HVAC blower only putting out air at dash vents - servo bad? also oil leak front pan
 

I am in the market for a Mercedes and have several different ones that I am considering. One is a 1983 300SD that has a problem with the HVAC. The blower only puts out air at the dash, none on the floor or defrost. The owner said that his mechanic told him it was a bad "servo"- also said it was not an
expensive part, but dash panel had to be removed. Exactly how much of the panel has to be removed and about how long does it take? Also- is the malfunctioning part actually the "servo"? If not, any suggestions? Must be a common problem. I was considering another 300SD a while back with the same woe.

The other is a 1985 500SEL that I am considering. It has 152k. There are no drips from the oil pan, but the gasket looks like it has been "weeping" a bit, as it has a darker look around the gasket area. My main concern is that there appears to be some seepage just above the actual oil pan, toward the front of the pan. Does anyone know where the oil may be leaking from? Where does oil typically leak at on these cars? Also, are these cars supposed to have a dangling hose (appears to be a vent hose) down by the passenger side of the rear axle?

Thanks in advance.

Cam and head gasket replacement
 

I just had an oil leak problem on an 88 300 SEL.
It looked like it was dripping from the pan to me.
Turned out it was coming from the cam gasket and head gasket. With all of the other parts that has to be replaced when doing this it was a $1660 job. 13.5 hours labor.

Some more investigation is needed, preferrably by someon who is experienced with M-B HVAC systems.

The 'failure' mode, when there is no vacuum on acutator modules, is air will come out of the Defrost vents, and 'leak' from the side vents. So, a 'failed servo' should give you Defrost.

The floor vents are only used for Heating. They require a signal to the vacuum switch from the ACC panel, a good vacuum actuator, and good linkage to open the vent.

The center vents are only used in Cooling mode, not Heating, so they're harder to test in cold weather.

There are vacuum switches that actuate vacuum modules under the dash.

The vacuum switches are accessible by removing the right side of the console, and the actuators are behind the radio and switch panel, which must come off for access.

Good diagnosis first, with vacuum gage and in the right sequence, will tell which actuator(s) might be leaking, before removing panels and other equipment.

Best Regards
Jim