Valve cover leak has defeated me for 10 years, need help!

[AKcharger]

Since I put the engine together on the '72 I have ALWAYS had an oil leak from the valve covers, mostly the PAX side. I admit complete defeat!  I'm now thinking it's not a valve cover issue but a head issue, any suggestions appreciated:

2010 - engine rebuilt w/440 source cheater heads and stock valve covers always slight leak pax side
- replaced cork gaskets and resealed...still leaked
- tried hard rubber gaskets leaked
- replaced valve covers completely with new stampings figuring old covers were "warped" nope leaked
- Used "leak-proof" 50145 gaskets, same leak
- Installed studs for a easier flatter Installation no change
- latest attempt NOS M/T covers as these were nice and ridged...HORRIBLE, leaked a pint of oil in 5 min from pax side

Each time all old sealant is removed, to nice clean metal and I solvent the surface to ensure sealant adhesion.

I'm thinking the valve cover is hitting the top of the rocker shift and not letting it seat properly. Would explain why the M/T poured out oil cause it wouldn't flex at all where factory one would give a bit

[1970Moparmann]

Wow, you have tried a lot of crap... LOL. 

I have had the same problem with my Coronet.  I just bought cork again and used this and it seemed to clear up the issue for me.   

https://www.amazon.com/Permatex-80019-Aviation-Gasket-Sealant/dp/B000HBM3QQ/ref=asc_df_B000HBM3QQ?tag=bingshoppinga-20&linkCode=df0&hvadid=80401840125115&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584001418869333&psc=1

[AKcharger]

I'll try anything, thanks!

[b5blue]

I found some screws were too long for my Sidewinder heads. You tighten down but the cover isn't snug. I'm also using rubber with steel core gaskets, supposed to be reusable. 

[1970Moparmann]

I found a thread to do the following -

Put the Form-a-Gasket on one side, wait an hour, then put on the other.   Put on the valve covers on the car and just had tighten.  Wait a night, then torque down.     Seemed to work for me. 

[Kern Dog]

This stuff is the best sealant that I have ever used.

[b5blue]

Gaskets I bought, reusable: https://www.ebay.com/itm/333884250943?hash=item4dbd0d5b3f:g:GpwAAOSwCyBhZbWC

[birdsandbees]

Cheap cork gaskets, no sealant, no leaks. Thought I'd buy the "better" gaskets and they leak on OE cast heads, even with sealant.

[AKcharger]

Good tips Thanks!
- B5 yeah thought of that thats why I went with studs in the heads, same leaks. So those reusable ones, no sealant?
- 1970 mopar - are you putting that stuff on gasket or head/cover surfaces?
- B&B I've always had good luck with that too...on cast iron heads, I think thats the trick
- copy kern dog, will try

[b5blue]

I've got Cal Custom VC's and seal the gasket to just the cover. Light film of grease on the gasket to head surface. 

[Just 6T9 CHGR]

Ehrenberg sells these exh manifold gaskets to prevent the pass side from burning...specially with HP manifolds the pass side is super close to the VC.
I have my manifolds Jet-Hot coated and it still burns the paint slightly on the pass VC

https://www.ebay.com/itm/324747602039?hash=item4b9c772877:g:9uUAAOSwiMRbCaa6

[AKcharger]

I've got Cal Custom VC's and seal the gasket to just the cover. Light film of grease on the gasket to head surface. 

- Wait,  so you're not sealing the gasket to the head? And use grease??
- thx 6t9, like those gaskets!!! However with mine the leak starts usually within minutes, last one has oil smoke 3 minutes after starting

I called 440 source to see if they heard of anyone else having g issues...nope, I'm the only one

[b5blue]

Trick learned from a 60's mechanic, glue/seal to cover and light film of grease to gasket allows it to form to head or other surface for sealing. (Like timing chain cover.) Remember I'm using rubber gaskets.

[AKcharger]

Thanks b5, I'll try that when I get home. Heck my only option is just keep throwing diffrent gaskets/sealants at it till someday ii hope it stops.

