Sqeaking until operating temp
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Teching In
Joined: Dec 2019
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Sqeaking until operating temp Hey guys,
My 01 bird (LS1) is squeaking on a cold startup until the engine gets up to full temp, then it seems to fade away. I have tried the screwdriver to the pulley trick to listen to each one, but all of the ones that I can get to sound fine....only one you can't really do that on is the water pump given the space and shape....
Will the water pump make a squeak if the bearing is going out? Would it just randomly change once it's up to temp (assuming the heat is causing something to expand and thus displacing whatever causes the noise)? I have tried a new belt and it makes no difference, pretty sure it is a bearing somewhere.
Any thoughts are appreciated...just want to get a second opinion before I throw parts, money, and time at it.
Thanks!
My 01 bird (LS1) is squeaking on a cold startup until the engine gets up to full temp, then it seems to fade away. I have tried the screwdriver to the pulley trick to listen to each one, but all of the ones that I can get to sound fine....only one you can't really do that on is the water pump given the space and shape....
Will the water pump make a squeak if the bearing is going out? Would it just randomly change once it's up to temp (assuming the heat is causing something to expand and thus displacing whatever causes the noise)? I have tried a new belt and it makes no difference, pretty sure it is a bearing somewhere.
Any thoughts are appreciated...just want to get a second opinion before I throw parts, money, and time at it.
Thanks!
I had that on my LM7. The belt adjustment had crept up to the max although still within tolerance. I put a slightly smaller belt on that brought it to the lower end of range and the squeak has been gone for 500 miles so far.
Thread Starter
Teching In
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Hey Rick,
I'm not sure if this would 100% prove or disprove a belt tension issue, but I took a 15mm breaker bar and put it on the tensioner bolt, fired up the engine, and as it was squeaking I slowly lowered and raised the tension on the belt, from one extreme to the other....the noise didn't waiver in the slightest...no effect.
I feel like if the belt was slipping or anything like that, the noise should have changed, am I wrong? I went from super loose (as loose as I felt comfortable going with my hands in the engine bay lol) and as tight as the highest mark on the tensioner itself.
I'm not sure if this would 100% prove or disprove a belt tension issue, but I took a 15mm breaker bar and put it on the tensioner bolt, fired up the engine, and as it was squeaking I slowly lowered and raised the tension on the belt, from one extreme to the other....the noise didn't waiver in the slightest...no effect.
I feel like if the belt was slipping or anything like that, the noise should have changed, am I wrong? I went from super loose (as loose as I felt comfortable going with my hands in the engine bay lol) and as tight as the highest mark on the tensioner itself.
Thread Starter
Teching In
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Actually, after going back out there and doing more testing, I noticed the crankshaft pulley seems to be somewhat wobbly....I'm not sure what the tolerance is on a stock LS1, but here is a vid of it going (may be loud, sorry lol) Possibly the crank/harmonic balance then? I tried to get the other pulleys in the vid so you can see the difference in movement between the crank and the rest.
Crankshaft Pulley Wobble
Crankshaft Pulley Wobble
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Teching In
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Any thoughts on the video?
Are you 100% sure the crank pulley is wobbling? It looks to be stationary and only moving with the engine. Rubber engine mounts allow some vibration at all times and the crank pulley has marks that make it appear to move when looking at the center. Keeping an eye on the edge doesn't look like its actually moving separate from the block. Keep in mind, these cars don't have keyed cranks from the factory and the LS1 and LS2 can slip at the crank pulley. Easy enough to pull the pulley off for inspection, be sure to get a new crank pulley bolt if you pull it off or switch to a light weight pulley or better damper. It looks normal to me though.
On the original point, my Tahoe does the same thing with a hard to trace pulley squeak or chirp until its gets up to temp. I've replaced the belt and a couple pulleys with no change. Next step for me is to replace the water pump, I'm starting to think this water pump is pushing some fluid through the weep hole and only noticeable after it sits overnight. Hard to verify visually since the weep hole is basically hidden. I might be looking in the wrong spot though.
On the original point, my Tahoe does the same thing with a hard to trace pulley squeak or chirp until its gets up to temp. I've replaced the belt and a couple pulleys with no change. Next step for me is to replace the water pump, I'm starting to think this water pump is pushing some fluid through the weep hole and only noticeable after it sits overnight. Hard to verify visually since the weep hole is basically hidden. I might be looking in the wrong spot though.
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Well I can't tell 100%.... At the beginning of the vid I go from the crank to the idler so you can see the difference. I am looking at the actual groves on the belt track though. The idler is stone solid where the crank you can kinda see the reflective spots jiggle. The idler is bolted to the block so I figured if it was engine movement, I should see it on both pulleys, right? Am I overthinking it? Lol
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From: Central Cal.
Well I can't tell 100%.... At the beginning of the vid I go from the crank to the idler so you can see the difference. I am looking at the actual groves on the belt track though. The idler is stone solid where the crank you can kinda see the reflective spots jiggle. The idler is bolted to the block so I figured if it was engine movement, I should see it on both pulleys, right? Am I overthinking it? Lol
Joined: Nov 2003
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From: Wichita KS / Rancho San Diego
The tensioner bearing is the usual source of this squealing noise. Mine did it for a lot of years in cold weather, but in the past couple of years has gotten quiet again 
