Help!!! Screeching engine noise..
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Joined: Aug 2006
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From: Kingwood, Texas
Help!!! Screeching engine noise..
I have an 05 z51 A4 with almost 30k. Brought into shop 2 weeks ago for a chirping noise under the hood. It only occured at start up and very low acceleration (5-15mph). Belt was in good condition but dealer took 1 1/2 weeks to replace belt. Drove off this past Friday and car was fine. Drove 55 miles and when I stopped, the chirping noise was back - and louder. Drove back another 55 miles this morning (Mon) and could hear the screeching noise while driving all the way to 75mph. When I was at idle, no noise. My serviceman was awestruck and didn't have an answer for me.
Anyone have any opinions on what the problem might be?
Thanks, Tom
Anyone have any opinions on what the problem might be?
Thanks, Tom
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Joined: Dec 2006
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From: Dalllas/Ft Worth Area TX
Shouldn't take that long to replace belt, is the water pump possibly squealing? To help water pump seal I put in anti-rust water pump lubricant. Are any other belts loose, tensioners, etc? I would definitely find a new dealer if you can, sounds not to swift.
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From: Spicewood, Texas, USA TX-Texas
You may have a dry accessory bearing...alternator, AC compressor, etc. If the chirping is continuous at idle, your dealer tech needs to take a stethoscope and pinpoint the source. If one of those components freezes up because of bearing seizure, the belt WILL need replacing, and the car will probably have to be towed.
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From: Phila Suburbs 2023 C8 & 2013 650ix
Sounds a lot like the problem I had at 19,000 miles. Look at the crank pulley from the passenger side with a flashlight while the engine is idling. Focus on the ribbing. It should appear stationary while rotating not wobbling. Also, look at the track the belt makes on the water pump pulley that is smooth. You should see distinct stripes where the ribs of the belt have marked the pulley indicating a true running belt. If either of these situations does not exist the crank pulley is not running true and may have to be replaced. Check out my saga at http://forums.corvetteforum.com/show....php?t=1576952
Good luck.
I thought it was the tensioner at first since that's almost always what causes a squeaking belt. But most times you will hear that when you rev the engine and not while running at a constant rpm.
Good luck.
I thought it was the tensioner at first since that's almost always what causes a squeaking belt. But most times you will hear that when you rev the engine and not while running at a constant rpm.
Last edited by Walt White Coupe; Feb 28, 2007 at 10:24 AM.
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Sounds a lot like the problem I had at 19,000 miles. Look at the crank pulley from the passenger side with a flashlight while the engine is idling. Focus on the ribbing. It should appear stationary while rotating not wobbling. Also, look at the track the belt makes on the water pump pulley that is smooth. You should see distinct stripes where the ribs of the belt have marked the pulley indicating a true running belt. If either of these situations does not exist the crank pulley is not running true and may have to be replaced. Check out my saga at http://forums.corvetteforum.com/show....php?t=1576952
Good luck.
I thought it was the tensioner at first since that's almost always what causes a squeaking belt. But most times you will hear that when you rev the engine and not while running at a constant rpm.
Good luck.
I thought it was the tensioner at first since that's almost always what causes a squeaking belt. But most times you will hear that when you rev the engine and not while running at a constant rpm.
And this is an A4 too. I recall that most of the crank pulley failures occured in '05s with a propensity to hit the A4s though of course the manuals were fair game too.
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From: Phila Suburbs 2023 C8 & 2013 650ix
Apparantly I had a failure of the flexible rubber connection between the inner and outer hubs of the crank pulley (i.e. harmonic balancer) that caused the pulley to not run true and damage the belt resulting in the chirping. What made it so hard to diagnose was that when the belts were removed the pulley went back to a "normal" condition and took some more operation before the misalignment returned.
One of the old salty dog mechanics put a large, did I say large, screwdriver down into the ribs of the crank pulley while it was running and chirping and put side pressure on the pulley. While doing this the chirping changed pitch and would even disappear until the pressure was removed. Unfortunately this was done after everything else was replaced that "might" have been the problem.
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......
One of the old salty dog mechanics put a large, did I say large, screwdriver down into the ribs of the crank pulley while it was running and chirping and put side pressure on the pulley. While doing this the chirping changed pitch and would even disappear until the pressure was removed. Unfortunately this was done after everything else was replaced that "might" have been the problem.
One of the old salty dog mechanics put a large, did I say large, screwdriver down into the ribs of the crank pulley while it was running and chirping and put side pressure on the pulley. While doing this the chirping changed pitch and would even disappear until the pressure was removed. Unfortunately this was done after everything else was replaced that "might" have been the problem.
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Joined: Aug 2006
Posts: 85
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From: Kingwood, Texas
Thanks to Walt White Coup!!! Called the technician and told him to check the crank pulley and alternator. He didn't agree that was the problem. An hour later I got the call saying the balancer was bad and they are replacing the alternator. Thanks to all for your help!
