Funny noise from top of the engine

My 02 tb soemtimes idling makes a "clank" noise as a loosen chain or something coming from the head, approx.
Mechanic says to wait and see what happens :grinyes:, hope nothing bad. As soon as you give gas noise disappears..
Suggestions?
Thanks

Take the oil filler cap off and see if it is more noticeable, if so I am looking into the same thing on my 02 TB with 140k, and no it shouldn't just be driven that way if it is internal.

Loose/broken timing chain tensioner or spring?

I was thinking about the chain, hope is not. I also don't hear this noise every time engine is on, I'll open the oil cap for sure as soon as it pops out. Let me know in the meantime if you find out more.
Thanks

It doesn't seem more noisy if I open oil cap while it happens. What kind of tensioner does it mount for the chain? Hydraulic? I was thinking: noise at idle, low oil pressure because of slow pump at 700 rpm, maybe old tensioner, chain shakes a bit and does this noise... Could it be?

Mine is a sort of low pitched whine, if I remove the oil filler cap get my ear down to it, I can hear it coming from the front of the engine. Yours may be different take of the serp belt see if it goes away. If it is a metallic clanking as you say, better get into it now!

Still doing this noise once in a while.. Can't really do any check taking off the belt because it's soo quick to disappear by itself. Is it a long/difficolt job replacing the chain tensioner?

Still doing this noise once in a while.. Can't really do any check taking off the belt because it's soo quick to disappear by itself. Is it a long/difficolt job replacing the chain tensioner? Yes!! be sure before you jump into this!

It's getting worse so I hope I can get it finally. The only thing I can say is that noise exists only at idle and warm-hot engine, if you even barely touch the gas with your foot it disappears. Is there a way to raise a little bit idle by computer?
Is the timing chain tensioner hydraulic? Wrong engine oil? I use to put 10w30 fully syntetic...

To help pinpoint where the noise is coming from, use a long metal rod as a stethoscope. Place one end on the engine (away from moving parts) and the other near your ear. You should hear it clanking loud when you are close. To inspect the front of the engine, you can remove the serpentine belt and cooling fan temporarily. Good luck!

Yop, I actually have a stethoscope for mechanics purposes but I never made it to find out where this bell-noise comes from!:banghead:
I'll let you know for sure what happens even if it will take a while. I don't understand why this noise if effected from low rpm.
Thanks