View Full Version : Cannot get valve covers to stop leaking!

12-22-10, 06:10 PM
Hey guys,

Haven't been around much due to a busy semester, but winter is here and I am polishing up the '89 Brougham d'Elegance for the new year.

I've been doing a tune-up lately, and I'll work on the plastics (destroyed in Texas heat) in January. But at only 69,000 original miles, she's pretty nice, age still got to the old cork valve cover gaskets.

I replaced them last week. Took her for a spin, then lo and behold.. massive old leak! I screwed them up. The driver side gasket was not even on the mating surface and I was losing massive amounts of oil. And the passenger side gasket disintegrated at one of the bottom bolts.

So I drudgingly began the entire process anew a few nights ago. I bought another set of Felpro cork gaskets and more RTV gasket silicone. I made sure the gasket stayed between the mating surfaces (and that's a pain with all the hoses on a 307 motor). I have a service manual so I've been following it to a tee. Torqued the bolts each to 10 ft-lbs. A couple hours later, I fired her up, and got her good and hot to check for leaks. None that I could see!

I used a mirror tool to check the underside to look for wet spots and there were none. The motor still smoked, but I figured that was from grimes that got there when I screwed up the first time. And most of it burned off. I was good.... for a little while.

I drove up to Dallas last night (250 miles). I get home, there's a puddle forming under the car... crap! I look and sure enough, it's my passenger valve cover AGAIN! It's leaking at the bottom near the firewall (same place as the gasket disintegrated before). And I think the driver side may be leaking there too (sludge appears "wet" directly under the valve cover).

So what am I doing wrong?? I clean both surfaces completely, and this takes hours, especially when you're removing freshly dried Permatex. I torque the screws correctly. And still it leaks. :crybaby: Any tricks about valve cover gaskets I oughtta know about?


P.S. Other parts of the tune-up went real well, and she's performing very well :D

12-22-10, 06:19 PM
is it possible that the valve cover or head surface warped a little causing the gasket to get compromised?

I've never done this myself, but I think my 87 will need new cover gaskets soon...any experts know if it could have warped?

12-22-10, 06:22 PM
Forget the cork gaskets. Get the good ones. Rubber composite with the metal cores. Glue them to the covers with RTV. Let it set overnight. Clean the mounting surface on the head well. Mount them back up, and snug down.

Make sure the covers are straight first, though. Check them on a nice flat counter top or glass surface.

12-22-10, 07:18 PM
When I did mine, I used rubber gaskets and they haven't leaked since.

12-22-10, 08:05 PM
What about using gasket maker? Does that stuff work?

12-22-10, 08:44 PM
Gasket maker is good for machined surfaces. Not for a sheetmetal surface sealing cast iron.

12-22-10, 11:54 PM
Thanks Jay! I'll try those rubber and metal-core gaskets next (hopefully for the last time).

I am worried though, because I had to really yank the covers off after the first time since I used Permatex. They did get slightly bent in a small area, but I used Vice Grips to bend it flat again. It felt flat to the touch (and to the eye). Is there any tolerance for that?

12-23-10, 08:13 AM
Using cork gaskets builds character. See the crap we had to use back in the day? It really makes you appreciate modern technology. A hammer and dolly or hammer and flat piece of steel should get the valve cover flat enough to seal. This would be a great time to invest in some chrome valve covers.

12-27-10, 01:22 AM
When I did mine, I used rubber gaskets and they haven't leaked since.

I use this

on the valve cover side. Also make sure everything is clean.

12-27-10, 04:11 PM
When i did my 65 Cadillac and my 71 Lincoln, i had the same problem, so in the end i used 2 gaskets on each valve cover, and some hermatite blue,
sealed up nice

01-04-11, 02:18 AM
Here's another question. Do I put RTV silicone between the gasket and the head? I know it definitely goes between the cover and the gasket, but I'm not sure about the head surface.

01-04-11, 07:07 PM

01-05-11, 12:29 AM
Thank you. Will report back on the success of the job, but now I have a strange water leak before the car goes anywhere. Oh the endless joys of automotive maintenance! :D