Vacuum pump on a M103?
 

The pump looking thing above the alternator seems to have a pulley that's not turning freely. It started making a squealing noise. Now it's louder and I noticed the pulley isn't turning as fast as the other items connected to the serp belt.

Also, my aux fan doesn't seem to be coming on at lower temps resulting in temp rising to 100 at a long light. as soon as I stert moving the temp drops back to 85.

Could the two be related? What is this pump thingy and can it be repaired or does it need to be replaced? BTW, it's a '90 300SE.

Mr. Bill
Thats the air pump, it is a piece of anti-pollution equipment. It only runs for a few minutes upon cold start-up. They are generally considered a replacement only item. The clutch assembly is available seperately. If it's noisy with the engine running after warm-up, it's probably just the clutch assembly. They get alot of money for just the clutch, be sure to price out the whole assembly vs just the clutch, it may be better to replace the whole thing. You may get some comments about repairs being done, by all means feel free to try a repair.
The aux fans run based on either A/C freon pressure (low speed fan) or engine temp (high speed fan). If the A/C is off (incl defroster), then I doubt the fans should be running at 90 degrees, the engine temp has to be I believe at about 100 degrees before the high speed fan comes on. Sounds more like the thermostat or partially plugged radiator is to blame. You can have the area between the A/C condensor and radiator checked for blockage also, it can really fill up with road debris between there.
Gilly

Bill:

Do you have an owners manual? Look on page 99. It's the air pump.

Thanks guys,

It looks like the pump is an expensive item to replace.

Parts Shop - with pulley - $535.00
Lots of money for something that functions for about the first 2 mins. that your car is running. Thank you Ralph Nader.

Mike,

No kidding reference the cost of this stupid thing. I think I'm doing to look for a used one or a clutch kit. This one lasted 265K+, so a used one even with a 100K+ on it should do the trick. BTW, how's your 300SE running?