Heater Valve - Where is it located & A/C Question

[Tidybuoy]

I just had the A/C serviced. The car has been in storage for 6 years and so the freon had all leaked out.

The mechanic charged the system but told me that the climate control is cycling back and forth from A/C to heat and back. He said it will require further diagnosis to find the culprit but since I needed my car back, I didn't have it fixed.

He told me that it could be the internal temperature sensor, external temp sensor, heater valve or other.

I thought I would replace the heater valve and maybe the internal temp sensor to start (that's probably cheaper than having the shop diagnose anything). And, if that does not fix it, I will return to the shop.

So, where is the heater valve located.

Also, what is the device that is located on the driver side fender next to a diagnosis port that is some type of valve and it connects up to the vacuum line going to the charcoal cannister?

Any advice would be great............................Vern

[JRMock]

The heater valve is located at the back of the engine, between the head and the firewall. It is a real pain to get to.

It is just a plastic water valve that opens up to let hot water into the heater core. What usually happens is the cable connecting the interior control to the valve breaks, leaving the valve in its last position. Typically, it breaks with the valve open, and you get heat all the time.

Not sure which device you are referring to on the fender well, but the charcol canister is to trap fuel vapor from the fuel tank vent.

good luck,
JM

[Tidybuoy]

Thanks.

I may post a pic of the divice I'm looking at on the fender. I thought that was the heater valve but it would make no sense to to be hooked into the vacuum canister.

My heater valve does not stick on. but the heater turns on and off at random (including the fan turning on). Maybe it's not the valve at all but the interior temperature sensor...I guess I'll find out someday.

[HondaDustR]

Isn't the heater valve relocated towards the front of the engine on the 88?

[SoCal Driver]

And it uses vacuum rather than a cable. Check above your gas pedal and see if there isn't a broken of loose link on the heater box. Could also be the climate control unit. The one in the dash.

[Razorback1980]

The part on the fender you are referring to is a valve for emissions control and I don't remember anyone having to mess with that.

Here is a link to a web site that shows you how to check the linkages that SoCal mentioned. It's very common for the plastic clips to break on these cars. I've replaced them on both my 944s.

http://www.kronowit.com/porsches/944-heater-fix.html

[67l60]

razorback that is a very good link + i found the complete parts catalog on his site , for free i download it and thats a score if you guys dont have a copy
i d get one

[SoCal Driver]

You can get basically the same PDF on the Porsche web site. Might want to check there and get all of the 944 and 924 variations parts catalogs.

[Tidybuoy]

Thankyou Rasorback!

That link explains it all - guess what I'm doing this weekend?

Vern