I noticed recently that my new to me 1986 developed an exhaust leak. Removed the heatshield and found this




I removed the manifold because Im going to replace it. But Im wondering if running lean caused this. What can I do to prevent this? Or this the way these things go with these cars

 

I have never seen this before in 30+ years of S2 and S3 XJ6 ownership as well as assisting numerous other friends with XJ cars. It is definitely not normal!
I was wondering if it could be an over rich mixture on the third cylinder from the front with the mixture still burning as it exits the cylinder.
That is just a guess. I honestly have no idea.

 

I drove to my local indy, showed it to him, and he told me he’s seen it many times over the years. Typically an injector is dirty or theres a vacuum leak. So it has probably been running lean or like you said, over rich. Im going to install the new manifold and have him service the injectors and look for vacuum leaks. This is crazy though. Ive never seen it either in any car Ive ever owned

 

As said above, I've never seen this on Jaguar exhaust manifolds. A very unusual fault, but the explanation seems logical. It couldn't happen on the carburetted cars, of course.

 

I will be picking up a new manifold in a few days, will be dropping off the car for injector removal and service early june, since I have to travel for a week. Will update the thread as I move forward.

 

I’ve seen this weird condition in several XJ6s, including my own.

I always assumed ….always risky…it was a problem with the castings rather than a problem with the mixture

[shrug]

Cheers
DD

 

I got the replacement manifold today. Will install it tomorrow. Injectors and vacuum leaks are my focus.

 

I got the car running, but started to work on the rust while it’s hot outdoors. I’m leaning towards an intake leak so Im going to smoke test it in a few weeks. In the mean time, its going to get rust repair around both windscreens.