W208 55 AMG poor airflow

[Bennal]

I've just upgraded from my CLK320 to a 55 AMG and am having a problem with the blowers on the new car. There is only a tiny amount of air coming out of the vents even with the fan set on maximum. To put it in perspective, my 320 (no climate control but has air con) puts out a huge amount more air on fan setting 1 than the 55 does on the highest fan setting (full climate control).

Having read a some useful posts on blower issues I've had the blower motor out expecting it to be clogged full of rubbish but it looked fine. The fan speed adjustment seems to work as the motor output changes in line with the adjustment. I left the motor disconnected and tested the buttons for changing the fan output type and I could hear the typical clunk inside the dash indicating the outlet was being changed. The pollen filter was changed last week as part of a service.

I've also checked the white vacuum cable in the engine bay and that looks fine. There is a sort of buzzing/hissing coming from the back of the engine bay where the white cable goes into the black one, but I'm not sure if that is a normal thing or not, and it does sound more electrical than air related to me.

Can anyone provide me with an idea of what to check next?

 

[andy27168]

If the motor is changing speed as it should then I would be looking at the removing the pollen filter first, and see if that makes any difference, the air flow in my car was severely restricted, changed the Pollen filter and it was perfect again, the pollen filter gets missed in servicing as there is no requirement to change it in the service schedule.

 

[flango]

There are two types of motor fitted to this car as standard as I have just found out. A Hella Unit and a Valeo unit. I have just replaced a Hella with a Valeo and the output from the Valeo is not as much as the Hella its fine and it does the job but on max speed its no where near the airflow of the original Hella unit. So maybe this is what you are also experiencing and comparing a Hella to a Valeo?