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?

Power steering fluid low or the filter plugged??

This is to be expected on a 118 year old car.

Could be the bearing in the AIR pump.

:confused: :)

Error
 

I know none of you have made a typing error befor. Thanks for the help anyway.

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.

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

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.

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

I hope I am not generalizing too much, but when there is air pump noise on start up, then the air pump bearings are suspect. If the bearing noise is continuous then the pulley bearing is suspect. I just replaced my smog pump with a $225 rebuild and a new check valve ($15), the one closet to the engine. The other valve, sometimes called a diverter valve has a vacuum line coming off it as is closest to the pump. Online sellers of rebuilts often require replacement of these two valves in order for their warranty to be effective. My check valve was choked with soot on the engine side and relatively clean on the pump side. The diverter valve seemed OK, plus it was $50 so I reused it. The check valve is a simple one way rubber flapper. Looking at my new check valve from the engine side, there is a coil spring there that I'm guessing is a heat related shut off. I'm keeping my fingers crossed with the rebuild. The rebuilder used the less expensive chinese bearing that has been talked about. There are many threads on this pulley bearing and it a great DIY project.

glenmore
1991 300CE
2000 C280
1990 LS400

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.