dudeskie

Again another problem arose after my trip. I fixed the alternator, now I hear this knocking noise coming from teh engine bay. Seomwhere near the back of the engine. I turned teh engine off and a long hissing noise began after the engine was turned off. I do not know what is making the tocking noise. The hiss is probably a vacuum leak. Can anybody help me identify what this problem is? Thanks

tnt76vette

Vacuum leaks can cause all kinds of weird things to happen......Find the leak and maybe that will solve your other problem. My $.02 Good Luck!

My69

I've been running down a vacuum leak for about a week now. I finally found it and bypassed it until this week end. What a difference in the motors performance. Just track it down one part at a time. Get a vacuum gauge also, its well worth the money. It will eliminate alot of guessing.

Mike

TedH

When you said knocking, hiss, and alternator, the first thought that came to mind was the underside of the radiator hose that passes near that alternator belt. You may want to check to see if your alternator belt has been rubbing through it. Or, you may have a bad water pump bearing and resulting water pump leak (the hiss)...

If not that, I'd think the hissing noise is engine or trans oil falling onto the exhaust system; resulting from some component failure that contributed the knocking noise...

dudeskie

I think the knocking is more of a miss on a cylinder because it is coming towards the back of the engine. Ways of traking down a Vacuum leak and tracking down a misfire would be greatly appreciated. :thumbs: