A/C blows warm air

[kcoyle]

Another noob question. I am still looking for a 944 NA and in almost all of the ones I've come across so far (about 5) the owners tell me the same thing, the AC blows warm air. The 2 cars that I saw the compressor kicked on. I tried to do some searching and couldn't find a "smoking gun" answer as to why.
Is there one or two very common problems or are there all kinds of things to go wrong, and what is a ball park figure to get it working again assuming (i know, i know) that compressor is good?

Kevin

[Grandad#3]

Hello, Check out the link below for Heater Operation and DIY Maintenance. Clark's garage.com is where you need to become familiar with for any maintenance. Broken plastic clips next to and above the drivers right foot area directs full heat at all time. It was designed to fail to the full heat position in winter.

944 HVAC Operation and Malfunctions

Clark's Garage Home Page

Cheers,
Larry

[LUFTMAN]

See if water valve closes at firewall area does lever move back and forth to shut off water. If not check for vacum at valve.

[John_AZ]

"smoking gun"
Compressor front seal. If you see old oil and grease buildup in front of the compressor the front seal is bad.

If it is just the seal, you can get the compressor resealed. OR get a rebuilt.

If you convert the system to R134a correctly, your cost will be about $300 if you do the work and have a decent vacuum pump.

Prices will go up if you take it to a shop and pay for labor---double/triple ????

You can get a complete updated AC kit for about $500.
Here is a link on installation:
A/C Retrofit - Porsche 951 - www.texasblake.com

GL
John

[wild man]

Welcome to the hot A/C club. If you want, there IS a "quick and dirty" (cheap) way out of it:

Bleed out any residual pressure, and vac it if you have the means to. Put a can of ester oil (NOT PAG) in it (through the LP port, near the comp), followed by 4 cans of R134a. Then asses how long it remains cold. If it doesn't last the summer, the shaft seal on the comp probably needs to be replaced. But be sure to check that the valve cores are tight. I did have an issue with that. Now it holds charge for a lot longer than it used to.

[John_AZ]

wild mans "quick and dirty" R134a procedure is for the most part a good way to test a system on a car that you have no information on.

Early 944s will make it difficult to charge the low side because it is hidden under the compressor and you have to change the valve to a 90 degree style.

R134a works the best when you only install 75 to 80 percent of the OEM AC capacity. So if the sticker on the wheel well say max R12 ---33 oz, you would get the best cooling from R134a with about 28 ounces of R134a.

I put 2-12 oz cans in my '87 924S and it is fine for hot AZ temps of 100 to 110 degrees.

Ask the owner when the AC quit. If it has been sitting in a field for 3 to 5 years, you costs will really go up with dried out seals and parts.

GL
John

[kcoyle]

Thanks for the great info. I'm looking at the car tomorrow, its an 88 that was supposedly sitting for a year.

This is critical to me since A/C is on of the main reasons I'm looking for a more modern car.