Overheating Issues, Perplexed

[Michael C Henry]

The deal with the head gaskets is there is a tear drop coolant passage hole at one end of each head gasket and the outline around the blocked passage at the other end of the head gasket. The heads are interchangeable and have the matching tear drop passages at both ends. The gaskets block coolant flow at front of engine. Coolant is supposed to be forced into the front of the block on both sides. The major Coolant flow is supposed to flow to the rear in the block then rise into the heads throughthe open coolant passage in the head gaskets and come forward in the heads. The coolant is then goes to the thermostat in the intake manifold. The small tubes and short connecting hose to the back of the coolant pump and intake manifold is the only circulation of coolant untill the thermostat opens. I perfer a Chrysler thermostat. It fits the T-stat pocket in the housing and has a larger valve area than a OEM Ford T-stat. I use a good grade of thermostat at 180° with a small hole that I locate at the top. I have had problem with that Dexcool coolant ,it clotted and blocked a new radiator in a Toyota Land Cruiser radiator. Radiator shop rodded it out to fix the problem.
If fluid level climbs when engine revs . more than likely it isn't flowing through the radiator. Remember coolant is supposed to fall through the radiator.
There are so many points you need to be sure of . A presure tester would be a great help when checking things out. With the system caped at the usual surge tank,, you can watch the pressure gauge in the tester . Start the engine and watch the presure gauge. If it climbs too fast ( faster than normal heat expansion) that would indicate a cylinder( combustion ) pressure leak into the coolant passages. Another check is to remove the cap on the surge tank and make sure the fluid level is high enough to watch for bubbles rising throuh the fluid . With the engine stoped the fluid should be still. Once the engine is started and running, if bubbles strat rising up through the coolant fluid. the bubbles would be combustion gasses escaping into the coolant (not supposed to happen). Cylinder pressure leak could be a bad head gasket seal, or a crack in the cylinder wall, or a crack in the cylinder head, there are many more variations of this possible. I presonally like the idea that the Dexcool has plugged your radiator and not enough fluid can move through it. Thats a remove radiator - Take the radiator to shop have them test and repair it.