[b5blue]

Re check the heads with a straight edge and look for casting defects. 

[metallicareload99]

I found a thread to do the following -

Put the Form-a-Gasket on one side, wait an hour, then put on the other.   Put on the valve covers on the car and just had tighten.  Wait a night, then torque down.     Seemed to work for me. 

I can't remember if the 440 source heads have the rail milled flat or is it as cast like stock? Def make sure your bolts aren't too long.

I used to use the Ultra Copper on everything, with less than great results. I'm starting to come around to some sealants are better than others for different jobs. I.E. the regular black seems to work better on valve covers than the high temp stuff. The "Right Stuff" seems to work real good, but taking things apart after and cleaning it up could be a challenge.

At any rate I've had the best luck using the above method more or less. "Glue" the gasket to the valve cover with the sealant, wait 15 or so, use the sealant on the bottom of the valve cover. Set valvecover on engine, tighten bolts until they just start to compress, let it sit over night and then snug 'em up the next day. Snug up again after the first run. FWIW the RTV is "supposed" to need 24 hours before it's ready  75% of the time it works 100% of the time

[b5blue]

If you glue both sides how are you going to ever remove later? 

[metallicareload99]

If you glue both sides how are you going to ever remove later? 

Valid point. I was assuming a hydraulic cam scenario, where I've gone years without needing to remove a valve cover.

Now that I have a solid roller cam, I constantly have the valve cover on and off, checking lash every several hundred miles. Now I just use the Moroso steel cored blue gaskets on Trick Flow heads (valve cover rail milled flat) with Summit cast aluminum valve covers. Just wipe excess oil up, no sealant and no leaks

[Kern Dog]

Now that I have a solid roller cam, I constantly have the valve cover on and off, checking lash every several hundred miles. Now I just use the Moroso steel cored blue gaskets on Trick Flow heads (valve cover rail milled flat) with Summit cast aluminum valve covers. Just wipe excess oil up, no sealant and no leaks

You have something wrong if you have to adjust the lash that often.

[metallicareload99]

Now that I have a solid roller cam, I constantly have the valve cover on and off, checking lash every several hundred miles. Now I just use the Moroso steel cored blue gaskets on Trick Flow heads (valve cover rail milled flat) with Summit cast aluminum valve covers. Just wipe excess oil up, no sealant and no leaks

You have something wrong if you have to adjust the lash that often.

Checking... I do almost no actual adjusting

[AKcharger]

OK so I pulled the cover off the pax side, do these photos give any clue to the issue?  The cover came off easy enough with the gasket still sealed to the head. can you guys see anything suspicious??

[metallicareload99]

Looks like everything is lining up OK. No RTV on the valve cover side? Using stamped steel covers? Those gaskets worked ok for me, but if you only wanted to RTV one side I'd do the valve cover side tho

[b5blue]

The corner areas look like the gasket swings out too wide. (?)

[AKcharger]

OK next plan of attack is:
- Right stuff sealant and do gasket to valve cover, 12 hour cure and seal head to valve cover gasket with 12 hour cure run and retighten
- Trying same fel pro gaskets

have to leave tomorrow for another 5 day trip so will be next week till I have a report

The corner areas look like the gasket swings out too wide. (?)

can you show where you mean??

[Nacho-RT74]

MaMopar didn't use exhaust to heads gasket. They aren't even listed into the parts catalog... and even aftermarket kits include those, I decided to keep MaMopar decision for this. Just a light coat of hiTemp Sealant, which even it will burn, is able to keep any small Hole ( of some due rust ) filled. So far so good never have got an exhauts leak there.

Now... Manifold to Pipes... that's another deal and it has been a HUGE headache for me along the years LOL.

About valve cover oil leak... are you sure is the head valve cover edge and not a tiny crack on head ?

