leaking valve covers?

[Mgicm]

Have a 48 suburban with a monte carlo 305 in it. seems i am seeing a large oil puddle under it after running it in place for a bit. Traced it up to the passenger side of vehicle. looks like oil dripping where corner of valve cover is near the exhaust manifold to pipe junction and down over the starter. i put on a new set of covers - steel - and the gasket is new already. Still seeing some smoke when it idles...from the same spot.

What would next steps be? Check the covers for flatness? add a second gasket? Tighten bolts? Right now they are just snug for fear of doing more harm than good. Didnt use any silicone..should I? Looking for some tips.

thanks

[capnduane]

My 55 2nd has a Pontiac 400, but valve covers are similar. I put on a set of chrome steel covers with black rubber gaskets. They started leaking in a few months. Recently got a set of aluminum covers and used the cork/rubber gaskets and no leaks. The chrome covers were thin and cheap, the aluminum covers are much more rigid and composite gaskets seem much better quality.

[mr48chev]

Steel covers do not take well to being over tightened. The longer hold down tabs do help and you can usually find them at the local parts house https://www.summitracing.com/search/...hold-down-tabs

I've got a pair of Tall Chevy performance chrome valve covers that I would give to someone's kid to make valve cover racers out of. I tried everything and could never keep them from leaking. I finally put on a pair of fabricated aluminum valve covers and the good reinforced Felpro gaskets and that got the job done. I think I use these the last go around, not cheap but they seem to work. https://www.summitracing.com/parts/fel-1644/overview/

[Mgicm]

where did you get the aluminum covers?

Did you use any silicone?

thanks

[dsraven]

also look for casting flaws in that area.
felpro makes a nice silicone gasket set that usually, along with a good flat cover surface and a set of those long load spreading bars under the bolts, will stop any oil leaks

[Indian113]

I have seen some people Over Tighten the hold down bolts. I sprayed a contact cement on the gasket then stuck it to " Those Cheap Steel Valve Covers" I also used the long hold down bars and Allen Bolts. I then just snugged the bolts and rechecked them every time I drove it after that. I also used a Cork Gasket I don't have any leakage after 3 years of driving.

[Mgicm]

how tight you making the bolts..? finger tight..? with a ratchet?

thanks

[Indian113]

I used Allen Head Bolts and used a T Handle Allen Wrench, I just snugged them down and tried to make it a even snug. I really think having a flat surface and good gaskets with the Long Hold Downs is important. If I remember right I first ran the bolt down flush, then criss crossing them I snugged a 1/4 turn on each bolt until it was tight.

[Hampshire]

X2 on dsraven solution. I would put my money on doing exactly that.

Only other possibility in that area is probably a long shot - in some sbcs the oil pressure line is tapped in near the distributor. A leak there looks just like one at lower back end of a VC.

[capnduane]

Just heard about this today from one of my club members. "Right stuff" by Permatex. No gasket, just a bead of this stuff and good to go. Might be worth a try? For sale on ebay.

[Jesse Z]

Originally Posted by Mgicm

Tighten bolts? Right now they are just snug for fear of doing more harm than good.

They're just snug and they leak? Duh, tighten them more ;-)

I used to be afraid of over-tightening steel valve cover bolts until a professional engine builder showed me how tight he made them - MUCH tighter than I had been. Now I never have leaks.

Hey, it's already leaking; what's the worst that can happen if you over-tighten? It just might cure your problem.

[OrrieG]

Old school trick on steel valve covers was to dimple the head side with a ball peen hammer so the holes are concave. Over time tightening them push the area around the holes out keeping them from sealing all the way. Same with steel oil pans and timing covers.

[crossfire84]

this mite help.

[dsraven]

personally I like to install some studs and then use nuts to tighten down the cover. some long T nuts work well but they don't have to be long. that way there is no threat of breaking a bolt off in the head or stripping the threads in the head. you can use the long connecting nuts from all thread to bring the nuts a bit away from the cover so easier to get the socket on them.

[62lwbc10]

Been through this many times. Scrupulously clean valve cover mating surface, ensure they are nice and flat. Lay on generous bead of weatherstripping adhesive aka gorilla snot. Lay high quality gaskets e.g. Felpro on top of the bead of adhesive. Lay covers gasket side down on a flat surface and allow to dry a couple hours. Install, use spreaders and down over tighten. Check tightness once in a while. Never leak again. Gluing the gaskets to the covers is the key.