Mercedes A/C Problem

engines
intermittent
airconditioning

#1

My 2002 E320 has an intermittent A/C problem that relates to engine RPM/torque requirements. At idle or when cruising under low torque conditions, the A/C works fine. However when accelerating or going up hills, the blower fan stops working.


#2

Are you sure the fan stops working? Could it be that the vents close?


#3

It’s more likely that the vents are changing position, and the recirc door may be closing too. This would indicate a vacuum leak somewhere in the engine or the HVAC system, or a faulty check valve between the engine and the HVAC, in the vacuum line.

-Matt


#4

Yes you are right, the vents change their position as well. The Blower’s RPM’s may drop because of the vent closure. Still don’t know why! Thanks


#5

Hey Thanks Matt, I will look in to it.


#6

Something to keep in mind is that on most cars, the A/C compressor will disengage while there is a high power demand on the engine (accelerating, going uphill). I suppose that the whole system could turn off to avoid blowing hot air on the passengers, but your posting seems to indicate that this is a recent problem. As others have suggested, the first place to look is for a vacuum leak that is causing various doors to shut.


#7

Try these guys, there are a few folks here who really know these systems: