Dropped Rocker Concern...

[slipinkramer]

I'm not new to KJs but I am new to the 3.7 liter V6. I've recently bought and done a little build up on a 2004 KJ and its running really well with 92,000 miles on the clock. It was obvious that the previous owner's maintenance was average at best.

I'm concerned about what I've read regarding the fallen valve seat/ dropped rocker issue, that seems to be somewhat common in this engine family. I've read that the problem is exacerbated when oil changes have been neglected and sludge has built up in the engine. Maybe this is hype, maybe its truth, who knows if what you read about on Google is BS or not??

Is this a concern I should have? Would Marvel Mystery Oil (or some other snake oil) added to the oil or gas be a wise precaution? Is there another measure I should consider?

Thanks

 

[LibertyTC]

If you really are curious, Remove a rocker cover & actually view inside. Install new gasket.
If you have any build ups you will then know.
If it's running good at 92k chances are they probably did regular oil changes.
AS far as ...
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snake oil..I would avoid engine flushes, etc as that can disturb oil galleries with gunk.
I would use a good synthetic engine oil ( as that has really good cleaners in it) and a quality oil filter like Napa Gold #1516 or mobil1 and do the first synthetic oil change at 3000 miles, and then the normal 5000 miles intervals from there.
Considering tons of these 3.7 engines were made many have gone without dropping seat/springs broke etc in other words problem free for twice the miles u have already.
Still if you are that worried you could send the heads out for a rebuild.
I would just do the new oil change and new spark plugs OEM every 20k & /air filter/pcv valve rattle/clean check and go from there to start.
A happy Jeep has quality clean oil and is in a good state of tune!

 

[slipinkramer]

Thanks LibertyTC for the good advice.

It does run well, really perfect in fact. It idled kinda rough when I bought it. Not awful but sort of stumbling around and hunting the rpm a little bit. I tuned it up and in doing so replaced the spark plugs with the same type I found in there, NGK G-Power Platinums. It still idled the same. I switched to some $$$ Bosch Platinums. There was no improvement.

In desperation I bought a set of old school, cheap-ass Champion 434 Copper core plugs for less than 2 bucks a plug at Autozone. I bought them for no other reason than Champion copper core plugs always made my 1967 MGB idle better, way back when I was a teenager.

To my surprise, the Liberty now idles smooth, steady and quiet --just like a dream.

It was suggested to me on another forum that the 3.7 V6 was designed to use low tech copper core plugs and runs best with them. I've decided that makes sense.

 

[LibertyTC]

Yes the copper core work best on KJ's. I just look at the sticker under the hood and used the NGK ones,
Keep in mind though that the coils are powerful and replace those spark plugs every 20 k miles or every 4 oil changes is best.
Regarding idle....The IAC & throttle plate should also be kept clean.
Link to Read I just posted again:
http://www.jeepkj.com/forum/f196/irratic-idle-rpm-speed-55979/

 

[tommudd]

Wouldn't worry about rockers etc. If its been taken care of just keep up the maintenance and keep going . Bought mine new in 04 and its got over 200,000 on it now. If someone said lets head to Alaska tomorrow ( and they were paying the gas and food bill :hat I'd change the fluids, throw in a new set of plugs and be gone

 

[dakar650]

Speaking from experience, I had 200,000ks on my 2002 3.7 before I dropped a valve seat, easily picked up by running horribly and when rocker cover removed a rocker sitting beside it's valve and the only reason it did that was I cooked the motor, knew what I was doing and then paid for it!!! My motor was strong as an ox before hand and after rebuilding both head's seems all good again.

Moral, dropped valve or rockers is most likely over heated motor IMHO.

Cheers

 

[02blue]

Mine was sludged up when I had a #2 exhaust rocker fall off. No valve seat issues just too many short trips. That was a couple years ago. Hasn't happened again. There are some good flush and treatment products out there from BG. I've used MMO periodically with no issues.

 

[slipinkramer]

By the way,

A soft bristle brush and Throttle Body cleaner is a great way to get the throttle body bore and butterfly sparkling clean!

If you do use a brush, make sure it has a metal wire handle so that it will stick to a powerful magnet tied to a string. This way you can retrieve it from the deepest depths of the intake plenum after your fingers slip and it drops 18" down into the bowels of the engine.

Ask me how I know...

 

[CzarKJ]

By the way,

A soft bristle brush and Throttle Body cleaner is a great way to get the throttle body bore and butterfly sparkling clean!

If you do use a brush, make sure it has a metal wire handle so that it will stick to a powerful magnet tied to a string. This way you can retrieve it from the deepest depths of the intake plenum after your fingers slip and it drops 18" down into the depths of the engine.

Ask me how I know...

Good save haha. Sounds like I should just tie mine to a string to start.

 

[slipinkramer]

Its amazing how easily something can slip and tumble down the throttle body bore, and also amazing how far down and around it goes...

 

[yellocoyote]

I'll have to chime in and say the same as some of the others (because I, too, have lived through this experience) - maintenance, maintenance, maintenance! Specifically consistent OCI's and making sure you don't overheat the engine.