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 KeepinitRIL on 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)
ANSWER by Visitor on 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.