I’ve recently had the engine out but now its back in the car but with new headers. There is a loud tapping/knocking noise from the passenger side of the car which I am hoping is an exhaust leak and not something more serious.
It wasn’t making this noise before the engine was removed and it had the same headers although different gaskets.
I tried using a stephoscope but I couldn’t hear anything concerning from the rocker cover, which I’m hoping means this is likely an exhaust leak?
I also removed the gasket to check for tell tale signs of leaks. It looks like a few of the cylinders, if I understand what I’m seeing, have leaks, however cylinder 2 ‘looks’ better than the others so I’m not sure.
The headers are hedman and they came coated in paint that I understood would burn off during use, which has started to happen (lots of smoke). You can see that the mating flange is actually raised for each primary. I put a straight edge accross the flange and it’s pretty flat.
Anyway, here are two videos. As you will see, disconnecting the plug for cylinder 2 reduces the noise. In the second video, revving the engine seems to remove the noise altogether unless it’s been drowned out by the engine, although I dont’ think this is the case
RESOLVED:
I decided to double up the gaskets on the passenger side. After cranking down the header bolts as tight as I felt safe doing I started her up and let her run for 5 minutes. The noise was gone was means it was an exhaust leak. I will order some decent gaskets but for now I’m happy to call this resolved and move on to the next project.
My Mustang Journey 