Tapping Noise in Head

patrickbmwm3 · 07-12-2004, 04:52 PM

I have a 93 325i (M50) motor which appears to have a tapping noise coming from the head. The sound or tapping is relative to engine speed. From much thought, I have theorized that a lifter is stuck or a valve spring has failed. Could this be a result from such an event?

The car runs great.

Thanks for any input.
Patrick in Atlanta.

kingnine · 07-12-2004, 06:41 PM

Before you consider the worst, check to make sure your spark plugs are tight first. A loose plug will sound just like a failed lifter or a flat cam lobe on these engines.

jonmatar · 07-12-2004, 07:24 PM

just out of curiosity..what grade of gas are you useing?

patrickbmwm3 · 07-13-2004, 04:29 AM

I am using 93 octane.

Appreciate the comment about the plugs, I'll check them. I was going to pull the cover this weekend to look for anything suspect.

jonmatar · 07-13-2004, 07:16 PM

well that definatly rules out detination lol...just curious becuase i put 87 in my car by accident and it was making quite a bit of noise..good luck!

patrickbmwm3 · 07-14-2004, 04:34 PM

Kingnine....Your my HERO! Number 1 plug was 1/2 turn loose. I tightened it down and no more noise!!! How the heck does a loose plug make that noise?

kingnine · 07-14-2004, 08:06 PM

The noise is from the compression wave in the cylinder escaping past the loose threads during combustion. Glad I could help.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

If you let it go for a long time, it will actually erode the aluminum in the head... Not fun!! Glad you caught it before it did.

--DD

patrickbmwm3 · 07-15-2004, 11:10 AM

Obviously, Me too!