924Board.org

[the4ork]

seems like the heater is weak as hell... like the weakest ive ever seen on any car. the heater core is definately getting hot, but the fan seems to barely blow...

i popped the hood open with the fan on and its going pretty good, but i dont seem to get very much flow when switched either at the feet or at the defrosts in the dash...

also, the heater air does not blow out of the regular dash vents ive noticed... after several minutes of adjusting the levers in every which configuration i could think of...

[flosho]

haha.. I've never really been able to figure out the levers.. just that all of them to the right is good to defrost my window. Now I'm missing some of the vent ducting, so the heater is even more worthless..
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1981 Porsche 931 -- "Escalation of Commitment"
-Megasquirt 1v3.0 EFI/EDIS conversion, 250# springs, 17" turbo twists, 26.8/18 sways

[Harm]

[the4ork]

everything seems to be working correctly... even the connections...

i "jumped" the fan with some wire straight to the battery and it doesnt seem to come on any faster... its just a crappy design it looks like. the fan in my MK1 is a jet intake type fan, while the one in the 924 is more like a small radiator fan with fins and all. the one in the mk1 is just a giant cylinder with paddles in it (im assuming the later porsches went to these as well)

dissapointing. and yes the damn lever isnt opening the valve all the way. it may blow warmer air now but its still a weak fan design

[BionicBalls]

the early style fan setup is just that bad. I replaced my heater fan, and all of the cables. I also resealed all of the connections under the dash when I did my recover and my car still feels like it's leaking hot air rather than blowing hot air.

I will be upgrading my setup to the later style "squirrel cage" this winter. I believe there is a write up in the how-to section if you're interested.
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1980 924 NA
1982 931

[Elektrobank]

[BionicBalls]

http://www.924board.org/viewtopic.php?t=21849
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1980 924 NA
1982 931

[Harm]

[flosho]

[Smoothie]

One design problem with the early hvac system is it doesn't route heated air through the chest-level rear-facing dash vents. They only provide unheated air from outside, so you'll want to close them for the winter. Only the defrost and foot-level openings provide heated air.
This was changed with the later design, so the later cars get heat from all vents.

Another possible cause of low heat is a clog near the heater core. My car (even with the later hvac) had weak heating. I found the problem after driving around cold for a few years - when I finally flushed the system, a plug of the previous owners' radiator stop-leak shot out of it, and the heat's been more than adequate since..
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"..it's made in Germany. You know the Germans always make good stuff."
- shamwow guy

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[ZODIAC]

Scorpio brought up this idea awhile back. i think when the time comes(after i tacke the whole getting her running thing ) i might go this route. relatively inexpensive, and i dont have a/c anyway so having only heat wouldnt be a bad thing. i think the 3 speed versions would be best, but 2 speed isnt bad.
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"Kraut cars, they know how to build 'em".
1977 924 N/A - Red with waterdamage interior
yes...waterdamage is now a color...

[Slam]

A word to the wise: rebuilding/refreshing your heater to factory specs in these early cars is a waste of time and money. I just did Mandy's (I can post a plethora of pics if you'd like to see them) heater back to factory stock specs in her 1980 924 - rebuilt and resealed the heater box, had the core flushed, put in a new blower, changed the thermostat and it still absolutely sucks. It's the worst heater I've ever met. I still have some experimenting to do on it to see if I can't improve it, but it seems to me the whole design concept is fatally flawed. All that remains is to drive up engine temps, remove and flush the coolant transfer pipe and change the heater valve. But what a PITA.

My point is that instead of focusing your attention on what's in the dash, suss what's going on under the hood, a la Smoothie's post.

But here's a mystery: her 77.5 California-spec slushbox beach-car jalopy 924 had a heater that seemed to work much better...
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'84 924 Euro - SOLD!
'83 944 - still looks like ass, still runs like horse.
'80 924 - ex-Chrenan yellowjacket.
'80 924 - resto for offspring.
'77.5 924 - out there, still alive.
'78 924 - redneck dirt racer
Some wrecks.

[bnoon]

I had a friend in high school that had an 80 931 back in 1987 and it sucked back then. By the time we got to school, we could just about take off our gloves after a 20 minute ride.
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'80 924 Turbo (931)
928 S4 wheels 16x8 et 52.5 245's rear 225's front
944 spoiler
Project car log

[Smoothie]

For your entertainment - my cartoon of the early hvac box.. You can see where the air is sourced for the rear-facing dash vents, and why it's not heated.


More detail on the clog that'd rendered my heater useless -
It was located at the heater valve at its' upstream side. The heater valve, when closed, still leaves a small opening for a trickle of fluid to flow through. The stop-leak did what it was designed to do and built up at that spot, dealing with the closed heater valve as if it were a leak. I'm pretty sure the early hvac would be subject to build-up and blockage at the same location if a rad stop-leak product was ever added to the system...
Extra-long needle nose pliers like these make dealing with the heater valve and its' hoses easier -

_________________
"..it's made in Germany. You know the Germans always make good stuff."
- shamwow guy

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[1979*924]

Where exactly is the lever (#15) located? I have to raise and lower the shut off flap (#14) by hand.