Noisy Motor

[Tobyspaw]

My Cherokee has close to 150,000 miles on it now. 140,000 on it when I purchased it. Anyway it seems to tick and tap alot idling. Rev it up and it runs fine. Oil pressures around 50 on the highway,30 something at idle. Whats my most likely area to check? Pull valve cover? Or is it more likely coming from the bottom end? I can't really narrow it down to a specific area. I guess I'm asking what's typical in a 4.0.

[4.3LXJ]

They make noise when idling.

[nickyg]

That Tap is factory installed I believe.

[bigjim350]

yep sounds normal to me. Mine sounds almost like a diesel when its idling. Been that way since i got it 5yrs ago.

[Cheromaniac]

My Cherokee has close to 150,000 miles on it now. 140,000 on it when I purchased it. Anyway it seems to tick and tap alot idling. Rev it up and it runs fine. Oil pressures around 50 on the highway,30 something at idle. Whats my most likely area to check? Pull valve cover? Or is it more likely coming from the bottom end? I can't really narrow it down to a specific area. I guess I'm asking what's typical in a 4.0.

A mild ticking on a cold engine is normal and is usually caused by piston slap. Once warm, the piston slap stops but then as the oil thins, you may begin to hear a very slight tapping from the rockers. Again, it's normal especially on a high mileage engine and nothing to worry about.
You could try adding some Marvel's Mystery Oil in the crankcase next time you do an oil change. The lifters may become slightly gummed up with high mileage and the MMO often successfully quietens the engine down.
It'll be a good idea to add some fuel system cleaner to your next tank of gas. It'll unclog the injectors and clean the intake valves, making the engine run smoother and improve gas mileage. I recommend doing this treatment at least once/year.

[Tobyspaw]

O.K., well all those comment make me feel a little better. It reminds me of a diesel as well. Just did 3rd oil change since I got it. Using Rotella 15-40, a bottle of Lucas,and a Purolator filter. Thought the Lucas would've quieted it down some,but no.Next oil change I will try the marvel mystery oil. Has new injectors(Ford 4 hole), and fuel pump (Bosch). Thank you all for the replies.

[08grand]

On my 93 wrangler with the 4.0, I was having a drop in oil pressure at idle and when I switched to the k&n oil filter, it stopped. And like everyone else said, when the motor gets a lot of miles on it, it makes noise and shouldn't be fretted over to much.


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[abebehrmann]

In addition to the MMO, I've heard people have good results with adding a can of Seafoam to the oil about 100-200miles before an oil change. The can says it's safe to use for longer than that, but I'm too much of a worrier to leave it in much longer than a couple hundred miles.

[prerunner1982]

I have a tapping noise on my 97 XJ as well and added about a half can or so of Seafoam to the oil and the tap immediately stopped. Of course as I ran it and the Seafoam mixed with the oil the tapping came back, but now mostly just on cold starts. Once warm it goes away or is hardly noticeable.

Not that you are having this problem but I also ran seafoam through the vacuum tube from the brake booster into the intake manifold and it smoothed the idle down quite a bit. Have a can in the gas tank right now.

[nickyg]

I also ran seafoam through the vacuum tube from the brake booster into the intake manifold and it smoothed the idle down quite a bit.

I never heard of this, I'm gonna try it. The only problem I have is after I get the seafoam. what do I do with the seaweed that comes with it.

[4.3LXJ]

I never heard of this, I'm gonna try it. The only problem I have is after I get the seafoam. what do I do with the seaweed that comes with it.

Didn't you know? You extract the Guar gum from it and us it to thicken your home made ice cream :D

[Tobyspaw]

Now that's some stuff 4.3, yup.

[4.3LXJ]

Yup, next time you eat ice cream, enjoy the sea weed :D

[XJ Wheeler]

Might try some thinner oil. That's what fixed mine, and I believe mine was a lifter tick.

[packmule1911]

yep sounds normal to me. Mine sounds almost like a diesel when its idling. Been that way since i got it 5yrs ago.

I've got a little diesel going on as well. None of the other noises get lonely that way. Big happily family.