Hi,
My 98 s420 whines at cold start. It sounds like a vacuum cleaner and stops after about 45 seconds. Also I am unable to reset my trip odometer. The owners manual says to push button 1 twice when key not in ignition or push it once with key in position 1 or 2. Neither works. Any ideas ???? Thanks

smk_texas
98 s420 - 50 k

The "vacuum cleaner" sound you hear sometimes at cold start up is the engine air pump. On your motor, the M119, its located on the passenger side of the engine just above the alternator. Its electrically driven by an internal motor.

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KenP

1996 S500 W140 Coupe

You're kidding right?
" COLD starts " in Texas?
Come & visit me, you'll see what cold starts are like........pussy!

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2007 C 230 Sport.

Yup, it's the air pump. Mine was very noisy, so I took it out last weekend to see if anything could be done. I could not get the fan pulled apart because the 13mm nut on the shaft would not let loose. I believe a bearing is worn and would like to replace it, but gave up and put it back together. Magically, it's much quieter now. It's on my '98 c230.

Thanks Guys. I 'll take a look at it this weekend.

smk_texas
98 S420 50K