Infiniti - Bizarre Noises

I've got an 2006 G35 Coupe with a/t, only 4,500 miles.

On a cold start, I hear a strange grinding noise that lasts for approximately three seconds and occurs prior to the car shifting from

1st into 2nd gear. This is the only time that I hear it; after the car gets warm, it doesn't occur again, even when coming to a complete stop. However, if I stop the engine for a few minutes, it will make the noise again.

Also, when traveling 45+ mph, I hear a strange humming noise and I can feel vibrations, that seem to be coming from the wheels/brakes. Dealer has said that the brakes appear "fine" ... any clues?

Thanks!

-John

Reply to
john.karasek
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Is the sound continuous or just immediately after start up? You threw me when you mentioned the part about the shifting. If it's a grinding noise that only occurs immediately after start up and only after the car has sat for a while, I would suspect an oiling problem. I would switch motor oils to a higher quality one and also try a higher quality filter. Some of your cheaper filters omit the check valve that keeps the oil up in the engine when the vehicle is not running. Having said that, some cars are famous for that by design. My Suburban 5.7 did it all the time. I tried everything 20W50, K&N oil filters, etc. I finally read a TSB where Chevy claimed this was "normal".

As far as your humming goes, I would suspect tires before I suspect brakes. I don't know what the O.E.M. tire is on your vehicle but manufacturers have gotten pretty stingy about putting good quality tires (Michelin) on new vehicles. Some of them are pretty crappy. Try having your tires rotated and balanced. If you recently had them rotated that might be the problem. If the tires that are now on the front stayed on the rear too long they might have become feathered. This will definitely translate to noise/slight vibrations when you put those tires on the front.

Reply to
autorepairbot

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