I have a 92 SC400 and I have a screeching noise coming from the engine. It is really loud. When I rev to 2000rpm the noise starts. I have replaced the belt, various pulleys, I have a new alternator and new power steering pump. I think the noise is coming from the front of the engine because I have taken off the belt and started the car and the noise disappeared. I have gone to 3 mechanics and none of them have been able to locate the origin of the noise. If anyone has any suggestions please let me know.

 

Probly your main crank pulley. Thats what mine did when it seperated. I could never actually pinpoint the noise. My mechanic found it finally.

 

You said various pulleys, but if you have not replaced the serpentine tensioner pulley then 100% that is the problem. Common. Bad screech usually comes from that.

 

Your crankshaft pulley has rubber to dampen the vibration. Check that and Send Aliga an email to ship you a used one!!!!!!!!!!

 

I've replaced the tensioner and the noise continued. I forgot to add in my first post that when I apply dressing to the belt the noise goes away for a short period of time but always comes back. Sometimes it comes back in 5 seconds other times in a minute. If you have any other suggestions please let me know.

 

Buy a gatorback belt, this is a common problem.

 

like others have said I believe is the crank pulley. Have somebody turn the wheel and rev the engine while you look at the tensioner pulley. It will move up, and the belt will rub the engine. Thought my tensioner was going out but 2 days later the crank pulley fell apart on the highway cracking my fan blade.

 

to confirm where its coming from let your car cool of inside a garage outta the sun. run the car for ten minutes and shut it off. if you have a multimeter with a temperature prob record the temperatures of all the pullys. in theory the hottest pully should be the one making noise. report back to confirm.

 

sharingan I did what you suggested and the pulley went up and down as it should but why are you saying that the increased noise because of the tensioner is the reason for the failure of the crank shaft pulley? Also i dont see the belt rub the engine.

 

Crankshaft pulley. Watch it and rev the motor, you'll see.

 

What am I watching for? Ive done what you said and Im not seeing anything wrong with the crankshaft pulley

 

When mine did that, I could see it wobble all over the place. I had the same symptoms as you. Belt dressing made it stop for a little while.

 

Thanks for the suggestion but I dont think that it is the crankshaft because I dont see any movement when I rev the engine. If anybody has any other suggestions dont hold back.

 

On a 92 SC its most definitely going to be the crank pulley separating. On an SC4 I dont think you can clearly see what is going on after you give it light revvs. After giving it light revvs you should be seeing a little bit of back and for movement either on the pulley or the drivebelt. Pay attention to the drivebelt. I had to replace 3 of these pulleys already. My brother's had the same thing going last week. I took the one off my 1JZ and put it on his SC. Trust me, you dont want to wait until it separates to replace it.

 

I understand what you are saying, but I dont understand how the pulley can stop making the noise when I put belt dressing on it. Also, the sound coming from the engine is a screeching whistling one. I have talked to a couple of mechanics and they have said that the sound that a crankshaft makes when it is about to seperate is a knocking/rattling one.