[ollyy]

Hi,
My 2003 W209 CLK 320 heater blows cold air into the cabin when I go round corners. Any ideas please? I take a route to work with lots of bends and as it's starting to get chilly in the mornings I'd really like to put a stop to it.

Thanks Oliver

 

[rudeney]

It could be a problem with the dampers or their servos in the ducts. Try the ACC test/reset:

With the engine running, simultaneously press and hold the RECIRC and FRONT DEFOG buttons until their indicator lights begin to blink. They should blink 20-30 seconds then stop. If they don't stop, then you have a damper control problem and will nee proper equipment (SDS) to diagnose.

 

[keyhole]

Hi,
My 2003 W209 CLK 320 heater blows cold air into the cabin when I go round corners.

With the greatest of respect, I find this statement almost unbelievable....

The climate control system has no idea when you are turning corners, and the g forces generated when turning could not possible affect the a/c dampers. The car's accelerometers are used for ABS control.

There must be another cause of this unwanted cold air.

 

[cwilson21]

With the greatest of respect, I find this statement almost unbelievable....

The climate control system has no idea when you are turning corners, and the g forces generated when turning could not possible affect the a/c dampers. The car's accelerometers are used for ABS control.

There must be another cause of this unwanted cold air.

Could be a vacuum leak... Not positive about the Benz, but most damper systems use engine vacuum. But you should also notice the same thing if braking hard in a straight line (brake boosters work off of vacuum)....

 

[keyhole]

Not positive about the Benz, but most damper systems use engine vacuum.

Nice idea... but W209 models have an all-electric a/c system.

 

[rudeney]

It's possible there is a short in a servo that only occurs with the G-forces in corners. It could also be a defective duo valve where the coolant is routed into the heater core. For a bad part, it might not take much G-force to trigger it.

 

[ollyy]

With the greatest of respect, I find this statement almost unbelievable....

There must be another cause of this unwanted cold air.

I am describing the symptom accurately, I have no idea of the cause.

I pressed recirculate and demist at the same time, they flashed alternately and went through a blower test cycle. We ended up with the demister light on.

I've asked the question on another forum and "duo" valve was mentioned there too...hmmm

Thanks Oliver

 

[cwilson21]

Curious.... Does it happen when turning in only one direction or both left and right?

 

[ollyy]

Fairly sure it's in both directions, I'll try and do some more controlled examination, under acceleration, deceleration, with or without the air-con on (have tried the latter actually and it happens in both scenarios).
Does anyone have a good detailed breakdown of how the system works, what the components are etc etc please?

 

[keyhole]

I've asked the question on another forum and "duo" valve was mentioned there too...hmmm

I think that you can forget the duovalve possiblity... they are used on W202 C-class and W208 CLK, but not on your W209.

 

[cwilson21]

OK... I'll be the first to ask the obvious... Is your coolant level topped off?? I had a car once that would had a leak and get low, but because of the leak the overflow canister (where the sensor was) stayed full. End result, no heat....

 

[keyhole]

Hi,
My 2003 W209 CLK 320 heater blows cold air into the cabin when I go round corners.

I think that to bring some credibility to this question, we should get some diagnostic measurements of temperature from the OP. The statement of 'cold air' needs clarification. How cold?

Maybe the OP could take some temperature measurements with the car moving in a straight line, then repeat with the car turning.

The CLK does not have a heater as such. The heat exchanger is one component of the climate control system, and the conditioned air exits from a number of vents. The diagram below shows the operation, where ALL the air is chilled/de-humidified prior to subsequent heating as required. The drawing is for a W220 system, but it is similar to the W209 arrangement. Click to enlarge.