Help diagnose new problem: screeching noise (post timing belt change)
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AudiWorld Senior Member
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Help diagnose new problem: screeching noise (post timing belt change)
<center><img src="http://www.vboston.net/a8_engine/images/a8_engine_05.jpg"></center><p>
(here's an earlier pic of the process, just for fun)
This is all for the same damn car... the A8 4.2 5V where I changed the timing belt, with a whole lot of other parts like one of the cam chain adjusters.
It ran great for a day or so, long enough to figure out that it needs a new control arm (damn money pit! =).
Now the engine makes a loud screeching noise. It sound a lot like a power steering system that is low on fluid, except that it's not related to the steering. The loudness is in direct proportion to the engine RPMs, regardless of gear.
What could it be?
Also, there seems to be a new oil leak from one of the valve head cover gaskets. It leaks out the back, and onto the exhaust manifold, making some smoke, but that is probably unrelated.
Thanks!
(here's an earlier pic of the process, just for fun)
This is all for the same damn car... the A8 4.2 5V where I changed the timing belt, with a whole lot of other parts like one of the cam chain adjusters.
It ran great for a day or so, long enough to figure out that it needs a new control arm (damn money pit! =).
Now the engine makes a loud screeching noise. It sound a lot like a power steering system that is low on fluid, except that it's not related to the steering. The loudness is in direct proportion to the engine RPMs, regardless of gear.
What could it be?
Also, there seems to be a new oil leak from one of the valve head cover gaskets. It leaks out the back, and onto the exhaust manifold, making some smoke, but that is probably unrelated.
Thanks!
AudiWorld Super User
Joined: Aug 2001
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Did you replace the serpentine belt? Get oil on one of the pulleys?
It sounds like a belt squealing, and the only belt on your engine that can squeal is the serpentine belt up front. Also check to be sure that the serpentine belt tensioner is in good shape.
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Joined: Oct 2000
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A defective timing belt idler, if replaced? Overly tight timing belt?
If the noise persists when you run the engine without the serpentine belt, do all the idlers and rollers turned by the timing belt turn smoothly? Water pump?
Got a stethoscope or heater hose to narrow down the origin?
I once made my Golf whine by slightly overtensioning its manually tensioned timing belt. The noise was more like a power steering pump than the shriek of a slipping belt. Any chance of having missed a step during the belt tensioning, such as inserting the 5 mm drill bit, which would result in too tight a belt?
Tom
Got a stethoscope or heater hose to narrow down the origin?
I once made my Golf whine by slightly overtensioning its manually tensioned timing belt. The noise was more like a power steering pump than the shriek of a slipping belt. Any chance of having missed a step during the belt tensioning, such as inserting the 5 mm drill bit, which would result in too tight a belt?
Tom
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