QuestionI have a Mercruiser 4-cylinder, which is a Chevy engine, approximately 1984 era. Last summer the water pump failed and the engine overheated to the point that the automatic cut off switch shut the motor off. Since then, the motor has a clicking sound. It sounds like a noisy lifter, and several people have suggested this as a cause. The noise is almost inaudible at idle, but gets louder with higher RPM's. The motor operates fine besides that - no drop in power. I tried using an oil additive that quiets noisy lifters, however this had no effect. We took it to a repair shop, and they found nothing wrong with the lifters. The noise persists, though. They felt it was a piston slapping and want to install a rebuilt engine. There is no drop in oil pressure, and the motor is not burning oil.
Do you have any other ideas as to what may be causing the noise? Do you feel it will damage the engine to operate it with this noise?
Any information you can give me will be appreciated.
Greg
Answerpiston slap is a possibility. unfortunately, there is no way to tell without tearing the head off of the engine, which might not be a bad idea. an internal tap could be a lifter, like you think, a piston slap, like they think, or a burnt or collapsed valve, all of which could be seen by taking the head off. get a repair manual, and get the head off. you should see the problem right away. oh, just thought of this. before you pull that off, look for carbon around the seal of the exhaust manifold. an exhaust leak will also sound like a lifter. let me know how you make out, and if i can help anymore.
