2003 LX470 220k miles. Just did the timing belt which included water pump, tensioner, and fan pulled bracket. Belt was also replaced. The belt still squeaks when I cold start it. It goes away after a minute or so. Anything I could do or check for before talking to my mechanic?
Serpentine belt squeak on cold start
- Thread starter RustSchmust
- Start date
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I had similar problem. Replaced idler pulley, tensioner pulley as well as cerpentine belt with the OEM one and all is whisper quite now.
I hate the cold weather squeaks. I have replaced every single spinning part under the hood and still have occasional noises.. I currently have a timing belt related noise only when cold, hasn't made a peep all summer but once it dips below freezing I will hear it again and get sad...cant justify replacing parts again
To Diagnose your problem :
- Remove accessory belt
- Start engine
- Does noise go away?
> Yes , then start to troubleshoot all accessory pulleys. Start with idler, check tension and smooth operation, it should not free spin like a skateboard wheel.
> No? Then grab some tissues to wipe your tears because the noise is coming from the timing belt / related components. +5 points for replacing fan bracket pulley, I've been seeing more and more post about failing fan brackets
( OR, not as effective in some scenarios but could start with just a squirt of water onto the accessory belt and see if the noise changes, but that's not as true of a test and removing belt )
Around 200k all of these spinning parts are getting old and will start to show signs of wear / make noise
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>> Did you do the timing belt because you had a squeak?
- Thread starter
- #5
@Mike NXP I did the timing belt because it had been 13 years and almost 100k miles. The fan bracket pulley was going bad, so that was replaced along with the tensioner and idler pulley. I'm not sure if the belt is OEM, but I might try that. My assumption is that one of the accessories is aging (alt or compressor).
- Thread starter
- #6
Just so I'm clear. To determine whether or not it is an accessory, I need to remove the serpentine belt completely and cold start the truck? If no squeak, then it is either the belt or an accessory. If yes squeak, it is a bad component in the timing belt components.
I am almost certain it's the serpentine belt. 90% of the time it's those two pulleys or the belt. Make sure to get the OEM belt
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This is correct.
However, If your squeak is intermittent that will increase chance of improper diagnosis, if this is only done once.
Your alternator is pulling harder to recharge the battery after a cold start. The noise stops when alternator torque lessens or the belt warms up.
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If all pulley bearings (T-belt and serp), alternator, mag clutch, fan bracket, vane all are good. R&R serp belt.
I find a mechanics stethoscope works well for alternator.
Cycling AC on and off, gives clues as to mag clutch bearing.
I find a mechanics stethoscope works well for alternator.
Cycling AC on and off, gives clues as to mag clutch bearing.