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  #1  
Old 12-28-2009, 04:59 PM
BodhiBenz1987's Avatar
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Anatomy of a squeal (240D) w/ sound file

Well, I was marveling this afternoon about how incredibly my 240D started, ran and drove in the 30ish-degree weather ... and sure enough, it started to make this awful squealing sound under load. Chase never lets me get bored. It made a similar sound a couple months ago one very cold night, and I thought it was the belts. At that time I found the p/s pump pretty much falling off, tightened it up and it fixed the problem. But, now the squeal is back. Or maybe a different one. Here's the low-down: I can't reproduce it when the car isn't in gear. It begins when the car is in first and get louder as the RPMs increase. When I put the clutch in, it stops ... it starts again after shifting into second, same deal, increasing with RPMs. It sounds like it's coming from the front of the engine, but it sound direction can be deceiving.
Here is a video ... there's no image, but you can hear the sounds in the background as I drive up the street in first, shift to second, turn around and do the same on the way back to my driveway. http://www.youtube.com/watch?v=hlNqKfHUYWU
Thoughts? My inclination would be belts, but all are tight but not too tight. Also I'd think it would make the sound when revved out of gear, too, in that event. Could it be a clutch issue? Exhaust? Something else? I know I asked about this the last time it squealed, but I'm treating it as a new issue since tightened the ps belt seemed to fix it last time. Also thought maybe the sound file would help.
Thanks!

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)
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  #2  
Old 12-28-2009, 05:21 PM
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Quote:
Originally Posted by BodhiBenz1987 View Post
Well, I was marveling this afternoon about how incredibly my 240D started, ran and drove in the 30ish-degree weather ... and sure enough, it started to make this awful squealing sound under load. Chase never lets me get bored. It made a similar sound a couple months ago one very cold night, and I thought it was the belts. At that time I found the p/s pump pretty much falling off, tightened it up and it fixed the problem. But, now the squeal is back. Or maybe a different one. Here's the low-down: I can't reproduce it when the car isn't in gear. It begins when the car is in first and get louder as the RPMs increase. When I put the clutch in, it stops ... it starts again after shifting into second, same deal, increasing with RPMs. It sounds like it's coming from the front of the engine, but it sound direction can be deceiving.
Here is a video ... there's no image, but you can hear the sounds in the background as I drive up the street in first, shift to second, turn around and do the same on the way back to my driveway. http://www.youtube.com/watch?v=hlNqKfHUYWU
Thoughts? My inclination would be belts, but all are tight but not too tight. Also I'd think it would make the sound when revved out of gear, too, in that event. Could it be a clutch issue? Exhaust? Something else? I know I asked about this the last time it squealed, but I'm treating it as a new issue since tightened the ps belt seemed to fix it last time. Also thought maybe the sound file would help.
Thanks!
To me it sounds exactly like the squealing alternator belt that I just replaced on my 1983 300SD Auto. It would be mostly apparent when the car was in park or at idle and tend to go away once I was underway.

In my case it felt properly tight, however they were some cheapy auto parts store brand. I replaced all with Conti-tech belts which I suggest if yours are not.
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  #3  
Old 12-28-2009, 05:38 PM
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Quote:
Originally Posted by tr1cky View Post
To me it sounds exactly like the squealing alternator belt that I just replaced on my 1983 300SD Auto. It would be mostly apparent when the car was in park or at idle and tend to go away once I was underway.

In my case it felt properly tight, however they were some cheapy auto parts store brand. I replaced all with Conti-tech belts which I suggest if yours are not.
Mine are OE, replaced about six months ago ... however, I haven't gotten around to replacing the alternator adjustment bolt, which is a little chewed up, so maybe it's just a very slight bit too loose. Still, it seems odd that mine doesn't make the noise at idle or even when revved out of gear.
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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)
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  #4  
Old 12-28-2009, 05:47 PM
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Sounds like a belt to me. Does it do it when the engine is warmed up?

There is one thing you might want to try, when you are idling not in gear. Try turning the steering wheel back and forth. If it squeals, then it could be your power steering pump. If not, then you can possibly rule it out and check the other belt driven accessories.



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  #5  
Old 12-28-2009, 06:31 PM
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Quote:
Originally Posted by DeliveryValve View Post
Sounds like a belt to me. Does it do it when the engine is warmed up?

There is one thing you might want to try, when you are idling not in gear. Try turning the steering wheel back and forth. If it squeals, then it could be your power steering pump. If not, then you can possibly rule it out and check the other belt driven accessories.
The car was pretty warm, although not at full operating temperature. It was in the high 30s today ambient temp. I didn't want to drive it around too much making that awful noise. It's tough to pinpoint the source of the noise when it won't do it with the car sitting still. I'll try tightening things and see if it goes away. I don't think it's the PS pump ... I had to turn the wheel all over the place to maneuver the car out of the garage but it didn't make any noise until going straight down the road.
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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)
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  #6  
Old 12-28-2009, 06:51 PM
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I am leaning towards the clutch or something in the trans. Another simple question, Do you know if your trans has fluid in it?

Also, if you release the clutch to put a slight drag while standing still does it make any hint of the noise?



