Terrible rattle like sound from exhaust

[Tang206]

Hey all, new to the forums and starting to get more into doing maintenance and repairs on my car myself. Was hoping someone could help me with a diagnosis...

On a cold start there is a terrible rattle like sound coming from the exhaust. It is not consistent though. It will be really loud, then quiet, then somewhat loud. Soon the exhaust sound goes back to normal. The sound will also happen at varying rpm speeds, generally at the towards higher rpms and only for a second.

Note: No aftermarket work has been done to the car that I know of. It has 44k miles.

Here is a video of the sound. In the video its at its loudest just a FYI

[///M Power-Belgium]

Originally Posted by Tang206

Hey all, new to the forums and starting to get more into doing maintenance and repairs on my car myself. Was hoping someone could help me with a diagnosis...

On a cold start there is a terrible rattle like sound coming from the exhaust. It is not consistent though. It will be really loud, then quiet, then somewhat loud. Soon the exhaust sound goes back to normal. The sound will also happen at varying rpm speeds, generally at the towards higher rpms and only for a second.

Note: No aftermarket work has been done to the car that I know of. It has 44k miles.

Here is a video of the sound. In the video its at its loudest just a FYI

The rattle noise in your video is loud and clear .And your issue is pretty simple .

1-You have the Inconel ///M-Performance exhaust

2-The Inconel lightweight chrome-nickel alloy is prone for cracks

3-You hear the rattle vibrations of the cracks

Check your exhaust for cracks like this ...

[Tang206]

Thanks for the reply. Yep there is a crack clear as day on the left one. Really would like to avoid buying a whole new exhaust system. Maybe can research replacing only part of it or buying a different exhaust system. I have had the car for 4 years and it just happened but I don’t really want it to happen again if I buy the same type of exhaust. What would you suggest?

[Dpc2u]

Inconel can be tig welded, you would just have to find a good welder in your area, and have them address any hairline cracks in addition to what you can see. May or may not be worth the fix to you.

[drrust]

The Inconel can be welded. If you're in Seattle there should be some welders with experience from the aerospace industry. Some weld up the cracks others overlay a piece of material over the crack. If you search 'MPE' you should be able to find examples.

It is the Inconel 625 alloy. They need specific wire. One can order material from McMaster Carr if they want to make a patch.

[monterey]

It's incredible what a small crack can sound like. I had a crack in one of my welds. It was a simple fix, the shop didn't charge me a dime and only took him 30 secs. The result was day and night.

[drchuck72]

I was getting a slight noise on acceleration which would go away at higher RPM.

Yesterday, the car went into limp mode, which went away after I shut the car down and restarted. Later on, I got an increased emissions check light. That didn't go away.

I got it checked out this morning at my mechanic shop. He hooked it up to the OBDII and there was a misfire on bank 2. Turns out, I had an exhaust leak due to some bad exhaust gaskets at the headers. Also explains the smell of gas on cold startups. So once it gets fixed, should solve those problems and improve performance and fuel economy. Yay.

Could've been worse. When the car went into limp mode, my mind went immediately to Throttle Body Actuators. Yikes.

[Tang206]

I found out it is hard to find someone that welds inconel. So I think I am just going to use the opportunity to upgrade exhaust systems. Now just to listen to endless videos on how they sound until I choose.

Thanks for the help everyone.