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79 400m Valve Cover Leak

I have a 400m that i just cant get one valve cover to seal up. Its the driver side valve cover and it doesnt seal. The other side seals perfectly fine.. The valve covers are after market mr. gasket chrome ones. Could this be a warped head?? please help!! iv tried everthing!
 

LEB Ben

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If the head was warped, there'll be more problems than the VC not sealing. More likely is the VC is warped. Is there a general area in particular that's leaking??? Back of the block, front of the block, pooling by the intake, etc. Cork or rubber gaskets? Cork could have torn already. Tried double gaskets??? Sometimes if the VC gets torqued down too far too many times, the bolt holes start to distort, and can even tear.
 
Its leaking on the bottom side seems like the whole length of the head. Cork gasket should I try rubber? The vc is pretty new.. should I just use silicone no gasket?
 

LEB Ben

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The VC...and I'd venture a guess that most of us here have had this problem, and are relaying our fixes/finds.
 

Jolly Green

I Salt My Ketchup
Are you talking on the head or vc? Has anyone else ever had this problem?

The VC...and I'd venture a guess that most of us here have had this problem, and are relaying our fixes/finds.

I think you're right. I'm pretty sure valve cover leaks came as standard equimpment on 78/79 351M's and 400's.

You may just want to pull it off and make sure nothing shifted around or tore when you put it on. It can happen, no matter how careful you are. Hopefully, it's that simple for you.
 

fatherdoug

Tonto Papadapolous
A little bit of tightening on a regular basis will be much better then reefing on them when installed. You will either get to the point where they will stop leaking, or you will squish the gasket out and have to replace it. :headbang:

This is assuming the VC is not warped.
 
I took the valve cover off yesterday put a nice even bead of silicone all the way around the valve cover and around the bolt holes and let it sit over night before putting heat to it and come to find out today after driving it a few miles it still leaks!! I dont get it. Should i try a rubber gasket? Or should i just buy some more expensive valve covers that wont warp? i dont get it...
 

fatherdoug

Tonto Papadapolous
I think you will find out that another set of gaskets will give the same results. I would vote for replacing the valve covers. Is there any old gasket material still left on the head that is causing a "ridge", allowing oil to leak out?
 

LEB Ben

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I'd really like to see pics of these VC's on and off, a good bead of silicone fixes alot of sins.
 

bucks77ford

We will Rise Again
The aftermarket thin chrome valve covers can be a pain to get sealed. I have Ford racing chrome ones and I use a re-useable rubber gasket. So far I haven't had any problems.
 
I got the leak to stop... Stupid thing to fix it... The breather hose that goes to the air cleaner was pinched off and i put an elbow in there and got it so its open and would ya know it no more leak! simple fix
 

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