GT3_Punk

Hi GT enthusiasts, my 996 MK1 GT3 is playing its beautiful rough and mechanical soundtrack at idle - cold or warmed up - like it could not be any better. Only recently I have taken notice of a behaviour and noise which has always been there since I am owning the car, but I did not care about. But now I am curious about it to know what it is... Maybe you can help me. It is as follows: when the engine is started up cold, of course there is the usual Mezger rattle after standing for a week or so. But then it is running perfectly at idle. But when I rev the engine a little, during revs decrease down to idle speed there is some knocking or ticking noise. As soon as engine speed is back at idle, there is no noise except the usual engine / exhaust sound. Once the engine is warmed up, revs decrease to idle without the knocking sound. It is very similar to what you can hear in this video I found - thanks for sharing, Fredrik Jacobsson!
https://youtu.be/t8_6g-DUFJg
I am looking forward to yor feedback. Thanks!

sithot

Hydraulic lifters.

GT3_Punk

Thanks. I believe you are right. Will try a lighter oil grade & with better cleaning properties. If it does not change I will simply live with it.