valve cover gasket leak help

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  #1  
Old 05-12-12, 02:41 PM
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valve cover gasket leak help

The valve cover gasket(s) on my 93 Jeep Grand Wagoneer (with V8) are seeping/leaking enough to be causing a rather soaked area underneath, and obviously need attention. For one thing, I noticed the engine oil level in this vehicle (which I just recently acquired) has nice clean looking oil but was overfilled by at least a half a quart. Could that in itself possibly cause excess pressure or whatever and at least maybe contribute to the leak/seepage I mentioned at the valve cover gaskets?

I was reading that when oil pools inside the valve cover as it slowly drips back inside the engine via "drain back holes" inside the cylinder head, on a V-8 or V-6 engine, the valve covers are at an angle, and the oil accumulates at the bottom of the valve cover, and that . sludge build-up due to lack of frequent oil changes can cause these drain back holes to become restricted, slowing the drain back process and that this restriction causes the oil to accumulate in the valve cover longer and exert more pressure on the valve cover gaskets. If that's the case is there much remedy short of at least upper engine rebuild/overhaul?

Also, would a restricted PCV valve be a likely contributor maybe causing excess pressure under the valve covers and making the gaskets leak?

Does it ever do much good, for long anyway, to at least simply check the valve cover bolts for tightness and torque them down if they seem to have loosened? This engine apparently has about 138,000 miles on it. Time to just replace the valve cover gaskets because they're old, or not necessarily?

Any comments/advice appreciated.
 
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Old 05-13-12, 04:55 AM
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I'll throw out a "yes" to most of your questions except maybe the oil level:

1. No, extra half a quart probably not a factor.
2. Yes, clogged drain holes sometimes make the heads retain oil.
3. Yes, there is a remedy short of top-end overhaul - valve cover gaskets, as you talk about; probably no need to go further.
4. Restricted pcv causing excess pressure - maybe, but I think that's down the list of possibles.
5. Yes, always worth a shot to snug down the valve cover bolts; just don't over tighten and snap one off. Often snugging the bolts will stop a leak.

 
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Old 05-13-12, 07:44 AM
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if it leaks - replace it. you tighten those bolts - you'll make it worse.
as of the rest of the scientific stipulation - oil underneath valve cover is not under pressure. it simply squirts out of some openings, but has no pressure per se to be forced out, or bust the gasket. your coffee maker prolly has more pressure, and it does not leak, right?
you saw them hauling long haul cars on car carriers, with some almost vertical? where do you think that oil pools? and none of them leaks. modern engines are fully sealed, you could, possibly, haul them upside down.
when you replace gasket, make sure to put dabs of oil resistant silicone where gasket wraps around camshafts, unless yours is perfect flat.
 
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Old 05-13-12, 09:02 AM
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Okay, thanks for replies. In regard to my mention of possibility of clogged drain holes, the "remedy" I was asking about was how to go about getting them unclogged. As far as all the scientific stipulating about the oil underneath the valve cover possibly being under pressure, that came from article here: Oil Leak | Causes | How to Stop
 
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Old 05-13-12, 06:39 PM
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Seafoam in crank case for about 500 miles before oil change. As de-clogging medium.
 
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Old 05-13-12, 06:44 PM
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Read the article. Whatever.
And this:
It is extremely common to have oil seeps from a valve cover on just about every car with over 30,000 miles
is nice piece of baloney.
You ever had your finger against PCV valve tube? Do you realize, how little pressure is created? Oill will be darn right contaminated with exhaust byproducts, but to blow a gasket?
 
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Old 05-14-12, 04:45 AM
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Wow, every car over 30,000 miles leaks from valve cover gasket? Must have been written by someone who upsells that "repair" to pad their bottom line.

gull, you didn't mention how many miles on the beast.....
 
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Old 05-14-12, 08:02 AM
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Beast odomoter says almost 138,000 miles (mentioned in initial post here). Seafoam into crankcase then change oil after 500 miles sounds worth doing. Will go ahead now and replace the gaskets. Was mainly just curious about those other factors I read about that may supposedly contribute/cause the leakage/seepage from the gaskets, other than just expected wear from age and engine operation.

thanks for the replies.
 
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