Clackity, Clackity, Clackity, Clackity...

...pretty much describes a noise eminating from around the front of the engine, under the valve cover

A buddy, today scored an '88 MJ Pioneer with a 4.0 L / Auto, 106k and in pretty decent shape for $1100. When we got it to his house, there was this clackity sound described above, even after the engine shut off... it was the weirdest thing. Just kept clackity-clacken for about minute, then stopped. After a while, we fired the MJ back up again, and the engine made a bit of chatter for a few seconds, then quieted down to it's normal sounding self. Almost seems like it took a while for oil pressure to build up....but just a guess on my part. Unfortunately, the gauges are base idiot lights, so no more clues there.

Any idea what this nosie could be. Oil pump related? Perhaps an anti back flow valve somewhere that's gone awry??? Thanks for any input...

Ivan

What we facetiously refer to here in the north-east as "tacky stippets" -- dirty, sludged up hydraulic valve lifters (sticking tappets -- why do you think Click and Clack call themselves theTappet brothers?).

How does the oil look in that puppy? I'd start off with an oil and filter change, tossing in 5 quarts of 5W30 and one quart of engine flush (or just plain kerosene). Run it easy for 100 to 200 miles then dump it and replace with 10W40 and a new filter. See if that makes a difference.

after the engine is shut off?? i had a nissan 4 cyl that was making a similar sound.... it ended up having an air pocket in the water jacket and it was boiling in the air pocket... but never heard it while running..
mike

What brand oil filter is on it ?, does the oil smell of gas or antifreeze ?
I'd flush it like eagle says for a quick flush or Mobil-1 or Syntec it for a more gentle cleanout.
I think I would also do the anti-freeze, tstat and cap, the normal stuff for a 'new-to-you' jeep. Start hunting a gauged instrument panel also...

I should have mentioned my friend bought it, it had new oil & filter, new plugs, wires, cap & rotor; new water pump, hoses & new anti freeze, and the tranny had the fluid changed as well.

Like I said, it's an odd sound....almost like a check valve some how releasing fluids and clicking along the way. We'll take a closer look tomorrow......Thanks for the leads

If it is making noise after you shut it off then sounds like something in the cooling system. With no mechanical movement I don't see what could make a sound. I have heard metal cooling down when it's hot but thats usually in the exhaust system or something attached to it and you get a tick tick tick tick sound.
A week or two ago my sons YJ had either a noisy lifter at startup or his loose exhaust system which works the downpipe loose from the header flange was leaking a bit when it started up cold but by some repositioning of a piece of steel on the belly plate under the tranny that went away.
Could be air trapped and working its way out. Got a stethescope to localize it ??

Perhaps this sounds a bit dumb, but just a suggestion! If the noise happens only after the key is shut off, look for a stuck (or maybe not) power antenna. They make a click-click-clack noise for several seconds after ignition is turned off, as the antenna tries to retract. The noise telegraphs through the fender, it can fool you...

DaveD, neat idea, I´de forgotten about that power antenna clack clack clack. Mines stuck in the up position.
Maybe the fuel pump relay, is stuck closed (clcik, click, click), I´d have to check the schematic to see if this is possible? Might pull a few relays and see if the sound stops. Faulty grounds, battery to engine, engine to firewall, sometimes cause strange electrical problems. Could be juice from somewhere trying to find ground and actuating a relay from the ground side, through a splice.
Maybe a fuel injector is passing some fuel? They sure enough clackity clack, when they are working.
Might just be an exhaust manilold tick.
A piece of small metall tubing, 18"-24" long, used to listen, often helps to localize strange noises.
There is a wiring glitch in some 88 XJ´s, that is in a recall. Two poles on the fuel pump relay (I believe?), have to be reversed. If pulling the fuel pump relay, stops the sound, get back to me and I´ll look up the procedure for checking/changing the relay wiring.