’82 240D squallin’ and squealin’, - PeachParts Mercedes-Benz Forum

cgryphon · #1 03-19-2005, 10:44 PM

Thought I had this fixed (twice). When I bought the car from the PO, it had some low RPM squalling that would build until the revs got up, and then it would disappear. My indy replaced all the belts and the crank pulley. We were good to go for about a week, and then it started up again.

My driveway test revealed that I had to put a load on the electrical system to get it to squeal. Headlights and heater fan added at idle, step on the accelerator, and here’s the squall/squeal. My indy, being the guy that he is, decided to give it a new belt and alternator and an alt. bracket he said he had “out in the yard.” $175 for the alt. (Bosch) $12 for the belt (Conti), plus tax, brought it up to $200. He charged me NO LABOR! Said he should have caught it on the first go round.

One week later the squall/squeal is back. Noticed it driving home from work last night. I have to turn on at least the lights to get it to yell. Light and heater fan will get it going in the driveway. It gets louder/faster as I accelerate away from a stop, then cuts off once the RPM’s get high enough. It will follow all the way up through the gears and may keep going while cruising, but it’s hard to hear for this old guy in this old car. What’s up with that? I checked the belt, and if anything I think it is loose.

Please tell me it’s not the water pump. Operating temp. is normal, at about 85 to 90 C. 20 miles work to home, 50/50 hwy/city. Car is running great otherwise. 25 MPG mixed, good shifting, and powerful 240D acceleration

No issue in the daytime, unless I turn on the lights.

I searched and learned some, but I wanted to ask the question specifically. Thanks in advance for your comments and ideas.

Clay

83-240D · #2 03-19-2005, 11:03 PM

first thing i think is water pump. have you had someone step on the accelerator while you listen at the front with the hood up?

Jimmy Joe · #3 03-20-2005, 05:38 AM

No drips at all from the weep holes on the water pump?
Even still, if there are any doubts, it is not a hard job.
Got mine for $70 from the dealer, swapped it out in an afternoon. The fan was the toughest-had to grind down o wrench to get in there....

cgryphon · #4 03-20-2005, 09:49 AM

83-240D: I have only listened from the drivers seat. I can only get it to squeal if I turn on the lights, heater fan, etc. No noise at idle, just when it's reved up. It seems so loud with the hood open, door open, sitting in the driver’s seat, that it would be hard to localize. Good idea, I’m going out to try it today.

JJ: I checked the weep hole at the top and it is dry. The exposed part of the pump, where it bolts up is rusted, but looks like it would be, as it is just bare metal. Car has no rust as a general statement.

Other maybe clues are:
1. The radiator is never perfectly full. I do not have a reservoir, just fill to the little line inside the neck. It never stays right up to the line. Gets about 3/8” below the line, but never gets any lower.
2. When I got the car it did not have a fan shroud. It does now.
3. If I grab the big, black cylinder part of the shaft behind the fan, but in front of the pump, it does not seem like it wiggles, but I can see the tension on the belt change. At this point I’m shoving it hard enough to move the whole front end of the car. The belt tension is changing for sure.

Thanks,

Clay

barry123400 · #5 03-20-2005, 03:09 PM

New belts will stretch and need adjustment occasionally. General statement in my experience. If you can turn alternator fan with your finger the belt is too loose. (engine off needless to say) Another contributing factor is to check the pulleys for rust as car may have sat around too long before your purchase. Rust on grooves in pulleys will make the belt wear and loosen fast. Grooves that belt rides in should be almost shiney. If not you have to clean them up. Basically you have been describing a loose belt I believe.

cgryphon · #6 03-20-2005, 03:24 PM

Having a look today in the light. Still squealing, but only if I get the lights and fan going. Belt seems loose. Yes, I can turn the alt. fan with my fingers, easily in fact.

Additional comments welcome and thanks for those I have so far. Pulleys seem clean overall.

Clay

Jimmy Joe · #7 03-20-2005, 04:22 PM

Quote:

Originally Posted by cgryphon

Yes, I can turn the alt. fan with my fingers, easily in fact.

Clay

What? I sure can't. That doesn't sound right...

leathermang · #8 03-20-2005, 04:34 PM

Something is wrong...

You should not be able to move the fan that easily...
Check to see if they sold you the wrong belt. If the angle the belt is made is not the same as the angle of the pulley then you have real lack of friction problems ( translates to noise ). If the angle is not correct it is almost impossible to get it tight enough to avoid noise....Stranger things have happened ( TO ME ) than a belt being misslabled at the factory (for example)... it will REALLY cause some head scratching...

