Straight Six lifter noise

[Shaun @ Tru6]

In my quest for cheap winter transportation, I've found a Grand Cherokee, 190K, with lifter noise. Haven't seen it run yet, but it's a one owner truck and looks nice in the pics. Owner says it has lifter noise, in the way that someone told them it has lifter noise.

is this a simple matter of running a solvent like some gas or Marvel through the crankcase to clear the jounral(s) or is it symptomatic of something bigger?

[Rot 911]

Every Jeep 4.0 inline six has some amount of lifter noise. It is inherent in the design. If you have never heard one before you would swear there was one or more stuck lifters. In reality the 4.0 engine is damn near indestructible.

[Scott R]

Amazing, I knew which engine this was just from the thread title. Learn to live with it, like Kurt said it's normal. I was at 290k on my 92' before I had to replace the valve train, even then it could have gone longer.

[Shaun @ Tru6]

Thanks Kurt. I've been driving my 97 for a year and half now on only 5 cylinders. tows fine too, so I'm a big believer in the motor. Bought it with a blown head gasket planning on putting a yard motor in, but tried some Steal Seal first which worked great, but the number 1 cylinder has no compression...odd thing is it doesn't burn any oil or smoke.

I've never heard any noise coming out of it though.

Anyway, it's been a great $500 truck and gotten my $ worth, but it's starting to go down hill and would rather get another $500 truck than put a new motor in this one. between the trans just starting to slip when cold AND the front just starting to grind (like boulder on boulder sound) combined with no O2 sensors for the past year (need any propane?) which means I probably need a cat too...If I can get $300 for it as is, I'll be ahead.

Will post what I hear when/if I see it.

[lm6y]

I bet it's piston slap. Most of what everyone calls lifter noise on the 4.0 is piston slap. The factory even made the last generation (2000 model up) with teflon butttons on the piston skirts.

But yeah, if a 4.0 isn't making horrible mechanical noises, that's when you need to worry.

[BeyGon]

You could run 1/2 qt of transmission fluid in the oil and it might clear things up abit. I have done it on lots of different six and even v8 motors. I think it works great and is cheaper than all the additive stuff.

[on2wheels52]

When I worked at the gas station a back hoe owner put a quart of ATF in at every oil change in his pick-up. I haven't adopted his practice but it worked for him.
Jim