Thread: Griding/Clicking Noise at Idle Under Hood

So just a few days ago I started to notice a grinding noise under the hood of my 2000 Grand Prix GTP. It has gradually gotten worse, and now it is much louder than the normal engine noise produced by the car. I hadn't noticed it until my friend remarked, "Jeez man what did you do to your car? It sounds like a diesel." A few of my other friends then agreed. Upon starting my car there is a real loud grinding noise by the engine that lasts just over a second followed by a quieter grinding noise that continues during the entire time in park or idling. I have noticed that it diminishes slightly with the A/C off, sometimes more than usual. It does not grind if I am cruising along, at least noticeably, but as soon as I come to a stop it begins again. It seems louder in park as well. The car has a smooth idle around 800 rpm and it runs perfectly (besides a suspension issue I have yet to address, most likely a CV axle). Does anyone know what could cause this, as well as the things I might be able to do with very limited mechanical experience to solve this problem? Thanks a bunch

Well I took it to a shop because I couldn't figure out what it was. They told me it was a broken flywheel and quoted me $1000-1100. Does this sound about right?

Well how long would you expect the job to take a good mechanic? It would most likely take me forever and I'd probably mess some stuff up. Not to mention I probably don't have half of the equipment needed to complete the task. I just wanted to know if the flex plate / fly wheel seems like it would be the problem and that $1000 is a reasonable charge for a job like that. The car still shifts fine and I don't feel any power reduction or tranny slippage so I wasn't sure, but it did sound like the sound was coming from below the engine. If the part they order is somewhere between $50-100, could it really take 10-15 hours of labor?

Well I just realized that my car doesn't even have a flywheel. I drive an automatic... Looks like I will be finding another new mechanic. I have absolutely THE WORST luck with cars and mechanics. A second opinion is always nice anyway.

Well I'm aware that I have a flexplate and that a flexplate is essentially a flywheel but the mechanic told me he was ordering a flywheel for my car. Just seems like a big mistake for a seasoned mechanic.

Alright thanks. What do you think would be a reasonable cost for the job?

Thanks. I am taking it to a engine/transmission shop tomorrow. I am going to get a second opinion and have them fix it while I am out of town. I would be happy to buy the flexplate from Bill but since my GP is my only car, the repair is pretty time-sensitive. They said they would be able to have a flexplate in a day at $55-60 and with the labor, it should come to about $700. The guy was very knowledgeable and said he would have to take the starter out to verify that the flexplate is the actual problem. He was planning on dropping the tranny rather than taking out the motor.

How do you guys think my flexplate cracked anyway? I stumbled upon an article yesterday that said GM improperly alligned the flexplate in their 3.8L motors so they wear down from age, but I just hope this flexplate isn't a sign of a failing tranny or bad starter as well.