Hemi heads leak oil?

[PRO]

Anybody with any Hemi experience ever seen a 426 Hemi leak oil from the heads?,its coming from between the Head and the block at the Head gasket only along the rear,the portion which faces the firewall,Im positive its not the valve cover,(this portion of the head overhags the block by .5")or the intake gasket or the sending unit,its leaking on the front and back of 1 head and the back of the other.Its just been rebuilt supposedly and has MP cast iron heads on a 67 block,it definately looks to have been rebuilt,any input is appreciated.Im just looking for input before I pull the heads thanks...............PRO..........

[vanishPt]

a quite common thing.

[DartGT66]

Maybe it has something to do with the head oil return passages?

[Crank]

Pro are you sure it's not the manifold? crank case presure.

[BelvedereGuy]

I would be checking the mating surface where the head, block and intake meet up. Silicone is supposed to be put there to aid in sealing....but if it wasn't done right you will have problems for sure. The only other problem I have heard of is that it is sometimes difficult to also get the valve cover to seal right or the gasket is not in properly. An old trick for that problem was to glue the new gasket to the valve cover using weatherstip adhesive and then put it on a clean bench and cover with a towel and then add a little bit of weight...making sure the gasket is in place properly. After a couple hours the glue will be dry and the covers will be ready to install......you should no longer have any problems with the valve covers.....and the adhesive has just eliminated another surface for a leak to come through.
I highly doubt the oil is coming from between the block and the cylinder head.........and would almost be willing to bet it is coming from an incorrectly sealed intake or valve cover. I would start with the process or elimination and replace the intake and the valve cover gaskets first(cheaper and easier also). Make sure you clean everything real good afterwords when the silicone has dried, that way if you do encounter another leak it will be easier to determine where it is coming from. I like to use Brakeclean for degreasing that kind of situation....it comes in a can like WD40 and even has a tube for getting the spray just where you want it.
I hope this will help.

[Best Machine]

Pro
If the mopar performance valve cover gaskets were used, Replace them they were made wronge.One of the corner bolt holes is in the wronge spot. You can strech the gasket over the studs but it changes the shape and the cover will not compress the gasket completly. Mopar has pulled the gaskets from invertory but it has only been a few weeks im sure there is a lot out there still. Use the fel pro, its a little thinner but it will seal.

www.BestMachineRacing.com

[PRO]

It leaks as if its the return passages there doesnt seem to be any pressure behind it,Im positive its not the intake or valve covers as I have it on the lift and its spotless everywhere,with it idling and Im underneath it watching it leak it comes right out between the head and block,remember the head actually overhangs the block on a hemi,the intake gasket at the ends are both bone dry,it only leaks at the bottom corners of the head,any more thoughts?............PRO.......

[BelvedereGuy]

The bottom corners near the exhaust side of the head are indeed where the oil drain backs are located....one front, one rear. It does sound like you will have to pull the heads, at least for a head gasket change. Before removing the head you should check the torque of the head bolts as they may not have been torqued right and this led to your problem starting. Once the heads are off and the surfaces are clean, you are going to have to check the block and head surface to make sure they are true and then take the appropriate action to solve any problems you may have with a warped head or block surface. I find it odd that both heads would start leaking at the same time. Was the right head gasket used for the right cylinder head material? It is possible the wrong head gaskets were used. Were the heads torqued properly and in the right order? This could also lead to gasket failure. Once the gaskets start leaking, there is not much you can do to stop it, other than replaceing them.
This is just my experience working with other motors, and at one time I was an engine machinist, so I do have some experience working with the problem you are describing.
I own a Hemi (472)as well, but right now it is just sitting on the stand on the floor as I just recieved it from Chrysler and my car is nowhere near ready to have it installed into.
Let me know what happens and what you figure out. This is only my opinion and others may have better ideas, but what I described above is what I would be getting ready to do.

[vanishPt]

Still think that it is common. I fixed mine by spraying brake clean where I could see the oil. Then I took some Ultra Copper (same color as the block) and smeared on the that area. Has not leaked since.

[jkailholz@aol.com]

Oh you better get rid of that engine real soon! sounds like your in real trouble. Of course I'll help you out and take it off your hands. hehehe. Hope you get it fixed and it doesn't cost you too much.

[23T-Wedge]

Pro,

One other possibility to check if you take the heads off, make sure the dowel pins are not bottoming out in the hole, check the dowel holes for silicone or gasket sealer buildup that might be keeping the head from torquing down completely on the corners.
Just something else to look for.............

[Lee Pritchard]

I have had that happen a few times.... if you are using the factory steel head gasket you need to use K&W copper coat on the gaskets and the problem will stop...Lee...

[PRO]

Just thought Id update everyone with what I found,by the way thanks for all your input,as many of you know there are five rocker stands per side,3 non oilers and 2 are oilers,when assembled it should go,non oiler,oiler,non oiler,oiler,non oiler if you get it wrong on the end of the heads(oiler where a non should be)it will leak out past the head gasket especially with a steel shim type,so needless to say since whoever put this together didnt have a clue I have disassembled the whole motor and am checking everything.........PRO.....

[BelvedereGuy]

Well that's very interesting. I guess your lucky it did leak......could you imagine if it didn't.....the thought is scarry.
I think you are doing the right thing now by taking the motor down and checking everything....better to be safe than sorry.
Thanks for updating us and I hope you have better luck with it in the future.