People:

Have '88 420 SEL that was running like a top, with 173K on the meter.

Over the past 2 days, have developed 2 unrelated problems. Before I go crazy with unnecessary labor costs, and troubleshooting in the dark, perhaps someone can assist me:

1. A/C blower fan: I had last complained that my fan was blowing, but that it would only blow in the defrost (not middle) vents. Steve correctly advised it was a vacuum problem. I found an unconnected hose, and - shazaam - it blew correctly. The problem now is: the speed of the fan, and that it sometimes will not go on. I.E., it blows somewhat slow - and gets slower while making some light hum as the drive wears on. Then, when I start up again, it may not go on at all for awhile. Could it be an overheating fuse? Anyone have any advice? And if the motor is binding, how can I get to it for lubrication and/or cleaning? I'd like to try something without having to replace the whole thing.

2. My engine is running rough in low rpms. Smooths out fine above about 1800 rpm, but below, runs rough - and sounds more gutteral. I'm thinking it might be a fouled plug ror wire cap, or perhaps a dirty injector or fuel filter, 'cause it seems to have happened almost overnight. Revving the engine doesn't clear it. Any thoughts? Also, seems to have lost some get up and go in the lower ranges. As a hint, perhaps, I can say that my driving patterns have changed lately. Sometimes I go for 4-5 days without running the car at all.

From what I've read it sounds like your blower motor brushes are worn and/or making poor contact. Someone on ebay is selling a set of brushes at an opening price of $26. I don't know where else to get brushes. A new motor is a little over $100 from FastLane.

Check the axial play of the blower motor when you have it out. As the bearings wear, you'll hear the fan cage scrape against the motor housing. And then it really gets fun.

Sixto
91 300SE
87 300SDL
81 300SD

Remove the passengers upper kick panel , just some phillips screws, then look underneath and remove the phillips for the blower cover, you will see a resistor pack let it hang, unplug blower and remove screws for blower housing and you can check it then. You dont have to buy squirrel cage and all they do sell just the blower. Blowers go out and easier and less headache replacing the motor. As for you idle situation it could be a vacuum leak, ignition problem . It really doesnt sound like a fuel problem overnight like that but it could be. That is just diagnosing.

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euro 287
Mercedes Technician 7 Years (retired to Hyundai)
2000 Dodge Durango
98 Mazda truck