Q: What would cause a rattling/grinding sound from the front side of the motor in my 2005 Chevrolet Impala

asked by on March 30, 2017

A rattle/grinding from the front of the motor. Unable to know if it's a timing chain or pulley, idler, water pump, etc. The sound seemingly goes away with rpms. I have put a dab of grease on the interior of the ribbed belt which had a very temporary relief. The same goes for a tire crayon. Almost no change when applied to the exterior of the belt. The pulley at the bottom of the motor which I will guess is the crank pulley I'll guess has a counterbalance due to the wobble it has. Is that wobble supposed to be there? I thought it was the timing chain but the sound diminishing with belt lubrication and ultimately the little I know about counterbalance pulleys has me in guessing which isn't a good place. The idler just above the crank also looked suspect. Theres no current trouble codes nor misfires. I haven't seen any metal in the oil either. Thank you for your time.

My car has 112000 miles.
My car has an automatic transmission.

Hello, Most of the time this is caused by an issue with one of the accessory pulleys. Most of the time it is the water pump due to an internal bearing failure. I usually pull the belt off and turn the engine on to see if the noise goes away. If it does then you know that the issue is in one of the pulleys. If not then it may be internal to the engine. With the belt off I would then spin each of the pulleys by hand to see which ones are making noise. This would help me to isolate an repair the issue. If you are thinking of having this problem looked at, consider YourMechanic, as a certified mechanic can come to you to [diagnose why there is a noise coming from the engine]

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