Hi,

I have a very noticable knock on my 97(3.8), but only at high RPM's. I
had my water pump replaced recently, which I heard from my firends dad
is tricky on 3.8 mustangs. He said he replaced somebodys cam, 96
mustang, because he said the guy got his water pump replaced, but the
guys doing it use a certain brush to scrape the old gasket off, and
pieces from the brush come loose and get sucked into some kind of hole
by the water pump? which clogged up passage for oil to the cam? Anyone
hear of anything like this? Like I said , its only at higher RPM's.
Recently the oil pressure needle flickers rapidly at a stop, but once
gas is givin, it maintains in the middle, or if its in park it stays
where it needs too. Im guessing it ties in with the problem. Any help
or suggestions would be great.Thanks in advance.

 

I highly doubt that a water pump had anything to do with a knock in the motor.But anything is possible, I would be looking in other places to try to find out whats wrong

 

Did the people who did the work tighten everything when they were finished?Check it anyway.A loose pulley would cause a knocking sound and if it's just barely loose it wouldn't make noise untill higher RPM's.