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  #7  
Old 12-28-2009, 07:15 PM
BodhiBenz1987's Avatar
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Quote:
Originally Posted by DeliveryValve View Post
I am leaning towards the clutch or something in the trans. Another simple question, Do you know if your trans has fluid in it?

Also, if you release the clutch to put a slight drag while standing still does it make any hint of the noise?
I don't hear any noise when I release the clutch slightly with the car standing still. It doesn't make the noise with the clutch released and the car going very slow. I don't have a tach but I would say it starts making noise when the car is under load and about 1,200 rpms.
I have not checked the trans fluid. Good call. I need to do that regardless of whether it's the noise source or not. I haven't even checked it since I bought it ... . I really hope it's not something catastrophic happening ... I've finally made some real progress with the engine and even some of the body.
__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)
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  #8  
Old 12-28-2009, 07:28 PM
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First check oil in trans. then;
1/ While the car is stationary engine running, clutch down, in gear, headlights on, rear window heater on (if it has one), anything else electrical going. Rev the motor up to at least 2,500rpm. If its the belt, it should do it under these conditions. Repeat with car in neutral foot off clutch. You didnt rev the car enough in the audio.

2/With nothing electrical on, in neutral, rev motor, while revving motor any of the sound? Try pressing clutch down while in neutral and revving. Any of the sound?

3/ While driving down the road & the sound there, put car in neutral, does sound go away?
4/ While driving down the road with the noise, put foot on clutch, does noise change pitch or go away?
Please post the answers to these questions & we will have a better idea of the cause.
I am leaning to the thrust bearing or drive shaft bearing or even a stick jammed up under the car, still could be the alt belt though.
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1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
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  #9  
Old 12-28-2009, 08:11 PM
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Quote:
Originally Posted by layback40 View Post
First check oil in trans. then;
1/ While the car is stationary engine running, clutch down, in gear, headlights on, rear window heater on (if it has one), anything else electrical going. Rev the motor up to at least 2,500rpm. If its the belt, it should do it under these conditions. Repeat with car in neutral foot off clutch. You didnt rev the car enough in the audio.

2/With nothing electrical on, in neutral, rev motor, while revving motor any of the sound? Try pressing clutch down while in neutral and revving. Any of the sound?

3/ While driving down the road & the sound there, put car in neutral, does sound go away?
4/ While driving down the road with the noise, put foot on clutch, does noise change pitch or go away?
Please post the answers to these questions & we will have a better idea of the cause.
I am leaning to the thrust bearing or drive shaft bearing or even a stick jammed up under the car, still could be the alt belt though.
Thanks. I will do the following tomorrow (or whenever there's enough driveway space for me to get the car out of the driveway). By driveshaft bearing do you mean the center bearing? I changed that in May, I think.
__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)
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  #10  
Old 12-28-2009, 08:22 PM
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yes, center bearing. spraying a bit of wd40 or something similar may shut thing up. We have stuff called 'dry lube' down here, its like bees wax. it gets rid of belt squeal. Just rubbing a candle (wax) on the belts works too. If its the thrust bearing, sometimes with the extension tube on a wd40 can, you can spray some wd40 on the bearing & shut it up, if thats the case, you will need ti replace it in time. Has the clutch been replaced recently?
__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving
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  #11  
Old 12-28-2009, 08:57 PM
BodhiBenz1987's Avatar
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Quote:
Originally Posted by layback40 View Post
yes, center bearing. spraying a bit of wd40 or something similar may shut thing up. We have stuff called 'dry lube' down here, its like bees wax. it gets rid of belt squeal. Just rubbing a candle (wax) on the belts works too. If its the thrust bearing, sometimes with the extension tube on a wd40 can, you can spray some wd40 on the bearing & shut it up, if thats the case, you will need ti replace it in time. Has the clutch been replaced recently?
It seems weird that the center bearing would squeal, since I just replaced it, but maybe I screwed it up. I'll give it a look. I don't know the history of the clutch, or anything ... I bought this beast a year ago with no records. I'm that daring (or stupid, something like that). All I know is it has the original engine and trans. It does shift very nicely. No grinding or sticking. I never drove stick before I got this car, though, so it's possible my learning process didn't do it any favors.
__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)
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  #12  
Old 12-28-2009, 11:59 PM
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My vote is for the alternator belt needing to be tightened or replaced as suggested by others.
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  #13  
Old 12-31-2009, 12:20 AM
BodhiBenz1987's Avatar
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Just an update: After I got home from work Monday night, I started up the car to experiment. This time I was able to recreate the noise OUT of gear as well, with the clutch in or out, at rpms of about 1200 or higher. So I can rule out driveshaft bearing. I'm really leaning toward belt(s) or maybe the compressor or alternator pulley. Wish I had someone to rev the engine while I stand over it ... that could narrow things down.
Electronics on or off doesn't seem to affect the sound at all.
I hope I can solve this. All my cars are broken now.
__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)
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  #14  
Old 12-31-2009, 12:50 AM
Craig
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It sure sounds like a belt to me. How much can you deflect the alternator belt with your finger (with the engine off )?
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  #15  
Old 12-31-2009, 12:58 AM
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Sounds like belts,
You can rev the motor from under the hood. Just move the linkage.
Tighten the alternator belt & fingers crossed, the noise will go.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving
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