Clicking after shut-off

This is a 95 4.0. Smoked a crank bearing earlier in the year, which scored the crank too much to fix. Got another 95 motor and threw it in, this one only had 98k miles or so.

After you kill the engine, there is a clicking/tapping sound coming from the intake/top of the engine area. We don't have a clue what it is. It will click for about 15-20 seconds and then stop. Just sounds like two pieces of metal hitting each other. It's not overly loud, but it can be heard from inside the Jeep.That's the best description I can think of. Hopefully someone can help me out. Thanks...

Guess no one's ever experienced this?? :dunno:

The manifolds and head expand and contract and a different rate when they get hot. The clicking is probably the metal cooling down and moving on the bolts and other metal surfaces.

I guess that make's sense. Just wierd because I never had that happen with the other motor and this does it everytime.

snowrun95 said:

I guess that make's sense. Just wierd because I never had that happen with the other motor and this does it everytime.

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Check intake/exhaust manifold bolts to make sure they are still at specified torque perhaps. If you didn't use loctite it's possible they backed out.

Mine did that for a while and mysterieous stopped. IT was coming from area of the valves.

my MJ does this (2.5L)

its my IAC motor doin' its thing. does it on startup too.

The only other thing I've ever heard clicking after the key was out was a broken power antenna motor.
But then again - it didn't stop until unplugged.

Thanks everyone. Tons of great ideas. I'm gonna check all the intake/manifold bolts tomorrow. I was thinking it might have something to do with the valves as well, since I have a noise similar to crappy lifters when it's running sometimes.

Thats what I was thinking, Lifters bleeding down after the oil pressure drops to zero. If they aren't too gummed up, a little Marvelous Mystery Oil "MAY" free them up and stop the clicking, if it is that cause.

Re-torquing the manifolds can't hurt and is a good idea for a fresh engine, on a fresh install of the manifolds, the expansion/contraction can cause them to unsettle a bit and the original torque may change on the bolts, so re-torquing the bolts could help.

Finally, most 4.0L exhaust manifolds are welded up steel tubes, a lot of expansion/contraction goes on with that (may be why they crack so often), you may be hearing the rapid contraction of the exhaust manifold making clicking sounds, I don't think there is anything you can do about that.

I just dropped some marvel mystery oil in when I changed the oil on Saturday. I was only seeing around 20 psi for oil pressure so I thought some 10w30 would help that out a little bit since I was running 5w30. After researching it a bit, it seems that 20 psi is perfectly acceptable. Hopefully the marvel mystery oil will smooth this motor out.

When I took the other motor out, I discovered a cracked manifold and got it welded up. I knew they were known for cracking headers and sure enough it was.

lawsoncl said:

Mine did that for a while and mysterieous stopped. IT was coming from area of the valves.

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Seems like the same thing happened today. I don't have the clicking after shut off anymore, but there's still some kind of tick when she's running sometimes. Could be a million things, but hopefully she lasts another 100k