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#1
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300 E whine
When I first start my 1889 300E there is a moderatly loud whine that come from the front lower part of the motor. As the motor warms up it goes away. The noise is only noticable when the engine id cold. Any Ideas?
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#2
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Power steering fluid low or the filter plugged??
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Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician |
#3
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This is to be expected on a 118 year old car.
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#4
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Could be the bearing in the AIR pump.
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2012 E350 2006 Callaway SC560 |
#5
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1996 E320 since 1/16/08, 171K miles as of Feb 2011 --------------------------------------------------------- 1989 300CE - R.I.P. Dec 29 2007 Other MBs (sold): 1992 300E-24 - 1979 350SLC - 1984 230E - 1990 300CE |
#6
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Error
I know none of you have made a typing error befor. Thanks for the help anyway.
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#7
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I'm inclined to favor the air pump bearings beginning their "swan song" so to speak.
Since the intake mixture is fuel rich when the engine is cold, the air pump is designed to enrich the exhaust with air prior to going to the cat upon startup. An unnecessary piece of equipment on US-spec vehicles, european smog inspections require tailpipe sniffing within 60 seconds of vehicle startup. The pump does its job in the fist few minutes and then shuts off...which may be why you don't hear the "whine" after that.
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2009 ML350 (106K) - Family vehicle 2001 CLK430 Cabriolet (80K) - Wife's car 2005 BMW 645CI (138K) - My daily driver 2016 Mustang (32K) - Daughter's car |
#8
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The AIR pump is pretty easy to check- just find the wire going to it and trace it back to the connector (probably next to the coolant reservoir) and unplug the wire. If the sound goes away, voila. It has a magnetic clutch just like an AC compressor, so, no wire = no engagement of the pump.
You can leave this wire unhooked, no problem at all, as stated above. However, I think it might be a good idea to also disable the check valve on the outlet side of the pump. This valve opens via a vacuum line when the pump runs, allowing the air to enter the exhaust manifold. If the pump were disabled and the check valve opened during initial wartmup, would the hot exhaust then be able to travel back into the pump and fry it? Just unhook and plug the vacuum hose to be sure. DG |
#9
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Thanks for your help. I'm pretty sure it's the air pump also. I think I'll disconnect it for now because it's $650 to replace.
Last edited by groller45; 05-04-2007 at 08:53 PM. |
#10
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Diagnosing this kind of noises is relatively easy with a car stethoscope. Even very cheap ones from car parts stores work rather well. If you put the tip on the suspected part you can clearly hear if it is making excessive noise. The bearing of the serpentine belt guide pulleys sometimes fail and make a similar noise.
Rob |
#11
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Quote:
glenmore 1991 300CE 2000 C280 1990 LS400 |
#12
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engine noise
My car die'ed om me the other day. I was lucky I wasn't on the freeway. When My service person looked at my car to get it restarted I asked him about the air pump noise. As it turned out I don't have a air pump on my car. (Maybe because it's 118 years old). We did find out the battery went bad and that is why my car die'ed. He put a new voltage reulator in the alternator (just a precaution) and replaced the battery. He said the alternator was having to put out so much electricity to keep the batery up that the alternator was making the noise. Hopfully problem solved.
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