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Unread 01-15-2010, 12:50 PM   #1
zeekracing
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2006 TJ Wrangler 
 
Join Date: Jul 2008
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4.0 Engine Knock

My wife drives a 2000 WJ with a 4.0 and it has right under 180,000 miles on it. It has been a great vehicle other then the death wobble we still have trouble with it. She puts a lot of mile on it and I was running conventional castrol 5-30 in it and was changing oil all the time. I wanted to try the new castrol edge oil that will last 15k or one year. I know I might have trouble with using oil and leaks by going to a synthetic with having that many miles on her ( the jeep lol ). We have about 7k on the oil now and it is still very tacky and looks good. We haven't leak or used a drop of oil. Everything was great until a couple weeks ago the motor started to know when we first started it and ****inued until warmed up. Now It will knock anytime under load. I'm going to go buy some oil conventional oil and hopefully that will help. I've noticed a lot of power loss since the jeep was almost new when we got it. I still have the original cat and muffler on it. I will be replacing them too. Wish me luck. let me know anything that could help. Thanks

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Unread 01-15-2010, 01:20 PM   #2
4Slow9erHybrid
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Quote:
Originally Posted by zeekracing View Post
My wife drives a 2000 WJ with a 4.0 and it has right under 180,000 miles on it. It has been a great vehicle other then the death wobble we still have trouble with it. She puts a lot of mile on it and I was running conventional castrol 5-30 in it and was changing oil all the time. I wanted to try the new castrol edge oil that will last 15k or one year. I know I might have trouble with using oil and leaks by going to a synthetic with having that many miles on her ( the jeep lol ). We have about 7k on the oil now and it is still very tacky and looks good. We haven't leak or used a drop of oil. Everything was great until a couple weeks ago the motor started to know when we first started it and ****inued until warmed up. Now It will knock anytime under load. I'm going to go buy some oil conventional oil and hopefully that will help. I've noticed a lot of power loss since the jeep was almost new when we got it. I still have the original cat and muffler on it. I will be replacing them too. Wish me luck. let me know anything that could help. Thanks
Search for "broken piston skirts". I'm afraid you'll find this to be an issue with many newer 4.0 engines (1999+). I hope it's not that in your case, but the knocking might be an early sign. If the knock gets worse and continues after warm up, that's bad news.
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1997 JGC Laredo 4.0 4x4 99900mi * 0W30 German Castrol since 75k * 225/75/R15 Firestone Destination AT on Ravine rims * winter 235/75/R15 Bridgestone Blizzak DM-V1 * UC suspension * Monroe Reflex Monotube shocks * factory skids * KOR steering brace * rear Addco SB * Magnaflow cat and cat back system * complete 5.9 interior
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Unread 01-15-2010, 02:21 PM   #3
LordHobbit
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I'd change that synth at 6k if it were me.
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93 red ZJ 190k 4.0. Spent more money than I should have ...

Isn't red the only color a vehicle should be?
If at first you don't succeed, use more speed.
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Unread 01-15-2010, 02:26 PM   #4
zeekracing
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Originally Posted by LordHobbit View Post
I'd change that synth at 6k if it were me.
I was really suprised how good the oil still was in it. The oil felt better then regular oil when its new. I think castrol edge is a great oil. It may not have anything to do with the knock issue but I am going to change it later to see.
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Unread 01-15-2010, 02:40 PM   #5
RhinofiedZJ
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Reading these posts scare me as I've always ran synthetics, in all my used vehicles but from what I can see even though the 4.0's are rock solid if you run the i.e. copper plugs, conventional oil, and try to stay away from all the newer age synthetic fluids then they last forever. So with my first oil change coming I was going to use 3 qt. 10w-40 Mobil One High Mileage and 3 qt. 5w-40 mobil one diesel oil since it has more zddp and zinc which supposedly our 4.0's like a lot seeing they have flat tappet cams. What do you guys think? Run all 6 qts of 5w-40 Mobil turbo diesel due to the 1200 vs. 800 gasoline oil ZDDP restrictions? Or run a High Mileage oil like the 10w-40 Mobil One. Or blend the two as I was...It has 10w-40 GTX in it now which I have seen to be a good cheap oil, but I like the Mobil One stuff. I'd really like to try Amsoil just kinda taken aback by the price plus the shipping cost to send me some. If I did get Amsoil I'd go ahead and get tranny, and diff fluid at once so the shipping would only be a one time thing, and get some filters too.
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Last edited by RhinofiedZJ; 01-15-2010 at 02:41 PM.. Reason: mispell and addition
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Unread 01-15-2010, 03:26 PM   #6
LordHobbit
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you can blend them that's fine. I'd stick with the diesel oil. I'm planning on running it when I need to change oil again.
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93 red ZJ 190k 4.0. Spent more money than I should have ...

Isn't red the only color a vehicle should be?
If at first you don't succeed, use more speed.
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Unread 01-17-2010, 12:32 PM   #7
zeekracing
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Well I changed the oil and put some miles on it and the knock is still there. You can hear it a little at idle and its a little louder under load. It gets faster with the motor but stops after about 2500 rpm. I'm going to start doing research on rebuild or maybe stroker or 4.7 swap. I'll see what all the options are and costs. Hopefully it will hold up for a while.
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