I have ever owned that the A/C actually worked in.

My 80's Carrera blew hot air on cold settings and hotter air on any other setting. It was easier to rip it out and save the 52 lbs* off the back of the car.

ZP44

*(inc all hoses,fittings, evap, compressor & condensor)

texas911

My 993 blows cold, but blows colder when I'm moving. That said, the 997 literally blows away the 993 interms of a/c. Quite satisfied with the 993 a/c though.

Robin 993DX

Well... the A/C in my 993 used to blow cold even in the humid S. Florida weather. But not anymore.....

p_carfan

Yep....sort of a pisser. My Toyota Tacoma on it's very first setting will freeze your a$$ off and the 993 at best is barely adequate

tj90

Robin - as you know I replaced the evap in mine and its still blowing cold. (Please PM me your email so that I can send the word doc of the DIY to your email). With that said, my other cars are colder than the 993. If you have access to a thermocouple, measure your vent temps and see if it is within spec according to porsche. Mine is within spec but still feels warmer than my other American steel cars. I noticed that with the new expansion valve that I replaced with the core seems to cycle on and off alot (its a momentary hiss every few minutes). I have heard of other complain about their evaporator freezing up so Im not complaining that the expansion valve is doing its job and preventing a block of ice from forming around the evap rendering the AC useless. Maybe your expansion is working too well.... Maybe you need to adjust / replace expansion valve - easy to do when the gas tank and firewall are out.

I have noticed that my AC works better when Im at higher RPMs casuse the compressor is spinning faster.

Mark Wilson

Just replaced the compressor in my 97($430) and had an evac/refill this morning($122). It's blowing very cold. Have to check vent temps this aft when it's over 90.

Robin 993DX

TJ,

I think my evaporator core is still in good condition as my freon level is holding. I thought about replacing the expansion valve and the dryer, have all the parts. But the thought of taking out the gas tank turns me off.

Thanks for the offer, I will PM you.

slant911

Robin,

Have you considered your CCU? In my previous life with a 90' C-4 I had all kinds of weird issues icluding weird A/C problems that all but went away with a replacement CCU. Just a thought.

tj90

Robin - dont be too concerned about dropping the gas tank. Seriously, firewall and gas tank can be out of your car in an hour. The hard part of the expansion valve is that you will have to open the system and reevacuate and charge your system. If you dont have access to vacuum pump or manifold guages, I would be happy to assist you in this DIY.

tj90

The nippon denso compressor on your 993 is different than most cars. The AC shop will generically add freon until you hit 20-30 psi on your low side. Porsche compressors only require 12-15 psi. I know that the dealer went down this path already, but it would be worth you to buy an AC manifold and monitor your PSI on high and low side when you experience the cycling issue. I say this cause it would guarantee that the dealer put the right amount of freon in the system. Manifold guages are cheap at harbor freight....

When I first started playing around with the 993 AC, I added too much freon (following recommendations from the back of the recharge kit from the parts store). Only until I read the porshce tech manual did I realize that the porsche compressor has lower psi on the low side of the compressor. When I added too much freon, my compressor cycled too much.

Must figure out why the compressor is cycling..... You can bleed off the freon with the manifold guages and recharge with new r134 to replace what you removed for a few bucks / can. It would be interesting to try this and see if the compressor acts differently.

Let me know if you need to borrow the manifold guages, I will be passing by your area on Saturday on my way to Fontana for porsche racing. I would be happy to briefly take a look at the car.