Author Topic: Valve Cover Oil Leak  (Read 538 times)

Offline Travis Blake

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Valve Cover Oil Leak
« on: June 07, 2017 - 05:04:40 pm »
Back with the bane of my existence!!!

The passenger side valve cover WILL NOT STOP LEAKING!!! I�ve tried cork, rubber, and Carbon X gaskets with and without Permatex. It doesn�t look like the bolts are sucking down the valve cover all the way around. And it leaks like a SOB out of the back of the cover between the bolts.

It�s a stock, cast iron head with AMD covers

Are there any shims/spreaders that I can get to help suck it down?
1974 Dodge Challenger  - 440 Six Pack
2015 Jeep Wrangler Unlimited - Willy's Edition




Online Beekeeper

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Re: Valve Cover Oil Leak
« Reply #1 on: June 07, 2017 - 05:49:10 pm »
Have you tried screwing in the bolts without the cover to verify they are not bottoming out? I've had this happen with gunk at the bottom of the holes or I could also see it with bolts that are a thread or two too long.

Offline Racer57

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Re: Valve Cover Oil Leak
« Reply #2 on: June 07, 2017 - 06:29:10 pm »
I had a hard time with my 383 leaking really bad. I finally got some Moroso gaskets what have metal in the middle. I then used some Prep-Sol to remove all oil from the head and the valve cover. When the head was spotless, I used permatex high heat silicone on both sides of the gaskets and let them sit for about 15min before putting them on the cover and tightening down.  That was over 10,000 miles ago and no leaks.
« Last Edit: June 07, 2017 - 06:31:31 pm by Racer57 »


Offline tman

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Re: Valve Cover Oil Leak
« Reply #3 on: June 07, 2017 - 07:17:10 pm »
What are you using to bolt down vc?  Stock looking bolts with combination studs at the front and rear lower corners? 
I can tell you my issue that bugged me for a long time.  I had the stud on the right rear head.  Leaked there all the time.  Found out when using the nut on that lower corner, the shoulder of the stud was a hair too high.  So the vc was not making full contact there.  Got a new stud where the shoulder was lower. That solved my issue.
If you are using all bolts, then as mentioned above, are they bottoming out, thus bolts too long.
Its always that damn lower rear corners where they leak, especially the right side.

Offline Travis Blake

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Re: Valve Cover Oil Leak
« Reply #4 on: June 07, 2017 - 09:32:18 pm »
Hi guys,

Using a valve cover bolt kit from AMD. You can see the impression in the gasket from the bolt when you take the off, so I'm fairly certain its not bottoming out.

I've tried the Moroso gaskets and it was still leaking. Is stacking gaskets a thing? For instance, stacking the moroso's on top of the Carbon X's? Each gasket kind of serves a different purpose. The carbons are so thick they make up for any inconsistency in the level of the head, and the moroso's metal distribute the load. Would the two combined with some silicone help?
1974 Dodge Challenger  - 440 Six Pack
2015 Jeep Wrangler Unlimited - Willy's Edition

Offline cudabob496

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Re: Valve Cover Oil Leak
« Reply #5 on: June 07, 2017 - 11:38:50 pm »
remove high spots

clean real good both surfaces

turn valve cover upside down.
lay bead of RTV on cover
place gasket
lay bead of RTV on gasket or head seating surface
place valve cover on engine, and tighten down half way
let sit for 3 hrs
tighten down all the way
don't run engine for 24 hrs

this is the only method that has worked for me, as surfaces are not perfectly
flat on my covers.
I use the gaskets from Moroso
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.
Up to 4000 RPM, Warp Speed, Up to 5000, Rediculous Speed, Up to 6000 RPM, Ludicrous Speed!

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

Offline tman

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Re: Valve Cover Oil Leak
« Reply #6 on: June 08, 2017 - 02:19:34 am »
Can you see the impression on the gasket that contacts the head?

