ColImport

I had experienced a clunk when being stopped while on gear both on reverse or drive. I purchased a mechanics stetoscope and used it while the engine is on idle. When I place the rod tip on the A/C pulley cover I hear the clunk. So here is my question?

How can I find out what is wrong with it?
Could it be just the bearing?
Do I have to replace the whole A/C assembly or just the pulley?

Have anyone had this problem before???


I would apreciate some help...Also if someone could email me a diagram of the whol assembly from the manual i would appreciate it.

Let me know!

2002 2wd 4Runner 76k Automatic

ColImport

thanks for the views anyway

PirateFins

Is the clunk happening when the AC is turned on? Or does make the sound all the time when the AC is off?

Flamedx4

When the a/c compressor kicks on and kicks off there will be a definite clunk. It should only happen when it engages, and then again when it disengages. You call tell by watching it, the inner part will be spinning with the pulley when it's engaged, and will stop spinning (the pulley keeps spinning though) when it's disengaged. Otherwise, it can't make much of a clunk, a bad bearing noise would never be described as a clunk, usually more like a screech for a short while then it stops turning and throws the belt.

ColImport

it makes the sound all the time, no there is no screech....What this could this clunk be then. I hear it the most placing the rod tip on the ac pulley cover

the_supernerd

I replied to your question on the thread "Weird knocking sound." Here is the reply that I posted on that thread:

I had a similar knocking sound happen on my truck. I found that the lower mounting bolt on the alternator was loose and that is what was causing it. Maybe one of your ac compressor mounting bolts is loose.

PirateFins

You could always disconnect the belt on the AC pulley and still listen for the noise. If it is gone then it is the AC pulley, if it is still there keep looking. When you take the belt off spin the pulley and see if you can feel anything or hear anything when the motor is off and not adding noise.

ColImport

thanks nerd, I am going to check that as it could be a possibility.....as far as removing the ac belt...I just remove it and just run the engine normally??? It does not damage anything right??

Mohamed

Just don't run it for very long, like at most 30 seconds. I tend to do that when replacing a t-belt, and to check everything, I run the engine without the accessory belts.

Generally the stethiscope can easily pinpoint where the clunk is coming from. If you said its coming from A/C compressor pulley, it could be one of the mount bolts as others have said.

If you do somehow end up replacing your a/c compressor, I tend to buy the entire remanufactored compressor with clutch from www.aircoparts.com and it is generally the OEM Nippo Denso too and very cheap, probably the cheapest you'll find out there.