Last night i had this growling rumbling noise under the hood, its either a pulley, water pump or ac compressor,or ??

the noise lasted for 30 minutes until i shut the car off.

Now the weird thing is i drove the car this morning with ac on for 2 hours straight on the hiway and the noise is completely gone, your input is greatly appreciated.

1998 gs400 with 180k miles

 

Maybe water pump? When was it last changed? Mine lasted to 155k

 

Thanks scottgs300, bu if it was the water pump wouldn't it be constantly making noise?

 

Maybe the alternator?

It can intermittently show signs of going bad until it finally goes. If you do hear it again, pull over and try winding down all 4 windows at the same time. Stand outside while doing this. If the growling sound gets louder it might very well be the alternator.

A method I used which was surprisingly very helpful is...use your phone to record audio...bring it close to each component. Hence bring it close to the alternator then the water pump, then idler pulley, etc.

Listen to the audio after and see where it is the loudest. Just remember the order you did it in.

 

Interesting method, Im gonna give it a try.

The only thing now is waiting for the noise to reoccur, also i noticed that the top pulley 12 oclock, dosent rotate when in idle

 

Not sure how the V8 is set up but you should be able to pinpoint which side the noise is coming from. Then you can use the method of recording audio with your phone on whatever accessories / pulleys run on that side.
Just ensure to put the phone as close to each accessory as possible. By the way I just replace my alternator on a gs300 using this method over the weekend(didn't have a multimeter to test). However ended up getting a multimeter to test after to confirm it.

 

How about the harmonic balancer pulley, are these a known part to go bad?

 

My Uncle had a is300. When his harmonic balancer was going bad, it made the belt squeal.

Since the noise is gone, I wouldn't worry too much now. Would be hard to find the problem without the sound now.

 

I think your right, thanks for taking out the time to reply and to all who read the thread!

 

Well guys, the noise decided to come back today. I just don't want a belt to snap or a pulley to seize up, anyway to trouble shoot it

 

I want to take it to a tech, but would like the noise to be present. The noise just came back after 200 miles of highway driving.