BTW, I use the sealant just on valve cover side, never on head side. I think last time I even use contact cement instead silicone sealant!! Stock valve covers

[Kern Dog]

I have the cast aluminum Mopar Performance valve covers and Edelbrock heads.  I have had this setup since 2004.
Gravity being what it is, I never saw any leaks near the top of the VCs. The leaks I'd see were always along the bottom and rear edges. The Edelbrock heads have a machined gasket rail. I don't know if that helps or hinders a good seal.
Aside from the "Right Stuff", I stumbled upon something else that helped.....
The mounting holes in the valve covers are loose enough that the VCs can actually slide around a bit before the bolts are tight. In my case, just resting the VC on the head THEN tightening the bolts often resulted in an offset of the gasket and head. Tightening the bolts sometimes deformed the gasket and induced a leak.
I found that this worked: I put a thin layer of The Right Stuff on the valve cover, then lay down any one of the black fiber gaskets. Let it sit about 1/2 hour. This stuff sets up quick.  Rest the VC on the head, then push the VC up toward the carburetor and tighten the bolts. This made the bottom rail line up with the valve cover and gasket.

[b5blue]

With my milled edge Sidewinders and Cal Custom VC's it took awhile to figure out the holes are a bit shorter for compression of the gasket. I'm using the rubber gaskets with steel reinforced centers as they hold their shape and are a bit thicker. 

[AKcharger]

- Nacho - I am completely out of answers on this. I NEVER had an issue on any cast Iron heads, only this engine and the aluminum heads is the only discriminator
- Kerndog - I'm going to follow your lead with the sealant. if I do gasket to cover and Gasket to head it SHOULD work..we'll see
- B5 blue - the M/T's are the last gasp, if they don't work I don't know what to do. If next try doesn't work I'm trying you "seal cover/grease head" method

I've been cleaning all the oil out of the head, I think that MIGHT help. figure perhaps the rail is a little oily and sealant isn't "grabbing"

[b5blue]

   If ya try my way clean all that silicone off of everything and I use the same stuff as corney used but in a toothpaste type tube. Seal the rubber gasket to the VC and lay it on a flat surface till dry. A very light film of grease on the gasket allows it to seat under compression. (The grease is not sealing, it allows slight shifting.)

[AKcharger]

OK, gasket is sealed to Valve cover. I did note the hard gasket was mis-align with the cover unless it was forcibly positioned, so this would account for the massive leak. I have it curing up tonight and will try B5's grease method tomorrow

[AKcharger]

OK, update!
B5's sealant on top and grease on bottom seems to be working. I did the pax side and ran it for about 15 min. There was an ever so slight bit of smoke but I think that's the oil from previous leak burning off. Now doing Drivers side cover...I'm hopeful!

[AKcharger]

Final update - still leaks 
Good news its not as bad, but still there on pax side. I cleaned it let it run/burn off and if I drive at higher RPMS I can open the hood and see a few drops smoking on the manifold, but not the cloud it used to be so I'll call it good and accept defeat
Drivers is holding well.
Thanks for the tips!

[b5blue]

Did you check the gasket to head shape? (Lay the gasket on the head and align screw holes.) 

[AKcharger]

Did you check the gasket to head shape? (Lay the gasket on the head and align screw holes.) 

Well if mean lay gasket on head and does it look right...yes

I can't figure it out...and I'm super smart! I've never ran into this problem on any other vehicle in my life.
- 3 sets of valve covers
- 8 sets of gaskets from cork to composite
- valve cover bolts
- valve cover studs
- 4 diffrent types of sealant
- no sealant


I can only assume it's the head casting by 440 source, only variable left but im not pulling them off for a leak

[b5blue]

Look under the intake. You can have oil work it's way up and on to the pan. In the rear it can just make it out next to the valve cover. 

[Mike1268]

I use cork and "Permatex Aviation Gasket Sealer" on both sides of the gasket.  Never had a problem.

[AKcharger]

Well, it's still leakin, I'll try anything, thanks!

