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Differing air temperatures between the vents

MaKSiNG

Well-known member
Joined
3 Jul 2005
Messages
124
Hi all,

With the soaring temps recently this might be an apt question.

My car is a non-AC car so the air coming out of the vents is far from cool anyway. But I am convinced the air coming out of the centre 2 dash vents and possibly the passenger side vents is distinctly warmer than every other vent.

Is this possible?

Additionally I find the glovebox gets very hot. You certainly wouldn't want to transport a drink in there unless it was a cup of coffee ☕️

Thanks!
 
Not noticed that with the air temp , ill check it out , could certainly do with a good drinks holder that wont spill and wont ruin the dash etc
 
MaKSiNG said:
Are you also non-AC?
Do you not have a really hot glovebox?

Coolish glove box ... no AC
 
I think I read something about the HVAC system before. Isn't it really complex with lots of little relays and such?
Maybe one of the relays is stuck. Is that what you mean?

deMort said:
Im not sure if this is something you want to fix yourself but if so heres a link to some info ..

https://drive.google.com/file/d/1iMW3gU7UBBITZRwMpdyIr5zXxNpj0qce/view?usp=sharing

It does sound off hand like a heater motor is not operateing correctly .. i would start with a tester for any fault codes then move onto drive links to see whats working .
 
The HVAC systems on these are a nightmare.

It sounds like a servo of yours is jammed if some are cool yet some are hot, the hot air from the engine is getting around and let in to the car through the jammed vent, if you undo the plastic scuttle cover which is in front of the wiper when the bonnet is up, play with the positions and see if you can see the servos move and change position..

Tore Bergvil came to the rescue of mine, my HVAC unit died along with a thermister? in one of the vents.
 
Just completed a 3 hour motorway drive and boy is it hot in my car. Especially with 30 degree temperatures outside.

Basically the whole bulkhead, the metal part beneath all the wiring under the dash, gets really hot to touch. You really feel the radiating heat on your legs and I presume it heats all of the dash from the back, hence the hot glovebox.

It really must be a stuck servo or vent or some such. The exhaust heat must just be heating up that area constantly.
Annoyingly the recirculating button on my CCU has now also broken and is stuck on permanently, maybe it's related too.

What were they thinking with this over engineered HVAC unit :pc:
 
Have you checked the heater hose that runs from the sill to the heater on that side of the car. Mine had a small split in it and allowed the hot air from the heat exchanger to be fed into the car. On mine the hot air even made the radio to hot to touch. There are also flaps either side of the car, they usually rattle when you shut the door, that open and close depending on the heater position. These can stick I believe, I think there is a thread on here about refurbishing them.
 
treefrog99 said:
Have you checked the heater hose that runs from the sill to the heater on that side of the car. Mine had a small split in it and allowed the hot air from the heat exchanger to be fed into the car. On mine the hot air even made the radio to hot to touch. There are also flaps either side of the car, they usually rattle when you shut the door, that open and close depending on the heater position. These can stick I believe, I think there is a thread on here about refurbishing them.

This sounds like it could be my exact problem!!! Thank you!!!
So peel the carpet back in the footwell and I should see the hose on the outer wall near the sill?
And what about the flaps? Are these attached to the end of the hose? They rattle? Never noticed this.
I'll take a look see what is under the carpet in the footwell.
Don't suppose you have a link to the refurbishing of these 🙄

Many thanks!
 
Yes the pipe runs behind the carpet.
The flapper valve is quote"The differential flapper valve is installed into the junction of the ducting system between the heat exchanger outlet and the pipes that lead off the left and right mixing chambers" Adrian Streather.
The article on how to refurbish/check I cannot remeber where I read it either on here or in the PCGB mag.
This may help and you may be able to contact the author.

on 911.co.uk The Redbaron thread page 31 about half way down.

Trev
 
treefrog99 said:
Yes the pipe runs behind the carpet.
The flapper valve is quote"The differential flapper valve is installed into the junction of the ducting system between the heat exchanger outlet and the pipes that lead off the left and right mixing chambers" Adrian Streather.
The article on how to refurbish/check I cannot remeber where I read it either on here or in the PCGB mag.
This may help and you may be able to contact the author.

on 911.co.uk The Redbaron thread page 31 about half way down.

Trev

Cheers Trev. You are a legend.
Nice easy job then ... NOT!!!
 
Interesting enough, I have had a clicking noise coming from the footwell for sometime and I now convinced this could be this heating flap opening and closing sporadically.

Must investigate further.
 

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