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Old 09-25-2019, 04:22 PM
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Orion C&C 33 Orion C&C 33 is offline
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Quote:
Originally Posted by capnward View Post
No need to stress yourself yet about removing the head. Just check the manifold outlet. That is where obstruction usually occurs. There could be junk (impeller pieces? rust?) visible at the outlet as soon as you open it up. You might be able to remove the bigger pieces with needle nose pliers.
This not a pressure test, but an airflow test. Blow through a hose into the manifold inlet with the outlet open, and see if any crud comes out, or if you feel any resistance. If there is little or no airflow when blowing hard through a hose, and you can see no crud at the outlet, run water from a hose into the intake of the manifold, and out of the outlet into a bucket with another hose. Much easier than removing the head. Flushing the manifold is not a winter project, should take a day with the right hose fittings. No need to use acid, just water pressure. Check running temperature after flushing the manifold. If it is still at 160 with no thermostat, look in the heat exchanger.
Besides, if your engine holds at 160F with the thermostat removed, you no longer have an overheating problem. Your thermostat when open at 140F apparently still obstructs the flow enough to increase temperature by 40F, which combined with the other obstruction, makes the engine overheat. Running without a thermostat is common. Without a thermostat it should run lower than 160F, so there is evidence of a blockage, probably at the manifold outlet. My thermostat keeps the temperature at 160. Let us know what you find at the manifold outlet.
Good advice... I'll check the manifold and get back to you over this weekend.
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