Personally, I wouldn't put any kind of "miracle, gooey, sealing magic solution" in the cooling system. It may have been alright on cars back in the 50's but I've personally seen it cause more problems than it temporarily fixed. Then when you go back in to repair it correctly, it's a nightmare to get the "magic solution" removed to prevent further problems.

From what I've seen in the FSM, a magic solution will cause problems with the thermostat venting and probably reek hovoc on the monovalve, at least. There is a lot of information here on this forum to help you through doing it correctly, once.

I'm not sure, but the thermostat venting may be causing the bubbling. Also, a head gasket problem usually results in a loss of coolant. Are you seeing coolant levels drop?

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Sam

84 300SD 350K+ miles ( Blue Belle )