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  • September 30, 2022, 12:31:26 PM

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Author Topic: Valve cover oil leak  (Read 2208 times)

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Offline acecarbo

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Valve cover oil leak
« on: April 08, 2020, 02:52:08 PM »
Hello, I own a 1983 Eagle Wagon that I purchased 4 months ago.  It had the original plastic valve cover that leaked. I replaced it with a "new and improved" made to fix the problem plastic valve cover. Well, after driving it for a month I still have a leak. Is there any sure fire ways to fix this problem? I will also add that I used the gasket that came with the new one that was a piece of metal sandwiched between rubber and that leaked just as bad, so I put in an old school cork gasket that slowed it down but did not fix it completely. Thanx for any additional help. Mike

Online rmick

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Re: Valve cover oil leak
« Reply #1 on: April 08, 2020, 05:33:34 PM »
You will want to change out to an aluminum valve cover for a 258 for that year. Search for  Jeep 258 valve coverer you year eagle.https://www.morris4x4center.com/valve-cover-aluminum-matte-kit-83501398-al.html
72 Javelin AMX
72 Javelin SST
72 Gremlin with 4.0
81 SX 4

Offline Taylor

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Re: Valve cover oil leak
« Reply #2 on: April 09, 2020, 07:48:49 AM »
Morris is a good place to get it, good service. Definitely go with a aluminum cover.
2010 Toyota Rav4 Sometimes Commuter (better mileage and family beater)
1985 AMC Eagle Limited Wagon 🖖🏼🦅 Eats Audi quatros for breakfast😎 Official Member of the Land Rover recovery team.
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Online MIPS

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Re: Valve cover oil leak
« Reply #3 on: May 06, 2020, 12:56:19 AM »
Same. Grab an aluminum valve cover and a good cork/rubber cover gasket.

I've had really good success in putting a bead of RTV on the head's gasket surface and on the new valve cover mating surfaces. Assemble, finger tighten all bolts and leave for several hours to initially set, then torque the valve cover bolts to 10 foot pounds.

Offline AMC1

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Re: Valve cover oil leak
« Reply #4 on: May 06, 2020, 11:33:17 AM »
I'm sure everyone hopes an aluminum cover will solve your problem but what concerned me is that even with a new plastic one you are still leaking. When you take it off put a straight edge on you cylinder head and see if can see any light. You may have a warped head. You should also be torqueing it down to 84 inch pounds - 7 ft lbs and no more - plastic or aluminum. In my opinion only - that is one of the key parts that you want to use a torque wrench on.
1976 gremlin
pair of 1983 SX4's sports
1946 Cushman step-thru

Offline AMC1

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Re: Valve cover oil leak
« Reply #5 on: May 10, 2020, 10:15:45 AM »
I'm going to retract my statement of using 84 in lbs. on a new gasket installation. That is actually an "in use" torque setting that I use. Even that might seem high since the TSM recommends 28 in lbs. for a new installation and not much more than that for "in use". I myself prefer more than the 28 but more importantly is to make all 9 the same. I'm sure you found out the rear one was the most difficult.
1976 gremlin
pair of 1983 SX4's sports
1946 Cushman step-thru

Offline charlie D

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Re: Valve cover oil leak
« Reply #6 on: September 23, 2020, 10:19:05 AM »
I am also new to the Eagle which I have had since April of this year. Mine has a valve cover oil leak that must have been going on for a long time as the block is pretty well coated with crud. I ordered an aluminum valve cover to replace the plastic one, but am thinking to try double cork gasket before the switch. I have a Triumph TR8 which are famous for valve cover leaks and one of the "cures" has been to simply double the gaskets to allow the gasket material to make up for any warps. Fellow TR8 owners who have tried loading up the RTV have not been successful. Has anyone on this forum found the double gasket approach to work with these plastic valve covers?
Charlie D

Offline Canoe

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Re: Valve cover oil leak
« Reply #7 on: September 24, 2020, 12:15:32 PM »
... valve cover oil leak that must have been going on for a long time ... I ordered an aluminum valve cover to replace the plastic one, but am thinking to try double cork gasket before the switch. ... Has anyone on this forum found the double gasket approach to work with these plastic valve covers?
258 leaking plastic valve covers are so much of an issue that manufacturers were (still are?) making double thick cork gaskets, so you don't have to use two regular thickness gaskets together. RTV on upper & lower sides of gasket, thick or thin depending on who you talked to. Worked on mine - for a while. I gave up and made my own steel cover.

Will it work for yours? Depends on how badly warped your cover, and if there is any damage to the groves along the sealing edge (famous for bits of those to break off) or to the ledge that the discs to clamp down on. If it's not too far gone now, it's just going to be getting heated, more brittle and further degrade.

A more extreme solution, is to get a 4.0 head with its aluminum valve cover. Can use the stock 258 intake manifold, but needs a different exhaust manifold, typically 4.0 headers. I think this is covered in the Eaglepedia under upgrades. Then with a 4.0 head, the engine can benefit from a different cam. Slippery slope on upgrades...

Offline Freeagle

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Re: Valve cover oil leak
« Reply #8 on: January 02, 2022, 03:14:42 AM »
I've found that using a gasket on the valve cover only promotes warping and cracking of the valve cover, making it leak worse. The thicker the gasket, the more can compress unevenly and warp or crack the cover. By far the best way I have found to seal the valve cover is to do it the way AMC originally did it: without any gasket at all.

AMC did extensive testing of the new plastic valve cover for leaks and durability before they put it into production, and they published an SAE technical journal paper about it. I've read the paper. AMC used NO GASKET. Instead, they literally pasted the valve cover onto the head with a special sealant developed with DuPont. I think Permatex "Right Stuff" is the same or very similar. 

Just clean your valve cover extremely well. I mean degrease the heck out of it. Same with the head. The surfaces must be perfectly grease and oil free. Lay a 1/4-inch bead of Right Stuff around the cover (maybe some on the head if needed) and place it straight down on the head. Tighten the bolts to specification while the sealant is still gooey. Leave it to cure for several days before you run the engine or get oil in contact with the sealant. Make sure the bolts stay snug from there on out and you will be leak-free.

I have 100% leak free valve covers from doing this.
1984 Eagle Limited Wagon

 

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