Nasty tapping sound

JacksJeep · **Posted:** Thu Dec 28, 2006 8:09 pm

My wife's GC just developed a nasty tapping sound from the engine that increases in frequency with an increase in RPMs. But performance is not noticeably affected. I'm guessing value tap. :?:

Any other possibilities?

LiLredLibby · **Posted:** Thu Dec 28, 2006 8:17 pm

Year..Engine size..Mileage?

JacksJeep · **Posted:** Thu Dec 28, 2006 8:30 pm

2000 GC, Six cylinder, 160+ thousand (hence my guess it is a valve).

4wdParakeet · **Posted:** Thu Dec 28, 2006 8:49 pm

LIfters

Parakeet

LiLredLibby · **Posted:** Thu Dec 28, 2006 9:13 pm

X2....Jack with this kind of mileage theres not much of a doubt the lifters are going to be a little slugged up inside.The Gunk company carries a product called Motor Flush.Use this per instructions,then put this older engine on a perscription of Max Life(valvoline)motor oil. It's designed for higher mileaged engines.At my job I have serviced several engines with alot more miles than that.I once serviced a S-10 pick-up with a 2.5 liter 4cylinder that had 780,000 before the guy retired it.He said the day it turned over 100,000 miles he used Max Life and the rest is history...Hope this helps. :idea:

DarbyWalters · **Posted:** Thu Dec 28, 2006 9:14 pm

You might also find that a "wrist pin" that locates the piston on the rod is the culprit.

LiLredLibby · **Posted:** Thu Dec 28, 2006 9:30 pm

Oh.....I thought he said tapping, not knocking?

2372ighost · **Posted:** Thu Dec 28, 2006 10:16 pm

My vote is a lifter FWIW

4wdParakeet · **Posted:** Thu Dec 28, 2006 10:23 pm

I would say it's about an 80% chance it's a lifter. In a year I can remember replacing at least 4 sets of lifters on higher milage 4.0L's.
I'm thinking it's pretty common.

Parakeet

tulsa · **Posted:** Thu Dec 28, 2006 11:42 pm

This might be a good test of Marvel Mystery Oil. I have used it in the past to solve noisy valve trains. Click and Clack did a spot earlier this year where a caller told of using 2-cycle gas mix in an emergency and it a fixed similar problem.

sleeve84028 · **Posted:** Thu Dec 28, 2006 11:58 pm

Yummy - sticky lifter!

LiLredLibby · **Posted:** Fri Dec 29, 2006 12:00 am

tulsa....I have also heard others speek highly of MM oil......Which reminds me Jack;another great product that i know works well is Engine Tune made by a company called Justin Brothers.With this product you just change the oil and add the product,without going thru flushing procedures.If you can find it you will not believe the results. :wink:

Evenstill use the Max Life,it has additives in it to keep gumm from building back up.

DarbyWalters · **Posted:** Fri Dec 29, 2006 12:08 am

LiLredLibby wrote:

Oh.....I thought he said tapping, not knocking?

The wrist pin will sound much like a hydraulic lifter noise. I would check a few things:

In the oil filler tube, Do you have some "sludge or varnish" build up? If so, pull off a valve cover and see if you have some very thick sludge. This happened to my 2002 KJ...caused from short trips of city driving. I found two valve spring cracked. I replaced the valve springs, lifters and cam after cleaning up the area...still had tapping. Pulled the oil pan and removed piston/rod assembly and found the play on a wrist pin. Did a light honing from underneath and replaced with a new rod/piston/ring...no more tapping.

LiLredLibby · **Posted:** Fri Dec 29, 2006 12:25 am

DarbyWalters wrote:

LiLredLibby wrote:

Oh.....I thought he said tapping, not knocking?

The wrist pin will sound much like a hydraulic lifter noise. I would check a few things:

In the oil filler tube, Do you have some "sludge or varnish" build up? If so, pull off a valve cover and see if you have some very thick sludge. This happened to my 2002 KJ...caused from short trips of city driving. I found two valve spring cracked. I replaced the valve springs, lifters and cam after cleaning up the area...still had tapping. Pulled the oil pan and removed piston/rod assembly and found the play on a wrist pin. Did a light honing from underneath and replaced with a new rod/piston/ring...no more tapping.

Oh you could be right,but I guess we are all just doing some wishfull thinking here.But,if he tries a flush and new oil and it don't fix it, atleast he'll have a clean engine for the rebuild :lol:

JacksJeep · **Posted:** Fri Dec 29, 2006 8:06 am

Thanks, so much for the advice. I'll get at it this weekend.

ATXKJ · **Posted:** Fri Dec 29, 2006 10:37 am

One way to check is to take any metallic rod (old antennas are great) and touch it to different point of the engine - with the other end touching your ear - makes an engine stethoscope (sp?) so that you can pinpoint the source of the noise - you should be able to distinguish top of the engine noise from bottom of the engine noise, just watch for moving parts.

If you do decide to rebuild - they sell a stroker crank for the 4.0 - makes it a 4.6 and improves the low end torque......

Nasty tapping sound

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