kj217

hello everyone,,

recently my 09 SL63 exibits a weird metallic rattle for few minutes after cold starts,,
the rattle comes from under the car not from engine bay,,
my guess it is related to exhaust but i get a bit worried after reading about cam adjusters and lifters,,

i recorded this video for you to help me identify the source,, first 2 minutes is engine bay then you may hear the rattle from underneath,,

https://youtu.be/DbWIB6G7rNU

thanks in advance,,

sgaar

You are referring to the ticking sound? That is fairly normal. There is a little play in the valve train that goes away when the engine warms up. This is nothing to be concerned about. If your engines consumes a lot of oil, then you might have to get the top end rebuilt (valve guides and seals).

Ah, it is easier to hear towards the end of the clip. No idea what the sound is. It sounds mechanical and if it is external to the engine you should be able to find it if you get a rubber mallet and start banging on stuff (will all dues caution depending on what your hitting). The idea is that if it is the vibrations from the engine that causes one thing to hit another, you should be able to repro that with the rubber mallet.

kj217

thank you for the advice,,
i have checked it and found loose particles inside exhaust mid-pipe (Y) right after primary cats,,
could that be a failed cat? if yes, what to do next?

sgaar

Unless you are having the engine stuttering when rev'ing it, it is most likely not a failed cat in the traditional sense. Typically when you have a failed cat it is clogged and while the engine will idle fine, it will stall when driving it.

If the exhaust is older, it might be some rust that has come lose. You can try to remove the exhaust and see if you can get it out.