Mechanics

95 3.8

1995 Buick Lesabre

The engine has a tapping noise coming directly from the intake manifold. It sounded like it was a bad valve or a spring or a stuck lifter. I changed out the head, and lifters even though they appered alright. When I started it, it fired right up idoled good, but the tapping was still there. It doses'nt sound like it's anything lower end. It has a plastic fuel induction system on top of the intake, but there's no cracks or defomations. The engine runs good, except for the tapping. There's a horizonal shaft under the intake manifold that looks like an oil distributor the book dose'nt cover, it's on the top of the block; It's the only thing Ican think of that could be bad. I know this is kinda scetchy, what do ya think? Dumbfounded
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Lylewyman
December 13, 2006.



Take off the serpentine belt and start the engine, if the sound goes away then look into one of the belt components, such as the water pump etc. If it still knocks then it possible a wrist pin internally in the engine is making the noise. Hope this helps : )

Tiny
Bootdog
Dec 13, 2006.
8) the horizontal shaft you're asking about is a balance shaft, designed to turn at 1/2 engine speed to absorb engine vibrations. : Wink: need more description of the tapping noise. Does it sound like just one component tapping every revolution, or is it more than one noise?
You may be able to isolate it to a cylender by unpluggine one injector at a time at idle and listen to see if the noise gets louder or quieter on each cylender.
I agree to start by taking the belt off first.

Tiny
Xowey
Dec 13, 2006.
Check your oil pressure, it sounds like no oil is getting to the top on that side.

Tiny
Tccc143
Nov 8, 2007.