Ticking sound on a c15 acert

Buddy of mine ran into something similar a few weeks back. I didn't get the full story, but I believe he replaced a IVA (cat brake) housing and it went away.

 

Be sure to look for an exhaust leak. I have seen a short section of exhaust manifold gasket blow out not just leak and it will make a ticking sound.

 

That would be the first place I would check.

 

Yes, or a turbo gasket also.

 

It would have to be a real bad exhaust leak to hear at idle, and for him to be getting that mpg, I'd say his intake and exhaust leaks are minimal. The ticking sound that I'm thinking of was a metallic tick,

 

Can't say I disagree but don't hurt to start simple and go up overlooking the little things add to big cost. As I said I have seen a piece of manifold gasket gone and made a noticeable ticking. And it should hurt the performance of an accert noticeably I have seen stranger things. The language barrier is against us as well we all describe things differently.

 

Put a bar against the head and you skull, go from the front to the back,on the head 1/2 way up, if it is a rocker arm or cam you can hear it tick or a crunching sound, Do the air compressor as well. If it is more noticeable on the right side of the motor, use a piece of heater hose against you ear and listen for the loudest area.
Just a thought!

 

My guess = spun a cam follower.