My engine ticks and only under very heavy acceleration. Otherwise my engine is pretty quiet and smooth. It's not knocking. Doesn't matter if the engine is warm or cold. My exhaust manifold is definitely cracked in at least one location, but I am also trying to eliminate other, more serious issues since I can't replace my exhaust manifold yet. My muffler also took a dump and my XJ now sounds like a Sherman tank.

Impossible to find the tick because it doesn't do it unless I damn near floor the Jeep.

'92 XJ
4.0L
172k miles
Just did full tune up to the engine.
Oil pressure stays between 40 and 60 at all times.
Just did a Seafoam treatment into the vacuum line. That's how I discovered the cracks in my exhaust manifold.


Any thoughts? Yeah, I know it's most likely the cracked manifold, but in case it is something more serious I want to check it out to be sure. I can live with the manifold for a bit but if something more serious is wrong I need to know.

This does beg the question, how on earth can the exhaust manifold cause a ticking sound such as what I have described?

Is it a consistent popping sound? Or is it just a random popping sound? The crack might be enough to pull in fresh air & causing particles to "pop" in the heat of the exhaust system.

I'm going to say it's an exhaust leak, could be at the flange/cylinder head surface.

It's not a pop at all. It only ticks when I am accelerating or the engine is under some kind of load. The tick is consistent with RPMs and immediately goes away when I back off the gas. The temperature of the engine and the oil pressure haven't had any effect on the tick.

It sounds a lot like my 2006 Tacoma V6 valvetrain noise, but not nearly as loud. If it weren't for the fact this engine has hydraulic lifters I would pop the valve cover and start adjusting tappet clearances. That's exactly what it sounds like - tappets need adjusting.

The manifold is cracked in at least one place. It's a definite possibility (and the most likely one at this point), but I am trying to rule out other more serious problems because I can live with a cracked exhaust manifold for a bit until I get a bit more cash.

Does it sound like a knock? Because awhile back I thought my engine had a knock and it ended up just being the Valve purge. Its located right in front of the pass. side under the hood, mounted on a rubber mount to the firewall. Whenever I stepped on my gas pedal, I'd hear it, and when I had it looked at, the guy said it was just normal operation, and that the rubber mount it was on was just not too "rubbery anymore." I also have a cracked manifold, but I'm waiting for it to get worse so I can replace it with a performance manifold and header.

lol dude go down to the junk yard lol you can get an exhaust manifold for like 30 bucks if not less lol