New squeaking sound from engine

[Skymarshal]

This car has been fantastic on maintenance, but now I think it has a problem. It started having a squeak that was engine RPM dependant. Every so often, the squeak would become a screetch like a dry bushing or bad bearing.

Poking around with my stethescope, it sounded like the sound was coming from the water pump, so I replaced it. No fix.

I then took the serpentine belt off and started the engine. The squeak was a little quieter, but it was still there, and it screetched once too.

So, since I have ruled out all the accessories, what can it be? Bad main bearing? I read something about the crank damper going bad- could that be it? I have run synthetic since buying the car and changed the oil regularly, so I don't know how it could be a bearing...

Car has 130k miles.

 

[Aeroman]

Camshaft position synchroniser? if yours has the hall effect drive unit, the semicircular vane can become bent if the magnet in the sensor comes loose. You may get a P0340 with CEL when the signal fails.

A bearing inside the engine would be unlikely to squeak, since they are under pressure oil fed lubrication. Check the sensor for crankshaft position (CKP) is not rubbing on the toothed wheel.

 

[Foxone]

Thats what mine was, I replaced the whole init (160 bucks) .

 

[Skymarshal]

I just replaced my cam synchronizer, and the squeak appears to be gone! I read up on the problem on several forums, and it appeared to be a common problem with the 3.8L. I got mine from Rock Auto ($37).

Now here's the weird thing. I couldn't ever find the timing marks on the harmonic damper and block, so I did it the old fashioned way with feeling compression at the #1 plug hole and using a long wood dowel to determine TDC. I followed the instructions in the Haynes manual carefully, and when I was done my camshaft position sensor wound up about 90 degrees off where it started! The engine runs great, and no more squeaking.

The alignment tool that came with the synchronizer is supposed to be 54 degrees right of the engine centerline for my engine, and 54 degrees left of centerline for earlier engines. Could mine have been set up with the wrong data? I never noticed any driveability problems- just MPG that seemed less than it should have been. I'm taking it for a longer drive tomorrow, so we'll see if there are any issues with the new position.