Re: Radiator under constant pressure?
 

If your cooling system is working properly the system will go from positive pressure to negative pressure as the coolant expands and contracts from temperature. Your problem could be as simple as a defective radiator cap or the wrong radiator cap. If you have the factory by pass hose i cannot see how you would get a air lock.

Re: Radiator under constant pressure?
 

Surgery consisted of a tube installed in my stomach to get ready for dialysis. Stomach muscles are still sore so I can't look at car yet. I will check radiator cap pressure and swap out with a lever type. The car is new build and has had pressure since day1. Ruling out the easy stuff first. Cap, electrolysis, hose and over flow tank, vacuum system down, retorque head bolts

Re: Radiator under constant pressure?
 

I had this problem once, mine was a aluminum head on steel block with a single layer head gasket. I chased the problem all season, water was not getting in oil or coming out of exhaust so I just left the pressure lever up on the radiator cap. When the engine was torn down the head had warped some, resurfaced head and used Cometic MLS gasket and never had anymore issues. I do believe the MLS gasket would have fixed it. I dont know if you have aluminum head are not, just passing along what I came across.

Re: Radiator under constant pressure?
 

I don't have aluminum heads, but now that you brought up warpage I did have a hard time finding heads that were not warped so bad and can be used. These head are about..008 warped but the cc's were high enough I was able to cut warpage out and get to correct cc. I had a couple heads that were. 025 warped and could not use. I wonder if these have warped. This will be at bottom of last to check after I finish healing and checking the basics first