terrible noise - PeachParts Mercedes-Benz Forum

kchemers · #1 12-16-2002, 09:41 AM

I have a 1976 240D I have been getting a terrible shreiking noise that comes and goes when under acceleration. It sounds like the belts are slipping. I changed the belts and the noise is back. It doesnt matter if the car is hot or cold. The noise comes whenever! Any ideas???
Thanks, kchemers

wheelguru · #2 12-16-2002, 11:39 AM

My 300d did it to-terrible noise, I thought it was the fan coupler. it was not the belts, or the fan, it was the waterpump!!, which failed before I figured out what it was, and cooked the rings. Talk about your oil consumption! I am not sure how you would check it, but seeing as how a rebuilt pump is about $25 at the dealer I would think about just replacing it on general principle.

wheelguru · #3 12-16-2002, 01:02 PM

it wasn't locked, that is why I am not sure how you would check it. The manual shows that the impeller and drive shaft are just pressed together - the outer half is half is heated and pressed onto the cool shaft. They should cinch down tight as the outer part contracts. What must have happened on mine is that the shaft started to slip and not turn the impeller. It still worked enough that I took the thermostat out for a couple of days and ran it that way without more problems until I could get the new pump in. Of course the rings were already shot from pegging the temp gauge - I started buying oil in 5 gallon buckets at Fleet Farm after that.

Great Boob · #4 12-16-2002, 03:17 PM

One more possibility, Maybe I'm paranoid now, and I hope its not this, but when my 79 TD balancer sheared its retaining pins it made an awful scream, I was on the interstate at speed. It stopped and would not repeat the noise. About a week later the balancer came completly loose.

Keep in mind it only made the noise once, so if yours repeats squealing, like when you start out, it's probably belts..

#5 12-16-2002, 05:42 PM

I have posted this before...
Belts you buy from McParts places are not the same thing as what you get when you buy the "real deal" from places like FastLane. The McParts belts are the correct length, but not the correct width. they will fit but they will slip like crazy a few days after you install them. Spend the extra $5.00 or so per set for true German belts, once you install them you are finished.

jbaj007 · #6 12-16-2002, 11:56 PM

I apparently failed to adequately torque the alternator pulley nut and the rattle/"shriek" was pretty loud as the Woodruff key disintegrated.

andy · #7 12-17-2002, 03:17 PM

My car makes that slipping belt sound sometimes and only with the heater on. If I turn the heater off the noise stops. Any ideas? andy

#8 12-17-2002, 08:52 PM

I forget what brand I got from Fastlane but do know they have "Made in Germany" on them. The difference I saw was they fill the pully all the way up to the point that the top edge of the belt gets little fuzzies on it when you first run them. The only belt I had real issues with was the A/C belt on the 240. Every belt I bought local would work fine for a few days then need to be cinched up. They both failed in about a week of use. The FastLane belt has worked from day one and I never had to tighten it up after a few days. Sold me.

kchemers · #9 01-21-2003, 03:23 PM

Bought a new alternator adjusting bolt, and everything is just great now. No more noise and the alternator light stays off.
Thanks for all the advice, I love this site!