getting heat out of vents even heat is off

[droppedbenz]

hey guys does anybody out there had this problem in the past in my 1995 c280 i seem to be getting heat coming out of my vents when my climate control unit is turned off it blows even more when im in the highway can anyone tell me what can be causing this? wanna get this issue fixed before the summer gets here i roast in my car lol

[ja2k]

I am having this issue as well. Can anyone please provide insight on this matter. I thank you for your help in advance.

[martattack]

I know this original thread is a year old, but I have some insight for you ja2k...
Most likely is that the duo-valve is stuck in the open position. The duo-valve is what regulates the hot water to the heater core, so if it gets stuck open, your car could very well be heating the heater core and running air through it. A possible quick fix is to give the duo-valve a good smack with a blunt object to see if you can get it to release from it's gummed up, stuck open state. The duo-valve is located under the electronics area under the hood on the right side by the firewall. It looks like two D-sized batteries on end. Search for duovalve and you will find many threads.

Martin

[mazdalowandslow]

Ack i would hesitate to hit it, rather disconnect it and clean it out properly. I had the same issue with mine, clean it out and have never had an issue since. I would also do a coolant flush at the same time, that will remove possible debris from the system.

[mazdalowandslow]

Here is the DIY.
http://www.benzworld.org/forums/w210-e-class/1350793-duovalve-removal-cleaning.html

[ja2k]

Thank you all for your alacrity. It was in fact the duo valve.