Hi everyone, I have an 81 Toyota Pickup that recently started making this noise like a shard of metal is in the engine oil or something. Did a motor oil flush, and it didn't help. Its fine at start-up, I'll rev the engine for a bit, no sounds, and then when it returns to idle it becomes apparent.

Here's a video of the noise:


I'm stumped and pretty worried. Any clues, suggestions, or advice? Thanks in advance.

 

Well here is my theory, I may be completely wrong but it may help.

When you first start the motor the noise isn't there, so that's when the engine and oil is cold. When the oil is cold you have higher pressure at lower rpm, so the timing chain tensioner keeps the chain tighter, same thing when you rev it a bit, when the oil starts to warm up the tensioner backs off and the chain starts rubbing on the timing chain cover, making that noise. Could it be? Does the sound seem to come from there?

 

Hi gilles, thanks for the reply. It sounds like its coming from just above the crankshaft pulley. I've heard the sound it makes when the timing chain hits the cover, more of a constant clicking, this is sporadic and when I first heard it, I actually thought it might of been one of the bearings on the belt system, but its more of a shard bouncing around inside of a fluid noise.

I'm still getting full power and oil pressure. I went out to listen again, and it actually stops making the noise after a few minutes at idling. then if i rev the motor, it starts up again.

 

Well that's strange! Maybe some lose parts at the bottom of the chain cover? Like broken guides? If you remove the valve cover and look down with a flashlight maybe you will find some clues?

 

Just a thought. It sounds to me that a bearing is going south. You might loosen the belt tensioner, pull the belt, and see how the tensioner bearing feels. With RPM up, it is floating so to speak, but a steady lower RPMs, it gets tighter putting slightly more pressure on the bearings. I have had front hub bearing that sounded like that and it finally locked up before I found what the sound was.

Pull the belt off, start engine and see if it goes away. Then you have eliminated any if internal engine parts if it goes away. If it is still there, then use a stethoscope or long screwdriver put to your ear, and prod around engine to listen for the highest volume. Gives you an idea where to start looking

 

Hey all, as an update it was my water pump- not the crankshaft like I thought. At least I've got clean new oil. It was the taking off the belts that helped pinpoint it, and the water pump impeller was knicking the pump housing with one blade as the engine vibrated, making the sound.Thanks for the help guys.