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Serpentine belt clunking


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proof
New User

Jan 18, 2010, 8:53 PM

Post #1 of 9 (7752 views)
Serpentine belt clunking Sign In

98 Chevy Lumina
3.1 Liter Engine
73500 Miles

Last week I put a new alternator in my car. After I had replaced it a low clunking noise (not a squell) was coming from the area of my serpentine belt. I took the belt off and put it back on again and the noise went away. Just now it started making the same noise again. The belt looks fine and I checked the schematic and the belt is routed correctly. I'm stumped please help.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 18, 2010, 10:16 PM

Post #2 of 9 (7746 views)
Re: Serpentine belt clunking Sign In

Hmmm? Clunking noise from a belt driven item is not common to me but let's see here. Did this noise instantly begin with the new alternator and wasn't there before?

If so - the new alternator may not be right or may not be installed properly?? Take belt off again and spin each item you can and see if any aren't right. Sometimes the pulley on the self adjuster goes and might not have liked being touched to do this job. Bearing and mounting of it should not wobble or make any noise if checked by hand with belt off,

T



proof
New User

Jan 19, 2010, 3:26 PM

Post #3 of 9 (7736 views)
Re: Serpentine belt clunking Sign In

The noise did not start immediatly after I installed the alternator but soon after. I double checked the installation and everything seems in order. I took the belt off again and spun all the pulleys. The pulley to the water pump makes a scratchy rusty type of noise which is a better discription than clunking. Does this mean new water pump time or is there something else I can do? Thanks.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 19, 2010, 4:07 PM

Post #4 of 9 (7733 views)
Re: Serpentine belt clunking Sign In

That's enough reason to toss the water pump, IMO. YOU WILL BE THRILLED IT'S THE EASIEST PUMP TO REPLACE EVER MADE! I did one in someones driveway that was leaking badly on a 3.1 with tools (all common care with gasket scraping alloys) I have in my trunk anyway - she was shocked! I said this one isn't worth towing it, I'll be done before the truck could get here!

It sped the job up as I didn't have to drain the system which saved time as it had leaked out already and a parts store within sight!

Apologize if I'm wrong but the noise a water pump might give you at most is hearing some sloshing of coolant - NOT scratchy/rusty sounds. It's a very small pump. I have heard clunks from huge V8s pumps that were ready to let a fan fall off they were so bad.

Note: Without being there, there is no way I can be sure so take any advice with your own judgment.

Here's what it looks like - note just five bolts (I think) after pulley comes off are exposed. 1/4 inch socket set stuff - nice and not expensive too!


Good luck. Feel free to give me a slap if wrong but I'm pretty sure with the description you gave,

T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jan 19, 2010, 7:15 PM

Post #5 of 9 (7727 views)
Re: Serpentine belt clunking Sign In

Try this.........
With the engine running and the noise present, get a real long bar or screwdriver. Carefully slip it in front of the belts in a way that you can apply more tension to the belt tensioner and see if it changes the noise. What I suspect happened is that the belt has stretched just enough that the tensioner is rattling against it's own stop meaning it has run out of range because the belt is too long.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Jan 19, 2010, 7:17 PM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 20, 2010, 8:46 AM

Post #6 of 9 (7715 views)
Re: Serpentine belt clunking Sign In

Excellent HT - that's why you make the big bucks!

Wink

T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jan 20, 2010, 10:26 AM

Post #7 of 9 (7706 views)
Re: Serpentine belt clunking Sign In

Yeah, they just doubled my pay last week. I might look at a new Lamborghini this week.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



proof
New User

Jan 21, 2010, 11:58 AM

Post #8 of 9 (7694 views)
Re: Serpentine belt clunking Sign In

Thanks for all your help. I tried putting more tension on the tensoin bar and it didn't stop the noise so I changed the water pump. The noise has finally stopped. New problem though. I put coolant in radiator to replace what was lost in changing the water pump then I let the engine idle to make sure there were no leaks coming from the new pump. After about 5 minutes the engine temperature and went way up and I shut it off. White smoke was also coming from the radiator. This morning I started the engine again and when the temperature started to rise I turned the heater on and the temp came down immediatly. The white smoke from the tailpipe also stopped. I drove the car around a bit and everything was fine even with the heater off. Back home I let the car idle for another 10 minutes with heater off and no high temperature problems. Is there anything to be worried about now? Thanks heaps.


Sidom
Veteran / Moderator
Sidom profile image

Jan 21, 2010, 12:23 PM

Post #9 of 9 (7693 views)
Re: Serpentine belt clunking Sign In

It sounds like you got an air pocket when you did the pump, very easy to do on those. You just have to keep an eye on the level but if it's back to normal & the system is full, it sounds like you got the air out.........






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