Tap/light knock

E

Elheffa

New member
On my jeep i now am getting a light tapping/knocking sound. to me sounds like lifters or rockers can hear it on top but much more on bottom of motor. i have a video of it at idel and small rev up if i can upload here would like to here opinions. Dont want to pull head and replace things and it still be there after put back togeather lol

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Pretty hard to tell anything from that video. What I find helpful is to either go get a stethoscope at the auto parts store or use something like an old broom handle. Put it against the engine in several different areas and then we're up to the broom handle end and listen.

Besides that, how many miles on the engine? My observation is that it leaks a ton of oil underneath there. What is the history on the engine? How long have you had the truck? Do you have an oil pressure gauge? If yes, what is the running oil pressure and what is the idle oil pressure? After the engine warms up are these pressures significantly lower than when cold?

RR

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I got the video to play, finally. work copmuters are not so fun for videos.

I don;t hear the knock either
 
202k miles, only small leak in rms all others were fixed and just havent degreased engine and under carrage. What histry on truck you talking about? Everything i have replaced has been factory minus exhaust manifold i have had for 2 years.

Oil rund 60 when cold 40 idel when hot and 60 when running at highway speed

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You should be good with those numbers.

the flywheel bolts tback out and hit on the trans making it sound like a rod knock though. Pull the trans cover off right behind the oil pan and make sure the bolts holding the torque converter to the flywheel are bice and tight. It happened on two 4.0 jeeps to me so i automatically think knocks are that
 

The noise was real quiet but has been getting louder when i first herd it i checked flywheel all bolts are tight the noise coming from pass sode of motor vid i took was driver side i will post a link for the pass side

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Update on noise:

Replaced all push rods and lifters
After doing so and watching to make sure of oil flow with cover off. my rough idel has all but disappeared. it is much smoother but am still getting a tapping noise but not as loud as before. So i am thinking you are right superj. Had my suspicions that was the case. So time to order lifters, head gasket set, bolts, valves and springs. Figure if i have to pull my head might as well replace everything i can and give it longest life as possible. Jeep has had a nice run with factory parts at 203k miles in 15 years. Super happy with the reduction in tapping noise and it put me into my seat on acceleration for first time today since i had it. Was really surprised at this now looking forward to seeing how it will drive with rest of valve train new as it seems to be my biggest performance problem


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cool. probably drove right by you, ha ha ha. there are a ton of Cherokees and grand Cherokees driving around down there
 

Ok so an update on the noise im hearing

Pulled oil pan off and started to inspect the pistons from under the truck as the skirts all look good and no noticable rocking during movement on the pistons themselfs. As i turn the crank around each cylinder hisses as pressure excapes. So bad rings? Also the base of the piston is moveable by hand and can rock it back and forth on the crank shaft. Is that normal? The cam shaft isnt all silver where the lobes are the tips are silver and from what i can tell all ok going to measure each loab. The back side of the lobes have deposits on them and all have a shiny line going around but not the whole back side of the lobe is shiny on a few. I will post cam lobe mesurements in just a bit

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the piston will slide on the wrist pins, the 4.0 is well known for having a little piston slap when starting. that's normal
 
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