Gasket Leak or Valve? - JeepForum.com
 
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post #1 of 9 Old 08-04-2020, 09:01 PM Thread Starter
blueseasons1
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Gasket Leak or Valve? EDIT

I just bought a 04 WJ with the 4.7. I swear I didnt hear the tapping when I drove it before I purchased it. My wife and son both were there when we bought it and none of us heard the noise. If we had. i would not have bought it. It goes away shortly after running, minutes maybe. But returns as soon as I shut the motor off and start it again. The frequency of tapping increases with speed. Is that a sign that its more likely rather less likely a gasket? Is there an easy way to tell the difference. Seems to be coming from the drivers side. (Initially, I said passenger side). And there isnt any smokein the engine bay as I once said. That stopped. Thanks

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post #2 of 9 Old 08-04-2020, 09:04 PM
sdg3205
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If there’s a little smoke it could be oil leaking from the valve cover gasket. With the tap it could be a broken manifold stud allowing some classic 4.7 Blue smoke special to escape into the engine bay.
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post #3 of 9 Old 08-04-2020, 09:20 PM Thread Starter
blueseasons1
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Valve cover gasket is not leaking. Is it a stud that gets replaced or a new gasket?
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post #4 of 9 Old 08-04-2020, 09:22 PM
sdg3205
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Quote:
Originally Posted by blueseasons1 View Post
Valve cover gasket is not leaking. Is it a stud that gets replaced or a new gasket?


Ideally, all new studs and manifold gasket. May also need to have the manifold checked for straightness.
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post #5 of 9 Old 08-04-2020, 09:56 PM Thread Starter
blueseasons1
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Got it. Thanks.
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post #6 of 9 Old 08-05-2020, 06:16 AM
Double E
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Normally it is the driver's side manifold studs that break but passenger side studs breaking is not unheard of.
A leaking exhaust manifold gasket shouldn't also produce burning oil smoke so there should be 2 issues.
If you're certain the valve cover is not leaking at the back, the next likely place is the oil pan gasket.

'04 Freedom Edition HO & '04 Overland HO (previous '00 Laredo 4.7)
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post #7 of 9 Old 08-05-2020, 09:32 AM
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Here's a thought ... You might have a leaking exhaust manifold (my passenger side cracked and started leaking recently so replaced both). Odds are that your valve stem seals are old and brittle and are letting some oil leak by into the cylinders. Oil burns, comes out the exhaust leak under the hood.

It's a possibility.

I put a pair of Dorman manifolds from Rock Auto on mine. I like them, the heat shields are bigger and beefier.


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ok mostly just repairs, but we are closing in on a lift
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post #8 of 9 Old 08-05-2020, 12:07 PM Thread Starter
blueseasons1
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My son and I went to see the car and drive it. We didnt hear anything. It was cold when we started it. When my wife and I went back a few hours later to buy it. The sound was faint on startup but quickly went away. We drove maybe 40 minutes home with it, turned it off then on. And we heard it loud for the first time. Got up this morning after it sitting all night and the sound was very loud again, but, it went totally away in a minute or so. Didnt hear it when I was driving to the DMV. I dont know enough but it seems to me its oil/valve related. It goes away to fast to have the gasket expand enough for it to stop. I'm thinking it might be a oil supply problem. That smoking I spoke off is not apparent today. Buy the way. Its a 04 Overland, cobalt blue. One owner 136k on it. I paid 4k for it. Things trend hi here in California price wise. I'm taking in for an assessment tomorrow. Depending on what it is, I may try and do the work. Any other thoughts or advice is welcome.
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post #9 of 9 Old 08-06-2020, 11:49 PM
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These 4.7's are know to have cam follower(lifters) issues. It could be those, or the timing chain tensioners. I have heard stories about them getting slack and bleeding off their pressure as the engine sits. Then when the engine is started, the timing chains slap a little bit until the oil pressure comes back up and re-pressurizes the tensioners. But by far, the most common issue i have seen, is the broken bolts for the exhaust manifolds, as stated above. I had to do the drivers side manifold on my current WJ for that very reason.

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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