Thread sealant on header bolts?

[David King]

The passenger side valve cover should have two holes in it. The one nearest the firewall is for the crankcase breather tube going into the the air filter housing, the other toward the front of the truck is a larger hole that allows oil to be poured into the engine. The driver side valve cover has one hole for the PCV valve. I recognized this descrepancy in the LMC catalogue and informed LMC and they said they would confer with the "experts" and correct the issue regarding '85 C-10's chrome valve covers.

 

[Truck82]

On cheap chromes I've never had luck unless I take the right angle die grinder th the sealing surface on the valve cover to rough it up good,then I glue my valve cover gasket to the valve cover it's self with 3m super weather strip adhesive and use grease on the other side of the gasket where it meets the head. Those valve covers should have spreaders on the retainer bolts,do you have them? You are missing 1 hole on the valve covers so how do you have them installed. Hole on PS side valve cover should go to pcv breather,hole in other valve cover should go to pcv valve. If you plugged either of those holes,you are going to have leaks,if that breather is plugged you are going to have leaks. If you plugged them both you are going to have big leaks. You will have to fill through the vent or the pcv hole. Unless you have an early manifold on your truck.

I’ve got the little spreaders under the bolts. I have a PVC valve in the driver side and a breather cap in the other. I don’t know how well the pictures are but you should be able to see the oil soaked on the back of the exhaust manifold and that far back bolt.

 

[Truck82]

The passenger side valve cover should have two holes in it. The one nearest the firewall is for the crankcase breather tube going into the the air filter housing, the other toward the front of the truck is a larger hole that allows oil to be poured into the engine. The driver side valve cover has one hole for the PCV valve. I recognized this descrepancy in the LMC catalogue and informed LMC and they said they would confer with the "experts" and correct the issue regarding '85 C-10's chrome valve covers.

I have an open air cleaner. Does that still affect the crankcase breather tube?
Check out my pictures in my last post

 

[Turbo4whl]

@Truck82 Assuming the bolt is the source of the leak, then the head probably has a flaw in the casting or a crack. When you remove that bolt, are the threads oily?

To seal the leak install the bolt with Permatex. Use either number 2 or 3. Silicone will not last. Number 3 Permatex also know as aviation Permatex is probably easiest to apply as it has a brush in the lid of the container. No. 3 is also my go to for sealing leaking valve cover gaskets. Coat both sides of the gasket.

 

[Ricko1966]

Wipe the area between the breather and the oil spot with a rag. I'll bet oil is venting from the breather and running down.