Offline 72hemi

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1972 Dodge Challenger 340 6 Pack 4-speed
1996 Dodge Viper GTS Coupe

Offline 73_Cuda_4_Me

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Re: Valve Cover Oil Leak
« Reply #8 on: June 08, 2017 - 08:54:16 am »
Trial-fit valve cover on head without gasket, and look for interference of lip on valve cover with intake manifold...

If heads have been milled or block has been decked, and intake has not been, it can sit higher on intake side of heads, causing interference with valve cover lip...

Don't ask me how I know this... LOL
1973 Plymouth Cuda BS23H3B567783

R11 V6X EN2
M21 M25 M31 M88 N41 N42
V1X U B41 C56 G37 J54
JY9 A6X9 0 703 501616
E55 D34 BS23 H3B 567783

Offline jason340

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Re: Valve Cover Oil Leak
« Reply #9 on: June 08, 2017 - 10:00:22 am »
Have you taken a real close look at the valve covers as there could be a small crack at the mating surface that opens up when tightened down. Just a thought.

When you remove the valve covers has the old gasket stayed in place from the last assembly?  Mine poured oil one time and when I took the vc off I found the gasket had moved on the last assembly and was not even touching the head between the bolts. I then used contact cement on the valve cover side, let it set up and then used a thin coating of Permatex copper on the head side and no leak, cork gaskets. I do have aluminum  valve covers.

Offline Travis Blake

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Re: Valve Cover Oil Leak
« Reply #10 on: June 09, 2017 - 10:17:01 am »
Hey gang,

IT'S FIXED!!! For now at least. As per usual, thank you for all of the advice and insight. What did we do before the internet?

1974 Dodge Challenger  - 440 Six Pack
2015 Jeep Wrangler Unlimited - Willy's Edition

Offline tman

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Re: Valve Cover Oil Leak
« Reply #11 on: June 09, 2017 - 11:30:16 am »
Please share your experience.  It helps others. 

Offline polarbear123

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Re: Valve Cover Oil Leak
« Reply #12 on: June 09, 2017 - 01:33:19 pm »
 :iagree:

tell us how

Offline chargerdon

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Re: Valve Cover Oil Leak
« Reply #13 on: June 09, 2017 - 01:43:10 pm »
I had a leaking problem on my 383 using Edlebrock chromed valve covers.   I tried everything but NEVER got them to seal on the passenger sides.   I have the big block HP exhaust manifold which made it difficult to get the gasket on straignt and stay there.   Got ticked and put on the stock original valve covers and no leak.

Issue with the Edlebrock chromed covers (which looked great) was that the gasket wouldn't stay in place when tightening down the bolts.  I had tried everything but the gasket would slide off of those chromed covers.   RTV didnt stick real good to the chrome either.. 

Offline Travis Blake

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Re: Valve Cover Oil Leak
« Reply #14 on: June 09, 2017 - 09:08:54 pm »
Sure thing. Sorry bout that.

Worked with a shop near me. The owner has been racing for a long time, and is very familiar with mopars. We took a bead of permatex in the lip of the cover, seated the carbon X gasket in place and it sat overnight. You can see the indentation from the head on the gasket EXCEPT in the one spot where it was pouring out the back. So it wasnt making contact there. So we seated the cover on the head, and put the bolts in with a set of the tabs show in the image. And it disbursed the pressure enough to seal evenly.

I drove it for four hours straight (the joy of no burning oil kept me on the road) and the back of the head, and exhaust pipe were bone dry! I believe that these tabs are GM/Ford specific. I've never noticed them on a mopar before, though I may have just missed them. But they work SO well.

As we all know there is never a silver bullet fix for any one given problem. So I encourage anyone with a still leaking valve cover to try these. I have been fighting this for about a year an a half, and it a GM part works, then so be it!
« Last Edit: June 09, 2017 - 09:14:35 pm by Travis Blake »
1974 Dodge Challenger  - 440 Six Pack
2015 Jeep Wrangler Unlimited - Willy's Edition