Volvo Penta 5.0 GL valve cover leak

[Augoose]

All,
I've recently installed two new heads on my 5.0GL following an overheat. I'm getting a persistent valve cover leak on the starboard side rear edge of the valve cover. Using new Fel-Pro rubber gaskets torqued per service manual. Leaked with old valve cover and I just replaced my OEM cover with a new one, still leaks.
I've read that you "shouldn't" need to use gasket sealer or RTV but I'm at a loss here. Can someone recommend a product and/or technique to help me out? Permatex gasket sealant? RTV? Torquing the four bolts center then out or outer first then center? At this point I'm ready to mix an entire tube of JB Weld, spread it around and let her have it.......

 

[ESGWheel]

Others with more experience may better solutions but here is my suggestion:
Remove the leaking valve cover and pull out the gasket. Clean it all up. Place the cover on a known flat surface (a thick piece of glass will work, or if you have one of those glass top stoves, that should work too). And then using a feeler gage check to see if the cover itself is flat. I do not know what the spec is but start with a 0.003” feeler and see if it fits under the cover. Ideally it should not anywhere around its perimeter.

Given the gasket fits up inside the U channel of the cover, its also possible to have some sort of deformation causing the gasket to not be ‘flat’. So put in a clean new gasket and redo the flatness check.

Assuming all is good, then place it on the engine and bolt it down, do the same check with a feeler gauge to see if the two surfaces are properly mating.

If all is good, gasket sealer

 

[Jeff J]

Was there a gasket material change? On some applications I have worked, a paper or fiber gasket was replaced with a thicker silicone gasket. The silicone gaskets leak like a sieve because they distort and squeeze out of position when torqued to the book specifications. The proper torque for the silicone gaskets is considerably less than what the book says.

 

[Scott Danforth]

Your valve cover is most likely bent. Generally the center bolt valve covers do not leak

 

[kd4pbs]

FelPro's blue silicone gaskets work well. FelPro's older black rubber gaskets used to be the first thing that went in the trash when they came in the master rebuild kits. If the valve cover is truly OEM, it will have a lip on the inside and on the outside. I have seen valve covers that claim to be OEM that did not have the lip on the inside.

 

[Augoose]

Thanks all. The valve cover is as I said new but I'll check it for flatness and the internal lip. Interesting that I'm having trouble not only with my OEM cover but this brand new cover as well, and only on this side of the engine. The gasket I was using was Fel-Pro's blue silicone. Possibly the service manual torque specs are too much. These are exactly kind of suggestions I was looking for. I picked up Fel-Pro's thicker cork gasket today which has a metal core so I plan to try that along with a bit of gasket sealer in the corners.

 

[Scott Danforth]

You really can't over torque the center bolts. The bolts will break above 20 ft-lb

 

[Jeff J]

In the valve cover gasket example I posted, the screw torque is 65 lbs/in by the book. The aftermarket silicone gaskets get 20-25 lbs/in. There should be something written somewhere if torque required is different.

 

[Scott Danforth]

The small screws would never make it past 20 ft lb

 

[Augoose]

Thanks all. I ended up installing Fel-pro's performance cork gaskets, part # 1648. They were a few mm's thicker and being rigid, stayed in the valve cover channel far better than the blue silicone ones. Seems another example of you get what you pay for as they were 3x as expensive. Cleaned all surfaces dry and torqued per VP SM to 106 in/lbs and that solved the oil weeping. Thanks all for the assistance.