Smoking Engine Block

Valve cover bolts should not be over tightened. As it leads to deforming the sealing lip, as well as broken bolts. Even grade 8 1/4-20 thread bolts will not handle high amounts of torque.

As for gaskets being changed 3 years ago, that doesn't mean much. They could have cracked, split, or could even be cheep ones. So take the valve covers off and change the gaskets, use good ones from Fel-Pro or MR.Gasket. Make sure the sealing lip on the valve cover is straight, not warped.

Exhaust manifolds are not oil cooled. If you have oil burning on them, it is coming from under them, or above them. If you have oil in them, you have internal engine problems. Charles

Guy spilled my beer when they jumped on the table and proclaimed in

If you followed the oil trail to the valve cover gasket, then that is what I would put my money on. Also, Charles has some good tips/ideas in his message, too...

NOI

The oil seepage definitely starts at the rocker arm covers. I didn't think gaskets could fail after only three years (about 12k miles for me). But I think the head gasket may also be leaking (120k miles on them). There's a thin heat shield or piece of sheet metal right under the exhaust manifolds that's covered in oil. Do you know if that's mounted above the head gasket or below ? Thanks again.

Anything can fail at anytime. There is no reason to believe that since you changed them 3 years ago, that they're still fine. If the sheet metal is right under the exhaust manifolds and the exhaust manifolds are bolted to the heads, it would lead me to believe that the head gasket is below the sheet metal. As far as I've seen, the head gasket usually leaks coolant before it leaks oil. Again, like the others have said, it's probably your valve cover gaskets. You're making this harder than it actually is. Don't rule out the obvious stuff.

-Bruce

I just had to change the valve cover gaskets on my '84 T/A 305. The old ones were 6 years old with about 25k miles. I would say the valve cover gaskets are your problem.

Chevy 305. You have your answer from others here.

Notorious oil leaker, always was, always will be :(. CHEVROLET stands for Check How Every Valve Rusts or Leaks Every Time.

As others mentioned, easily correctable (for a while) by using good gaskets such as Felpro made ones. Will run you under $15 a set, and maybe another $5 for the Felpro spray tack adhesive.

Always remember that the gasket, not the goo you put there does the sealing.

Charles gave you straight shooting advice on the valve cover straightness. That is critical.

Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 27k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 143k and still going.... '91 S10 Blazer 4.3Z

all chev small blocks are notorious for leaking valve cover gaskets. don't use silicone with the gaskets, it just makes the gasket slippery and they'll slide out of place. I use Permatex High Tack. it's super sticky and doesn't get hard. follow the directions and they won't leak. tighten the bolts firmly with a nut driver, too much torque deforms the cover and splits the gaskets. be sure the covers are straight and not deformed.

You've been given the answer several times. The valve cover gaskets are the most likely place to start so don't hesitate to do it. You can always Gunk the engine clean and then run it while you inspect for leaks but it's most likely from those gaskets. Make sure they are not distorted by the retightening you did. Lay them out on a real flat surface and get them as straight as you can. I like to use Permatex to hold the gasket to the cover as it stays flexible. Use the best Felpro gasket you can find. I like the rubberized ones but that's just my preference. You can also use "spreaders' under each bolt if yours are on the lip of the cover to spread the tension out over a larger area of the gasket.