[b5blue]

I noticed using Mopar brand valve cover (black) bolts on Sidewinder heads and Cal Custom (vintage) covers with the black rubber steel reinforced gaskets were just a bit long. It stopped proper tightening just a bit. (Really pissed me off but don't know who to blame.  ) 

[AKcharger]

Still leaking BTW, 12 years now, even had a shop try 2 times, they had no better luck

[LaOtto70Charger]

That sounds like my transmission leak I have been missing with for 20 years

[Dino]

The edges on the heads are narrow and rough. It makes it almost impossible to get a proper seal. I thought about cutting a groove into the seals so they would slip over the edge a bit.

[AKcharger]

Thanks Dino, I'm gonna give it one more try and say "F it" and swap out the heads...its the only variable there is. As soon as I'm done battling my EFI demons I saw a trick about pumping air in the block to fi d the exact location of the leak.

[4cruzin]

Some good ideas here . . fighting this same problem now.   

[will]

I would put rtv all the way around the bolt holes. Otherwise BTDT.

[AKcharger]

Ok EFI battle won, now to tackle this. Suggested method is use weather strip to seal gasket to cover, cure 24 hours then use black gasket maker and seal to head tighten a bit...24 hours then tighten fully
 

[b5blue]

Check bolt length carefully. 

[AKcharger]

OK lets see how this goes...gasket sealed to cover with weather strip sealer, head is SPOTLESS and black gasket maker applied. I'll let it sit 36 hours to cure. Finger crossed

[b5blue]

I used black rubber gaskets with steel cores. 

[Kern Dog]

The black fibrous gaskets don't deform like the softer designs. I used to use cork and seemed to have good luck with them but only if they were coated with RTV and let to set up before installing.
Sorry if I have already mentioned this here but the one thing that made all the difference for me was not just the gaskets themselves but the positioning of the valve cover.
The mounting holes allow a degree of movement that can result in a misalignment from the valve cover to the head. If the covers are allowed to slip down away from the intake and toward the exhaust, the bottom flanges of both the head and VC are offset, Gravity being what it is, this increases the chance of a leak. I've found that I need to pull the VC up toward the intake before tightening down the bolts. Maybe my mounting holes are off center slightly but this reduced my leaks by a huge margin. I've done this on other engines and it seems to have helped there too.

[John_Kunkel]

For several decades, the factory has used no gaskets on some installations with stamped metal covers. On problem leaks, instead of a gasket, one might try a really thick bead of RTV allowed to skin over before installation and only tightening the bolts enough to compress the bead. Allow to sit overnight before running.

[Kern Dog]

NO gaskets?
Which engines were built this way? That would be a strange practice.

[AKcharger]

So far so good, but will take a bit to be sure, it usually is good and starts leaking after about 2 hours of operation.

[John_Kunkel]

NO gaskets?
Which engines were built this way? That would be a strange practice.

I didn't say "engines" in particular, I said "installations". Such things as rear end covers have used only sealant for decades.

[Kern Dog]

The inference was engines since this thread is about valve covers.
I thought that maybe there was some application that I didn't know about. I'm always anxious to learn new things.

[b5blue]

hear or heard? 

[AKcharger]

I did notice the bolts (chrome tie downs) were loose after every run. might need safety wire

[AKcharger]

Ever so slight leak now, but bolts were again loose. This might have been cause all along. interestingly ONLY the pax sides are loose NOT the drivers side??

Anyway, safety wire in place which SHOULD cure it but now battling an EFI issue again so long test drive will have to wait 

[AKcharger]

Oh! Oh! I think I might have it!! Carb is back on and took car for a good 1/2 hour ride today. at stop light on occasion I would get a quick whiff of oil but upon arriving home nothing, even exhaust pipe (where oil would drip) is dry as a bone!

My new theory is this...it IS the heads. When they were made the Chinese miss-drilled the valve cover holes where they were a tad too big and allowed oll the bolts to loose. IKR SHOCKER! a Chinese made part substandard!? 2008 440 source heads

[b5blue]

 

[cdr]

NO gaskets?
Which engines were built this way? That would be a strange practice.

In the late 70's to about the mid 80's EVERY dang small block Chevy used orange silicon in place of valve cover gaskets, & they leaked lol.

[Derwud]

What Cam are you running and have you checked your PCV?