I have two Waterloo style engines, a Gault and a Majestic. They both make the water in the water hopper bubble when on compression. I have put a new head gasket on the Gault and it still leaks when it is running, but I have not done anything to the Majestic. Neither of them have any cracks in the heads that I can see. The old head gasket on the Gault showed a bad spot that was causing the leak. Now I can not get the new gasket to seal completely. How can I get the head gasket to seal or is there a proper procedure for this?