ideola

I just acquired a 1980 928 Euro. I'm flying out Friday to CA to drive it back to MI. According to my brother, who picked up the car for me, the internal heater control is stuck and won't stay in the "warm" position. Any suggestions on what to look for? Is it possible that that heater control valve is stuck, preventing the slider from moving? If so, is the heater control valve easily accessible in the engine compartment?

Sorry I can't describe it any better. I'm not familiar with the layout of the 928, and I won't be able to physically examine the car until I arrive in CA on Friday. I will have about a day and a half to figure it out and try to fix it before we start driving back. Thanks in advance for any suggestions.

Jim bailey - 928 International

The heater valve is held closed by vacuum and fails defaults to the open position and hot water circulates ALL THE time. It is under the air cleaner housing at the rear of the passenger head odds are it has been wired shut at some time in the past. The early heater controls (manual temperature) use a lawn mower throttle cable and a vacuum manifold to adjust /mix air. If you open up the heater valve you will have hot water all the time unless someone has put a plug inside one of the heater hoses or some such thing. The odd looking bolt at the back of the intake center plenum must be removed in order to get the air cleaner housing off on a 1980 Euro. I suggest you have my phone number handy in case you have difficulties on your return trip because there are few 928 parts between California and Michigan..........

SharkSkin

It resides under the air cleaner and it's much more common for it to fail in the "warm" position. When vacuum is applied the valve should close. What you are describing sounds like it could have the wrong vac line attached or the valve itself is stuck closed. There should be an orange line leading to the valve from the firewall. Other possible causes... the heater core may be clogged or bypassed(or both).

Did the 80 have the "climate control" where you set the temp on the slider? If so then I think there may be another series of things that could cause this but I'm a bit foggy on the details. I could look it up when I get home but very likely someone else will come along before then with more specific info.

HTH

SharkSkin

I see Jim hopped in while I was distracted.

ideola

Based on the fact that this was originally a Las Vegas car, and subsequently a Southern Cal car, I'm hoping that Jim is correct in surmising that the heater control may have been wired shut. I'm still not clear on how this would explain why the lever in the cockpit won't move...

Jim, 928 International is already in my bookmark list, as I've been doing research over the past couple of months in anticipation of picking up the car. I'll make sure to have your number handy...I may be giving you a call on Saturday when I see the car for the first time :-)

Big Dave

ideola:

I see you're from Plymouth, so when you get back into town with the car, you'll be in good company. You've got a fairly large group of owners in the area that have pretty much dealt with every repair issue. Check out this post if you're interested in getting together with some of us at our monthly "beer and wings" night...

CLICK ME!!!

Oh...just to give you an idea of how many of us there are....

CT928

I know this one!

There is a bowden cable which runs from the back of the heater control slider to a flap on the heater box. If you look up in the drivers side footwell under the gauge pod you'll see the end of it with an e-clip holding it onth the arm of the flap. It's near a vacuum actuator

The other end attaches to the heater slider by having a kinked end which locates in a small hole in the slider arm.

What has probably happened is that the cable has passed further through the slider arm then it should and been forced, which bent it. This is what happened to me.
To free up the heater slider you can remove the end of the cable from the heaterbox flap, but to fix it requires removing the whole a/c control unit. (What out for the vacuum manifold it can be a real biatch to get back the pipes in the right places if they come off)

Hope this helps

ideola

Big Dave
Thanks for the invite...I will definitely plan on stopping by the monthly meets once I have my shark in MI. I may have my son tag along in his 924 as well (hmmm....remorra, maybe???)

CT928
Sounds like a real possibility...I had this exact problem on my sons 924, but I wasn't sure how similar the mechanism was on teh 928, not having seen it in person.

The suggestions here give me a few things to look for, so I definitely appreciate the tips! Hopefully, it won't be too cold on the trip home! We leave on Friday, so I'll update everyone once we make it safely back!

ideola

Well, we made all 4000 miles from Cali to MI with no breakdowns, no tickets, and NO HEAT ... which wasn't a problem until the stretch from KS to MI. I bypassed the heater control valve, but no luck, so my guess is that the heater core is either plugged, blocked or bypassed. Since I didn't have the space or time to work on that during the trip, we did without heat ... until I finally broke down and bought a 750 Watt DC to AC inverter and a 750 Watt personal space heater. Just couldn't stand it anymore! That got us the last 4 hours home in some comfort, and I'll be able to use the space heater in the basement.

Here's some pix from the trip:




Red Rock Canyon State Park, CA


Mount Whitney Portal Road, near Lone Pine, CA


Panamint Mountains, Death Valley Nat'l Park, CA


Telescope Peak at Dawn, Bad Water Basin, Death Valley Nat'l Park, CA


Hoover Dam


Lakeshore Scenic Drive, Lake Mead Nat'l Recreation Area, NV


Self Portrait overlooking Zion Nat'l Park at Dawn


View from my side mirror at our lunch spot overlooking Glen Canyon, AZ


Four Corners (AZ, UT, NM, CO)

gruffalo

does your car have the m28/09 engine?

So does mine, it's pretty rare...

mm

ideola

Actually, yes it does have the m28/09 engine, which is kinda weird. The guy I bought it from claimed it was a Euro S ... it has all of the S appointments, including the "928S" sticker on the rear, which *appears* to be original. However, I was led to believe that the S model had the m28/11 engine, which was the 4.7L 330 HP version. Also, it does not have the S style steering wheel, nor does it have the S sill plates. So I'm thinking someone went to reasonable effort to make it cosmetically look like an S. Also note that the wheels are the OEM Porsche club sport wheels, which I don't believe appeared until '87.