Hot air on a hot day (from cold air vent!)

[13022]

Has anyone else had problems with hot air from the cold air vents on a hot day (Merc 190E/1997cc/1990)(with heater turned off!) ... and its not just that its a hot day - the output air is warmer than the ambient temprature!

Tried replacing the heater control valve, and verified that it is closing under the vacuum pressure but problem persists.

If anyone can get me cool air on hot day in Dublin's h*ll
ish traffic, I'll be very happy!

 

[Anonymous]

have just joined forum hence delay in responding.  Can't help but have similar problem in a W124, air red hot after engine warm up have to manually slam a/c controls to freezing to get rid of it.

did you solve it? any clues?

Keith

 

[dave elcome]

I sometimes get the same problem on my W124, but mine hasn't got A/C.

 

[13022]

Didn't solve it, though its not a problem until the Spring! My car doesn't have a/c. There's some kind of foam pad in the engine compartment that I suspect is a heat shield protecting the ventilation system from the heat of the engine. I have a theory that because this is ripped to shreds on my car, that maybe this is the source of the problem, and its just the heat of the engine which warms the intake air slightly and is noticed only in the summer... but I'd accept a better explanation!!

 

[Anonymous]

Andy replied to my other post, saying that he suspects the hot water duo valve is sticking.  could it be the same for yours?, this is not to do with a/c just the heating circuit.

 

[Andy]

Hi Mark

I did  reply to your posting. Only I hit the reset button late last night so lost all the typing. It was too late to type all again. And my bed was calling me.

With regards to your vehicle. The heating system is completly different to the 124. I suspect that a cables behind the heater knobs is not shutting or opening the heater flaps correctly. You need to drop the heater pod for furhter investigation.

Sorry I can't be more specif.

Regards

Andy @ www.mercedesservicing.com