Hi all
I have a 99 z24 with 120,000kms on it.
The past few days I have begun hearing a grinding noise which is loud when i start the car and then lessens but then comes and goes. It is constant and does not increase with engine speed. It seems to coming from the Alternator area, but the car starts fine. Could it be the AC compressor clutch? Or could it be the timing chain? Not sure how to isolate the problem?\
please help

o man, if you do have snow, it could be ice buildup in the lower mounts, check them, otherwise does anything vibrate?

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its not ice build up. Nothing else vibrates. Not sure what it is.

I would have to say it's the serpentine belt (alternator). Timing chains don't usually grind, they usually make a 'ringing' sound or just fail.

thanks brad, as well from your other post, i could be the compressor doing its thing... but if the fan doesnt kick in, the compressor usually gets warmer and makes a bit more noise, if your cooling fan is not operating, the CEL should come on soon if it hasnt already

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Cooling fan only comes on if car is warm, not when AC is on, like it is supposed to. AC is not working, although its like -8 here anyway, i would still expect the fan to come on when i press AC, but it doesnt.

actually now that you clarify, try letting the car run up to 90 C then try kicking on the ac, winter sometimes makes it not come on unless it really needs to

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I just called my GM dealer and he informs me that the Timing Chain guides may the problem but he want to charge me 100 bucks to diagnoze. Is there any way I can do it myself. Is it easy to change the guides?

what kind of engine is it?

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Hi Matt,
I have a 2.4, DOHC, 1999 year

I'm 110% sure it's your a/c compressor.



Blew it up, build numbers coming soon