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View Full Version : Grinding Noise in Auxilary Drivetrain system



Celica89
03-15-2010, 07:54 AM
i have an 89 celica gt-s. I recently went to a mechanic shop to help identify the issue and using a stethoscope he said the noise is because of loose bearings in the idler pulley tensioner. however, when i replaced the idler pulley from my other 89 celica and it creates the same noise. Im thinking the noise may have something to do with the a/c because the car hasn't been run in a year and a half. Is there any possible way that the compressor or components connected to the compressor could be making the grinding noise?

4thgenceli
03-15-2010, 01:06 PM
Normally it's a good idea when replacing items in there (timing belt area) to replace the tensioner, idler(s), and the belt itself.

Any performance issues arise (overheating, loss of power, etc)?

It could be the ac compressor, I've seen ac compressor clutches go out and have a grinding when the pulley is turning. Try disconnecting that belt around the ac and see if the noies gos awy. Youd need eithr a smller belt (to cut out the pump), or just manualy spn the compressor by hand and see if thers binding/grinding.

93celicaconv
03-15-2010, 01:42 PM
Celica89, when you said your mechanic thought it was an idler pulley tensioner, did he say if it was on the timing belt or on your serpantine belt that drives your A/C compressor?

4thgenceli
03-15-2010, 02:26 PM
Celica89, when you said your mechanic thought it was an idler pulley tensioner, did he say if it was on the timing belt or on your serpantine belt that drives your A/C compressor?
HAH..lack of sleep starting to rear it's ugly head.

Completely forgot about that. You can also drop the belt from the idler as well and give it a few spins to see if you hear/feel that noise.

Celica89
03-15-2010, 06:34 PM
Any performance issues arise (overheating, loss of power, etc)?

Actually yes, the acceleration lags until i hit 3000 rpm's, then its normal.

But today i will take off the belt and see if the a/c is the issue.



Celica89, when you said your mechanic thought it was an idler pulley tensioner, did he say if it was on the timing belt or on your serpantine belt that drives your A/C compressor?

It would be the serpentine belt.

93celicaconv
03-15-2010, 06:59 PM
If serpantine, to rule out the A/C compressor, listen to the noise w/o the A/C turned on and the compressor operating. Then do the same with the A/C on and the compressor operating. The pulley on the A/C compressor rides on its own bearings when not engaged, but that ends when the magnetic clutch engages, then the A/C pulley becomes part of the A/C compressor shaft.

So if the sound changes considerably depending upon if the A/C compressor is engaged and operating or not, then you do have an A/C pulley bearing issue. If no change in the sound, the problem is not with the A/C compressor pulley, but somewhere else (a tensioner is a good possibility).

Celica89
03-15-2010, 10:42 PM
Alright so i ran the car without the powersteering belt and without the serpentine belt; however, the car still made the same noise. I asked my mechanic friend and he believes that it has something to due with pulleys inside the timing belt covers. (The thing is recently I had to replace the oil pump because the previous nut came off and the pulley bore itself a bigger hole. [previous owner's did this])

93celicaconv
03-15-2010, 11:28 PM
Timing belt tensioner bearings can go out also. I should know, I had a tensioner bearing fail on a timing belt drive on a VW Passat that had an interference engine. That was not pretty.

I don't know how easy it is to remove the timing covers on your engine, but with your outside serpantine belts off now, you should be able to remove them to see what you have going on down there.

Celica89
03-16-2010, 01:48 AM
very true. ill have to check and see - may take a couple days

Its not too bad; the only problem is how the covers are basically against the body so its its a struggle to get some bolts off (but ive learned tricks of how to get them off).