noisy lifters

skylinergtr · Jan 10, 2010

i tried searching but i know these engines are probably known for noisy lifters, but my 91 XJ 4.0 4X4 5spd has pretty loud noisey lifters when engine is warmed up. Oil is kinda of dirty (plan to change it soon) and the level is fine. Engine runs like a champ (170k miles) and has plenty of power. Is there anything to reduce the noise like some sort of additive or does anyone recommend a different grade of oil other than 5w-30 or 10w-30?

thanks in advance.

MJR · Jan 10, 2010

Some of the 4.0L's may have piston slap (piston bores slightly out of shape due to worn manufacturing equipment) depending on year (I don't remember which).

Other possiblities are loose torque converter bolts or wrong viscosity oil. 10W30 is what I run and I think it was the recommended viscosity. Depending on the climate you can run a thinner or thicker oil.

skylinergtr · Jan 11, 2010

it could be piston slap as you said. never thought of that. I dont know what the viscosity of the oil is inside it right now. The PO did the oil change but im guessing its 5w-30 or 10w-30. I was thinking about 10w-40 to put in but who knows if it makes a difference.

heyhar · Jan 11, 2010

Most piston slap that I'm familiar with occurs in '96 and newer, owing to a change in piston construction, although it can happen from wear in older ones. I had to change the lifters in my '92, at about 130k miles. It would tap shortly after a cold start, beginning around 90k miles, but got progressively worse, to the point where after a high speed run on the Interstate, the idle would be lumpy, and it wanted to stall. I put in new rocker arms, as some were getting beaten by the pushrods. Helped a little, but just reinforced the fact that some lifters were not pumping up properly. Replaced them July of '03, car now has over 200k on it, still runs great. It's a real pain to do, as the head needs to come off. Try to make sure it's what you really need before going through the trouble.

MJR · Jan 11, 2010

I tried a different viscosity once and it seemed the motor was noisier so I went back to 10W30.

t-frady · Jan 11, 2010

i read on naxja some where that marvel's mystery oil might help
i am going that route now
mine is 89 5spd

MJR · Jan 11, 2010

heyhar said:
Most piston slap that I'm familiar with occurs in '96 and newer, owing to a change in piston construction, although it can happen from wear in older ones. I had to change the lifters in my '92, at about 130k miles. It would tap shortly after a cold start, beginning around 90k miles, but got progressively worse, to the point where after a high speed run on the Interstate, the idle would be lumpy, and it wanted to stall. I put in new rocker arms, as some were getting beaten by the pushrods. Helped a little, but just reinforced the fact that some lifters were not pumping up properly. Replaced them July of '03, car now has over 200k on it, still runs great. It's a real pain to do, as the head needs to come off. Try to make sure it's what you really need before going through the trouble.

Had one two years ago that wore through a lifter so it would not pump up. We did it in the campground.

noisy lifters

skylinergtr

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MJR

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skylinergtr

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heyhar

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MJR

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t-frady

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MJR

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