No heat, no moving air, where to start please?
11-09-2018, 04:19 PM
#1
Addict
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No heat, no moving air, where to start please?
Hi folks, so this is a pretty rough 79 5 speed I rescued from the South of France..I have done a lot of work including intake, clutch, suspension - but it wasnt starting well or running right. I finally stripped, cleaned and lubed the WUR after getting some fuel pressure checks, and it is really running well now. Even only with the 4.5, such a nice car when its running - I am finally really enjoying it :-)
So, down to the next priority on the list, now that winter is here - heat and screen defrost. Currently I can hear a fan noise when I turn up the fan speed, but there is no detectable air flow - either propelled by a fan or any discernible heat, from any of the vents.
If I try to turn the temperature up, the slider wont go and it bounces back, feels like a cable is trying to operate a flap but it is stuck shut.
I know I am a loonnnng way from fully factory standard operating HVAC, but a little heat would be nice - even just to keep the windscreen clear. I have done a search but there are so many posts - can someone help with directing me to a troubleshooting post? I am not used to watercooled heating systems.
Also, specifically, I had read somewhere that a flap gets tied shut in cars from hot climates - feels like this is the case with mine, with the way the slider control is behaving, and the car coming from the hot Cote d Azur. Where am I looking for this?
Thanks as always, Johnny
So, down to the next priority on the list, now that winter is here - heat and screen defrost. Currently I can hear a fan noise when I turn up the fan speed, but there is no detectable air flow - either propelled by a fan or any discernible heat, from any of the vents.
If I try to turn the temperature up, the slider wont go and it bounces back, feels like a cable is trying to operate a flap but it is stuck shut.
I know I am a loonnnng way from fully factory standard operating HVAC, but a little heat would be nice - even just to keep the windscreen clear. I have done a search but there are so many posts - can someone help with directing me to a troubleshooting post? I am not used to watercooled heating systems.
Also, specifically, I had read somewhere that a flap gets tied shut in cars from hot climates - feels like this is the case with mine, with the way the slider control is behaving, and the car coming from the hot Cote d Azur. Where am I looking for this?
Thanks as always, Johnny
11-09-2018, 06:59 PM
#2
Team Owner
the early cars had a more or less experimental HVAC system.
The console was added to the radio and HVAC head,
this means that removal of said parts requires removal of the console first.
Then turn it over to remove the parts that are bolted to it.
Anyway they had a cable running the flaps in the HVAC unit,
if it comes loose you will loose all control of the air.
Best bet, remove both side console covers then see if the cable and the cable housing are properly attached to the HVAC head unit.
This could fix the unit and provide warm air.
The console was added to the radio and HVAC head,
this means that removal of said parts requires removal of the console first.
Then turn it over to remove the parts that are bolted to it.
Anyway they had a cable running the flaps in the HVAC unit,
if it comes loose you will loose all control of the air.
Best bet, remove both side console covers then see if the cable and the cable housing are properly attached to the HVAC head unit.
This could fix the unit and provide warm air.
11-09-2018, 10:01 PM
#3
Rennlist Member
As I recall, designers of the HVAC default it to heat if there is a problem because of the climate of Germany. I would check for rodent nests blocking the flaps in the air system since it sat for so long and there seems to be a mechanical interference in the mechanism.
Last edited by 928 GT R; 11-09-2018 at 10:20 PM.
11-10-2018, 05:33 AM
#4
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Thread Starter
Thanks, I am going to start dismantling and eyeballing stuff and will report back. I also wondered about critters, although there arent the usual signs in the cabin. My last purchase was a 911sc and that had a rodent corpse welded to the top of the transmission..In a similar vein, on this car there is a rather beautiful wasp nest under the front spoiler, that has survived the journey to scotland, so I dont have the heart to remove it just yet 🙂
11-10-2018, 01:18 PM
#5
Rennlist Member
Almost certainly have a broken tab on the head unit. There is also a metal clip that holds the cable down onto the tab. Not sure why these tabs break off but it seems to be a common problem. I got lucky and found the broken tab as well as the metal clip. Both had fallen down and got lodged in the transmission tunnel carpet. I re attached the tab with appoxy and it seems to be holding pretty good. The biggest PITA is removing and reinstalling the head unit.