robertbartsch

Before my head and cam change my motor squeeled like a pig. After the head and cam swap it still squeels. From everthing I can tell, the sound is comming from an accessory pulley.

Some times the sqeeling is there, other times it is not; it does not vary when the AC or power steering is used, however. It really does not vary with the RPM either. It seems to be louder after a car wash or rainy day.

I have changed the following pulleys/parts with no help:

1. Power steering (new pump w/ old pulley pressed on)
2. Main idler tensioner pulley - pulley only (Thunder Racing unit with larger pulley shoulders - same main tensioner was re-used)
3. New belts (AC and main belts)
4. pulled the crank pulley and re-installed the stock unit after cam change (no difference in squeel)
5. New H2O pump (no change in squeeling)

I have a stethascope and I placed it on all the pulleys when the motor is on and the squeeling is ocurring. Unfortunately, I can't definatively identify the bad pulley or other cause. I suspect it is the AC tensioner pulley, however. I am assuming the two tensioners (not the tensioner pulleys) cannot make the noise since they only hold the pulleys with a spring-loaded arm; right?

Any other thoughts on how I should try to identify the mistery squeel?

Thanks...

triumphman

here's one for you, try removing the oil fill cap and see if the noise goes away,,i had a car that had a mystery squeal and it turned out to be a vacume leak from one valve cover gasket [there's alot of vacume in the crankcase with no load]

good luck.

robertbartsch

Really? Thanks; I'll try that.

Would this only identify a vacume leak in the passanger side head or will removal of the filler cap equalize both sides?

What other symptoms does a vacume leak have; the car runs great and pulls hard?

When I had the heads off , I obviously removed the valve cover gaskets; since they are re-usable I just bolted them on again... Since the car squeeled BEFORE the head and cam swap I am inclined to suspect the plastic intake manifold leaks rather than the valve cover.... In addition, the new heads are milled .055 which changes head/intake alignment slightly....

Come to think of it, the squeeling did occur a few months after I installed a new LS6 intake manifold; do you suspect the gaskets on that unit are bad?


Do the valve covers and the intake manifold pull the same vacume?

Thanks...

1gen

iTrader: (1)

It's always in your best interest to get new gaskets even if they are re-usable....

robertbartsch

Any idea on how much vacume I should be pulling at idle? If this is low I asssume it has a vacume leak; right?

30th TA 0219

probably tensioner pulley..get the ASP deeper groove one with the replaceable bearing!

triumphman

did you try removing the oilfill cap? did the noise go away? if the squeal went away then you hane a vacume leak to find it spray brake cleaner at suspected areas[valve covers,intake where it meets the head also there is a round piece where your map sensor is connected it is secures withn a o ring i have seen them leak vacume on occasion i allways smear some silicone around it when i do intake swaps. also to eliminate accessorys and pullys just take the belt and fire it up breifly this test could lead you in a new direction. good luck

robertbartsch

I haven't tried removing the oil filler cap yet.

Dump question: If I spray the suspect areas with brake cleaner (will silicone work too), how does this detect a vacume leak? Do you see bubbles around the leaking area?

I also installed an oil catch can in the PVC system; is this often a cause of vacume leaks too? I beleive the screeching started after I did the LS6 intake swap but before the oil catch can, new heads, new cam, etc.

If it does not have a vacume leak, I suppose I will replace the AC tension pulley. They cost $80 from the General (what a ripp off)

As retaliation, I will participate in the piston slapp class action litigation (tit for tat); right?