Hello Ed, by opening all drain plugs do you mean remove all freeze plugs and clean the block? By bubble test I mean remove all spark plugs except for the cylinder you want to check, crank the engine and see if any bubbles form on the cylinder that has compression... Do the remaining 5 the same way.
The last thing I did was to remove the thermostat and not over fill the radiator... I was overfilling the radiator before. Same problem. I even tried to run the engine at a higher rpm to maybe clear it out but nope, same issue... I must have a blockage somewhere!
