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Engine knocking...lifters, piston skirt or something else.

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Old Mar 24, 2011 | 01:56 PM
  #1  
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Default Engine knocking...lifters, piston skirt or something else.

Hey guys,
Newbie here! Same old story...habitual lurker, first time poster...

Car details: 2000 Jeep Grand Cherokee Laredo. 4.7, 195k miles. My Jeep recently started making this noise:


That's not my Jeep, but the noise mine is making is IDENTICAL to that one.

I've scoured the net and this forum, and I'm finding two general things that the consensus says it might be:
  1. A faulty/broken lifter.
  2. A broken piston skirt.

What do you guys think? Some stuff I'm reading says that it's more than likely the lifters, and that other than being annoying, no real harm is being done. Others are saying that it could be a rod or something else gravely serious, and my engine might be ready to self destruct. So for right now, the Jeep is sitting in my driveway, just to be safe.

So is it something I need to get repaired ASAP? If so, any idea on cost if I take it to a mechanic?

Sorry if these are rendundant questions. Like I said, I'm new here, so please be gentle!

Thanks!
James

Last edited by James6378; Mar 24, 2011 at 01:57 PM. Reason: Found a mistake!
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Old Mar 24, 2011 | 02:15 PM
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Year: 1989 xj sport 2dr
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to me that sounds more like a exhaut leak its quiet on the pass side noiser on drivers rods usually are more of a knock than tick
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Old Mar 24, 2011 | 02:19 PM
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An exhaust leak would be making more of a popping sound than a tapping sound. That sounds more like a lifter or pushrod issue. I had a similar noise coming from my 2.8L V6 (different engine but same internals), it ended up being two bent pushrods and a collapsed lifter.

Last edited by Garvin; Mar 24, 2011 at 02:22 PM.
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Old Mar 24, 2011 | 02:31 PM
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From: Broward County Fl.
Year: 1989 xj sport 2dr
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Originally Posted by Garvin
An exhaust leak would be making more of a popping sound than a tapping sound. That sounds more like a lifter or pushrod issue. I had a similar noise coming from my 2.8L V6 (different engine but same internals), it ended up being two bent pushrods and a collapsed lifter.
push rods and lifters are on passenger side where its quiter
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Old Mar 24, 2011 | 02:34 PM
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ol"blue's Avatar
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That video doesn't help because it's a different type of engine entirely.
Does this sound like yours at all?
And Welcome to CF.
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Old Mar 24, 2011 | 02:35 PM
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From: Broward County Fl.
Year: 1989 xj sport 2dr
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this may sound funny and you look a little strange doing it get a three foot pc of hose garden hose works the best start motor and stick one end to you ear the other end move it around untill you pin p[oint the noise it works
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Old Mar 24, 2011 | 03:43 PM
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Originally Posted by freegdr
this may sound funny and you look a little strange doing it get a three foot pc of hose garden hose works the best start motor and stick one end to you ear the other end move it around untill you pin p[oint the noise it works
x2 on the automotive stethoscope. It also works with a screwdriver cupped to your ear and then put the other end up to places on the block. It's an oldschool trick so don't worry about looking bad, a true mechanic whether home or pro would know what's up!

Sometimes if you take off the oil cap for a short moment while the engines running you can hear the lifters rattling away more clearly, and if one is collapsed I could imagine it would making some real racket. In my lil 4-banger you can even shine a light in and see all the lifters doin work to make a quick visual inspection.
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Old Mar 24, 2011 | 04:34 PM
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i vote for a bad wrist pin. I had a bad knock and the wrist pin broke and blew the piston to peices....engine still ran enen with number 4 piston in peices in the oil pan...go jeep
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Old Mar 24, 2011 | 04:45 PM
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From: Broward County Fl.
Year: 1989 xj sport 2dr
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Engine: 12 hole bosch Injectors
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Originally Posted by CenCaliAlum2010
x2 on the automotive stethoscope. It also works with a screwdriver cupped to your ear and then put the other end up to places on the block. It's an oldschool trick so don't worry about looking bad, a true mechanic whether home or pro would know what's up!

Sometimes if you take off the oil cap for a short moment while the engines running you can hear the lifters rattling away more clearly, and if one is collapsed I could imagine it would making some real racket. In my lil 4-banger you can even shine a light in and see all the lifters doin work to make a quick visual inspection.
this works also but the hose will bend around and under and you can see better were you listening
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Old Apr 12, 2014 | 08:32 PM
  #10  
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Year: 2000
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Originally Posted by wildspear
i vote for a bad wrist pin. I had a bad knock and the wrist pin broke and blew the piston to peices....engine still ran enen with number 4 piston in peices in the oil pan...go jeep
i agree with the wrist-pin my is doing the same i thought it finally blew up bot its not getting hot and still has pressure and not burning oil AND ITS STILL RUNNING and wtist pin finally broke and metal piesces but i totally agree with u man
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Old Apr 12, 2014 | 08:59 PM
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Year: 1989 Laredo
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Well the vid is not your engine.
Worth your while to pull the cover off front lower of trans and check to see if flex plate bolts are tight to torque convertor. They can get loose and rattle like a snake. If not corrected one day it will bite your rig.
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Old Apr 12, 2014 | 10:55 PM
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Waz mine, I'd pull the valve cover and take a peek. Rocker pivots can mess up. A tube to your ear with the other end in the oil filler hole might be enlightening.
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