Jep 4.0 Valve stem seals.

mbalbritton

mbalbritton

#@$%!
Joined
Mar 22, 2005
Location
Lakeland, FL
Alright, my '93 ZJ has 240K+ miles on it, and still runs strong. But the poor girl smokes when you let it idle for any period time over a couple minutes. I'm thinking worn Valve stem seals, maybe even Rings. hey, what do you expect after 240K miles.

Anyway. Question is, What's involved in changing out the Valve stem seals? I've had a set sitting in the Center console and a valve cover gasket under the back seat for about 2 years now, just never got around to it.

anyone have a step by step, or is it not that easy.
 
Having recently tore down a 93 4.0 ZJ with about the same mileage, I hate to say it's probably not the valve seals that are the main culprit. While they do contribute to the problem, the oil control rings just don't stand up to that kind of mileage. Using Marvel Mystery Oil, and Lucas aditives in the oil over about 1 year or 5-6 oil changes did help the problem greatly. MY engine still ran good, but if left to idle for more than a few minutes, would become a smoker. Less so right before the tear down. When i first got the truck @ about 170k miles, It smoked alot, you'd think it had a BBQ grill inside the tailpipe. The engine was taken apart to build a stroker.
 
rebuild and stroke is what I'd like to do, but I don't have the money to do that right now. I just have the parts to do the seals, so I figure it can't hurt.

besies I'm not so sure this Jeep is worth a $1500+ rebuild at this point... so I'll probably just run 'er into the ground, and do my best to minimize smoking along the way.

I'll give the Marvel mystery an dLucas a try. I know the "Engine Restore" seemd to work nice for a while.

thanks
 
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