My engine has a faint knocking sound and when i say faint i mean you have to listen for it(i know its not a knocking rod because its not loud at all)i put my ear right next to the heads as the motor idles and i can hear it and the more RPMs the faster the faint knocking noise gets. I have just recently ran the car down my local dragstrip and i did put in 115 octane turbo blue race gas along with having a small crack in my radiator but i dont know if that has anything to do with my problem. The sound IS coming from my heads so im assuming its inside or near my motor. . . . .please help me out :(
Faint engine knock??! on 1990 Ford Mustang GT
by galvas15 in Dayton, OH on July 16, 2010
ANSWER by Visitor , October 29, 2010
dip stick tube could be slightly bent towards crank, allowing it to be hit every time crank turns. happened to me , a faint knock that sounded like it was in the head. put your hand on dip stick tube see if you have a vibration on the tube if so thats it just remove and straighten it out and reinstall.
ANSWER by KeepinitRIL , September 25, 2010
could be a broken spring (pull the valve covers)(check compression) a sticky lifter (seafoam it) a slightly bent valve (check compression) it could be the pcv valve, I only say this because my buddies is making all kinds of noise now, when it started it was very faint (caused by blow by)