Another possibility is a bearing going out in the alternator.. I can not think of anything which adding an electrical load would point to the water pump.. unless you are running one of those rare electric water pumps on your car...

barry123400 · #9 03-20-2005, 08:15 PM

This second guessing is pretty dangerous but how much do you trust your mechanic and why did he change your crank pulley? Am not particularly wild about the alternator being changed out either unless he gave you a reasonable reason. At this stage I would just retension belt and see what happens. There is a little toothed bolt on the alternator mount to help you adjust it. You first have to loosen up the nut on that bolt first. See what happens after that. Retighten it after the adjustment of course. It is certain that if you can move the alternator fan pulley with your finger that the belt is going to squeel. That belt has to have enough tension so that the pulley cannot be turned by finger pressure. Left long enough and you will not have enough current in your battery to even start the car. Leathermag makes some interesting observations as well. Stay away from that mechanic until you figure out what is going on at least. Ask a friend with a little more knowledge perhaps than yourself to participate if required. There is a possibility that i'am wrong of course because as i mentioned all above is only second guessing.

cgryphon · #10 03-20-2005, 09:53 PM

Well, seems certain that we have a tension problem. Between bouts of landscaping today

I looked it over a couple of times. Easy to turn the alt. fan or the big fan by hand. I took a close look at all the pulleys and they all seem fine. Interesting that the alt. pulley is the only one that is “stepped” ???? I’ll try to explain: All of the pulleys are smooth feeling down into the V. The alt. pulley almost feels like it is made of two concentric pieces. The larger of the two is maybe 1/16 inch bigger, and then you can feel a slight groove, then the smooth pulley the rest of the way. The groove runs perfectly all the way around. It really looks/feels like it was made that way. This is a Bosch alt. Do they come with the fan and pulley attached? Is this the way it is supposed to be?

My indy is Erol’s, in Nashville. He also works on my C220 and his place is always packed. Always fun to see the 240D up on the lift next to an S600. Obviously some of his customers have the money to take their cars to the dealer. People sell cars here in Nashville and say, “Erol maintained” in the classified ad. I found him through this forum (thanks Dave) and he’s done a lot of work on this car so far.

I bought it for $1000 just after Christmas. He’s done all sorts of stuff, from replacing all the side glass with excellent used (it looked like it had ice scraped off it with a shovel) at $50 per window, to getting the original Becker Europa working (N/C) and getting the power antenna working (it was lying in the trunk) again N/C. Suffice it to say I am pleased and I trust him. I think they just overlooked getting this right. A little weird that it did not show up for a week, but maybe the new belt was just making it work for a while. FWIW, the size is Conti AVX13 x 1000 La.

I be taking it over there first thing tomorrow so I’ll post the results

Thanks for all the advice and suggestions,

Clay

Ps. Second-guessing is a good thing; it often helps uncover the truth.

psfred · #11 03-20-2005, 11:30 PM

The squeal is a loose belt, but if it happens again very quickly after re-tensioning, I'd start looking for the cause of excessive belt wear. This can be bad pulleys, a missing crank spacer (this will cause serious oil leakage, though -- don't laugh, we left it out of my brother's car since it didn't have one when we took it apart...), or a bad water pump. If the water pump shaft is moving out of the bearing, the belt will be get pushed sideways -- this wears it pretty fast.

I've also had an alternator bind up internally, causing the belt to wear excessively fast, but you've had the alternator replaced already.

Peter

barry123400 · #12 03-21-2005, 12:08 PM

Good to hear your mechanic has generally been satisfactory. If I understand your description there is a pronounced ridge on pully face where the v belt contacts on one side only. That sounds a little strange but may be normal. In fact if step about at same height of the top of the otherside of the pulley it is an engineered feature to load the belt equally on each side. If problem persists see if you can compare it to the pulley on your old alternator if possible. You may have to install your old pulley on your new used alternator if there is a noticeable difference. You quoted I believe he also changed the alternator mount. That may or may not indicate several things as well but the question in my mind is why? Different mount type alternator enters my mind for starters. On the otherhand original bracket design may be prone to bending/wear perhaps but cannot really see that. Could have just been broken somehow as well though. Might have shifted pulley alignment out or in a little by this change if a different alternator or pulley type was used. All pulleys have to run on same plane. But pretty sure he will pay a lot more attention when you go back in this time anyways. Again hopefully just a belt that needs retensioning rather than a tempest in a teapot. A squeeling belt is about the only way a 240d recieves attention while accelerating I would think. So must try it myself as own two of them.

In the old days while traveling and my belt loosened up a little I would just get a bar of soap. Rubbing the contact portions of the belt would stop the squeel and increase belt traction enough that my generator/alternator did not stop charging properly. This was useful during a sunday outing if no place or tools on hand to tighten belt and it was a long way home at night.

cgryphon · #13 03-24-2005, 10:50 AM

Just closing this story out.

Finally had a chance to go back over to my indy. I showed them that the alt. fan could be turned by hand, and, just as many of you said, “that can’t be right”. Despite being very busy with Spring Break travelers, they pulled it right in and fixed it. They even put on a new belt “in case the belt got damaged running loose”. Tightened everything up and sent me on my way, no charge, no shop ticket written up, nothing but a smile.

I did question them on the water pump and they said it was fine. I’ll take them a couple of cakes today (I’m the Ops and R&D director for a wholesale decorated cake bakery here in Nashville. We make about 5,000 cakes a day) to keep them going. A well fed tech. is a happy tech.

Have a great Easter and thanks for the help.

Clay

leathermang · #14 03-24-2005, 12:58 PM

"Thought I had this fixed (twice)....... My indy replaced all the belts and the crank pulley. We were good to go for about a week, and then it started up again. "--clay

Wait a week to take him the cakes to see if this is not DejaVU all over again... LOL

cgryphon · #15 03-24-2005, 05:35 PM

Made me laugh! I'm going to take my chances and go on over today. If it's not the belts it will probably be something else by next week!

Thanks for the HA HA.

Clay