Valve Cover Leak

[dfrazz]

I have a valve cover leak on the back left side (closest to the firewall) of my Mopar 360. I replaced the gasket but did not notice any wear/tear. It was leaking again, even more severe, after the gaskets were replaced. I used rubber gaskets with black RTV. The covers have long spindle type bolts. I would appreciate any ideas on what next steps might be. Thanks.

 

[moparleo]

If you have the stock stamped covers you will need to straighten out the gasket flanges. Use gasket sealer on the covers only. Let it dry and just snug the valve cover bolts enough to seal. If you over tighten the valve cover bolts you just bed the gasket flange and it will leak. Are you putting any type of washer under the valve cover bolts ?

 

[dfrazz]

No washers on the bolts. I believe they are the stock black covers for a crate 360, with Mopar written on the sides. I did put sealer on both sides, so that could be part of the problem. I hand tightened the bolts but tried them after I noticed it leaking again and they were a little loose, so I thought maybe I need to really tighten them down. Is it recommended to do a heat cycle and then retighten?

 

[moparleo]

If they are the cast aluminum covers you should not be having any leak problems. With the covers off, check the gasket flange area for being straight with a straight edge. Also make sure you get the cylinder head where the gasket seals is totally clean of any possible old gasket or sealer material. Also tighten valve cover bolts in the same type of pattern as the head bolts. Each bolt a little at a time until they all tighten at the same time. One of the improvements on the magnum heads was to add 5 additional retaining bolts totaling 10. The old valve covers only had 5 total bolts. Otherwise it makes no sense to leak. Very straight forward install.

 

[dfrazz]

It has the old covers with 5 total bolts on each side. I checked and everything looks straight and clean. I'll try it again. Thanks for your help.

 

[moparleo]

Can you see it leaking or is it just oily at the back of the motor ? Use a mirror to check leak, also check the oil pressure sender at the back of the block. A common oil leak.

 

[moparleo]

stutter

 

[dfrazz]

Thanks, I will check the sender. The leak was noticeable above the #6 and 8 spark plugs, ran all the way down the block, covered the oil filter and was dripping off the oil pan. There was some blow back all the way down the tranny. I noticed a leak on the oil pan gasket too prior to this leak.

 

[Dfr360cuda]

Do you use a PCV
Do you have breathers
Blow by may be pushing oil out of valve covers

 

[Adam]

Several years ago I bought a new set of Mopar cast valve covers, unpainted. Both of the valve covers had small hairline cracks around one end which appeared to be a casting flaw. These cracks would not have been noticeable from the outside if they had been painted. Pull the cover and look closely for cracks.

 

[Chryco Psycho]

the heads are never flat so th ecast covers will not bend or conform to the head surface , if they are factory steel covers they seal better , oil sender is a good call as well

 

[dfrazz]

Thanks. I ended up replacing 2 sets of gaskets and a new pcv and pcv line and it finally stopped leaking.

 

[burdar]

Those cast aluminum valve covers usually require two gaskets per side. The mounting flange hits the intake and doesn't let the cover sit down onto the head properly.

 

[moper]

I will use 3M weatherstrip adhesive to glue the gaskets to the covers, or if needed glue one to the cover, and second on top of it, and then a think skin of RTV on the head side. No leaks. Even on multiple retorques due to mechanical cams.