Clicking noise in my engine??!! What's that?

[JeepnPit]

It seems lately that when I first start er' up the engine has a slight clicking noise and it's rate moves up and down with the rpm. It sounds like some of those old CJ and Toyota engines. This noise dissapears when the rpm range gets high. It dissapears permenantly after about 5 minutes of driving. Is it the lifters? Low oil? I just noticed on my way back from work yesterday and it got a little worse today. Thanks for your time.

[4ceTen]

It could be the oil. Have you noticed the oil pressure gauge being low? My first guess would be a leaky exhaust manifold. As your engine heats up, the exhaust manifold actually expands and seals up better, eliminating the noise. It sounds very similar to a clicking sound, but is really air moving through a very tiny gap.

Just a guess, hope that helps. You can check them, they need to be at 23 ft/lbs.

[JasonS]

I had something happen like that on my '99. 4.0L
It was coming from inside the engine compartment on the driverside fender well, were that black square 'canister' is. (maybe evaporator)? anyway, it taped on it with a screwdriver (real engineer here), and it went away.
Hasn't come back since. It has all those vacum hoses around it, and a green tag and cap that says evaporator something or other.

[Gettin-Higher]

I just went through the same thing on my 2.5L Turned out to be the exhaust manifold gasket.

[JeepnPit]

Gettin-Higher,
Yeah, Exhaust manifold seems to be the answer. What did you do to relieve the problem?

[Gettin-Higher]

Pulled all the bolts, pulled them away (both intake and exhaust) and pulled the old gasket. My surprise was that whoever did it last was too lazy to put in the right gasket. They put in one that only covered teh intake, and used RTV for the exhaust! The thing had sat for about 2 years before I got it so after driving it for a week, the dried up RTV just blew out. There wasn't even enough to worry about scraping the old off. I just cleaned what needed to be and slid in the new gasket. Put the bolts back and torqued them.. Took all of 2 hours from start to finish..