Hey guys so recently I posted about test pipes, cats, headers, and exhaust because I wanted opinions on a non raspy setup. All in all, I decided to ditch the pipes and headers and just throw my cats back on. After doing that, I got an unnerving sound coming from what seems like the back of my head under my throttle body...I'm fearing the worst thinking of valve problems and possibly running a cyl lean. I'm will try to post a video to YouTube and give the link of the noise and hope to hell some legend can figure it out!! Thanks zowners

 

Here's the link guys thanks for anyone who can help or try to help have a good one!

 

Since the sound got louder when you put the mic over the belt area, my first guess would be a bad tension or idler pulley (even though you say it sounds like it's coming from under the throttle body). Yank the serpentine belt and check the pulleys for play, noise, etc.

You could also try putting a long screwdriver or an automotive stethoscope to your ear to pinpoint where the sound's coming from (obviously, I don't recommend you do this around moving parts). If you can confirm that it's coming from under the valve cover, it could be a bad lifter (valve tick) or a slack chain tensioner. Check the FSM for troubleshooting on those.

 

Sounds a lot like it could be timing. Chain slap. But you're only showing the front of the engine. Buy an automotive stethoscope. They're cheap and help a lot.

 

Thanks both of you guys , I work at Mercedes and got one from the shop (auto stethoscope), no real help I could hear it everywhere it seemed like , met a mechanic at a car meet today and he said it was the slack chain like you both said...I drained my oil and ONLY 3/4 A QUART CAME OUT. I changed it about 4K ago but I had no idea Zs ate through oil like that, unless I have a leak. Will let you know how it rides the next few days

 

3/4 omg! oil light never came on? Car ran fine? My heart goes out to you.

 

Well, late to the party but I am about to replace the belt and tension pulley as it makes god awful loud noises and sounds nothing like the video you posted. Good luck with the oil problem.

 

I nearly **** a brick! Car ran fine other than the noise in the video...every once in a while I would see the oil light flicker for a split second but thought it was maybe just glitchin out.

Took the car out last night for about 15 miles and so far everything seems to be solved and the noise is gone! Still worried about the fact my oil change left me with less than a qt of oil, so I checked the bay and all I could find was what looked like oil residue around some places but it looked normal. I'll let you know if I find whose takin me oil haha

 

So far just getting some oil in my baby has gotten the chain slap / e knock to go away whatever it was. Best of luck with your replacements too!

 

We seem to live in a world today where if a 'hood is up', people will say 'what's wrong'. I've had folks say that to me and I respond with'nothing, just checking things over to keep it that way'. Try it!

 

Point the stethoscope to the front timing cover. You would know if it was there. However if there was less than a qt of oil in it then that is cause for various other concerns. The VQ has really tight tolerances and it wouldn't take much to ruin something. Maybe you got lucky and just actually having oil in the engine will save you. In short, the timing chain tensioner is oil pressure actuated and if you were low on oil it wouldn't be able to move out any further when it needed to and that could cause the chain slap. Now with oil it has been able to tighten again. Let's be optimistic and hope for that. Might wanna start Saving money for just in case you have lost some engine lifetime though.... You wanted a built engine and boost anyway right? . Good luck man.