expansion valve question

[manta928]

I own a 1982 Porsche 928 and i have a bad expansion valve for the air conditioning system. Can anyone tell me where it's located and how hard it is to replace?
Thanks

[neil30076]

Originally Posted by manta928

I own a 1982 Porsche 928 and i have a bad expansion valve for the air conditioning system. Can anyone tell me where it's located and how hard it is to replace?
Thanks

How do you know its bad? - anyway -under the black cover at the rear of the engine - up by the wiper mechanism - maybe someone else can tell you wants involved in replacing it - an a/c purge and refill at least is my guess.

[manta928]

I am compleatly full with freon but when I turn on the air it only blows warm. It was a house air repair guy that told me it had to be the expansion valve that was the problem.

[stepson]

It is possible that your expansion valve is defunct. However, before you start replacing it, check your vacuum system. Is the hot water valve at the rear of the engine closing when you start the car? Does it remain closed? Is the fresh air footwell flap under the A/C blower and above the passenger footwell closing completely?

Check these things first. They are much easier to check BEFORE changing out the expansion valve.

[neil30076]

^^ what John said ^^ PLUS
I would not let a Porsche mechanic work on my home a/c, and a home a/c guy is not an expert on auto a/c!

[Niles]

Another common failure is the relay on the A/C control head. Everything will test okay, but when you turn on the AC, the air conditioning compressor clutch does not engage. The relay will handle the amperage required by the switches, but not the amperage required for the clutch.

[AirtekHVAC]

When you turn on the ac, does the compressor run at all? Lots of othern easier things it could be.

[harborman]

Originally Posted by AirtekHVAC

When you turn on the ac, does the compressor run at all? Lots of othern easier things it could be.

From what I have read on here, there seems to be many issues with the heater valve not closing, vacuum problems with controls, vent flaps, etc. I think there is a bank of vacuum valves that needs to be checked also, inside the center console. There is a nice write up on Rennlist on trouble shooting the AC. Check that out.

[MPDano]

The AC shop replaced my EV on my Euro. It's also a bear to get tools in there. They ended up cutting mine off. I traced an electrical short there as anytime I used my blinkers, it would blow a fuse. The AC shop smashed a couple wires and shorting them. I would get a second opinion on the EV, but also have them do it if it needs replacing. Neil, the compressor you gave me is still running strong on the Euro

[harborman]

Look this up:

Porsche 928 email Keepers

[JK McDonald]

Hey Manta928 - You should do a thorough search on the 928 A/C system before replacing any components. I agree with Neil when it comes to letting someone make a "shoot from the hip" troubleshooting suggestion on a 928 without an extensive knowledge of the vehicle.

The A/C system is not terribly difficult to understand but there are definitely a few specific areas to check and verify well before replacing the expansion valve. Keep us posted on your progress.

Good Luck, Michael

[Mrmerlin]

FWIW if the AC system was empty for any period of time its also quite possible to have the EV become plugged from corrosion thats usually why they get replaced.

For now it would be good to evacuate the freon so you dont lose it.

Replace the EV and the receiver drier,
and all of the O rings in the system , after it has been flushed.

NOTE flushing after installing new O rings will usually damage the new O rings.
So flush it prior to new O ring installation

EV is under the cowl cover follow the heater lines they run next to the EV.
The RD is at the front of the engine bay its the round tube looking thing with a sight glass,

install the RD last,
then evacuate the system,

make sure to also replace the 2 hoses that come off of the compressor as these usually leak , you can have the hoses remade and use the old fittings.

Also replace the 4 O rings that seal the compressor manifolds to the compressor body.

Carquest makes an A/C O ring kit that has about 35 O rings in it,
you should be able to do the whole system with this kit the O rings are green.

[manta928]

Thanks for all the responses. Yes the compressor turns on. There is a problem with the vents, they will always blows air from the outside when driving even when all the controls are turned off.

[Mrmerlin]

Please read this it will familiarize you with the HVAC system before you spend any more money

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&sqi=2&ved=0CEsQFjAA&url=http%3A%2F%2Fwww.928gt.com%2FT-WallyHVAC.aspx&ei=tNNxUdPTDs_vqQG94YCAAg&usg=AFQjCNELPje_Z70T6sJEBQqPzEyL0qCDLA&bvm=bv.45512109,d.aWM&cad=rja

[JK McDonald]

Great Information MrMerlin - I tucked a copy of this away in my 928 DNK (Did Not Know) Files for myself..... The condensed information on the later 928's will be a nice addition to have on hand.

A couple of years ago a buddy had turned his 89 S4 over to an A/C shop for a minor system recharge. Finally, two weeks later he was handed a $2,889.55 repair bill. The worst part was that the new compressor failed shortly after the warranty had ended. He said that he was limping around a bit after paying off that one......

The next time around with some help from the 928 sites, he did most of the leg work himself and replaced the needed components. After a professional evacuation/recharge of freon everything was blowing cold again. The total bill this time around was $478.....

Good Luck Manta, Michael

[Danglerb]

Pelican sells a 134 conversion kit that I think includes all the orings.

[MPDano]

Originally Posted by Danglerb

Pelican sells a 134 conversion kit that I think includes all the orings.

Lotta extra cost and conversion pieces if he just needs o-rings. I told 928 Intl what I needed and they sent just the proper o rings. Was cheap too. Pelican might be able to do the same.