Eliminating Overheating due to white algae buildup.
Recently, I had a problem with my home air conditioning. The condensate line got clogged, started to back up, and was leaking in the garage.
The service company told me that the condensate line can get clogged from algae growth and has to be vacuumed out if the algae builds up. The algae has a white slimy appearance. When I talked with the AC tech about preventing the algae build up, he suggested pouring a half cup of vinegar a couple times a month into the line where it starts at the air handler.
There are several photos at the beginning of this thread in post [HASH=108]#1,[/HASH] they show a substance on the gaskets and the oil cooler cover. It does not appear to be sand, salt, or sediment. It is soft and white or clear like silicone. What happens with my AC condensate line leads me to believe that the same thing is happening when the engine is cold. After the engine stops running, the warm wet environment of an open loop cooling system provides the perfect environment for internal algae build up. Even if the cooling system drains down, there is still an abundance of moisture left inside the cooling water passages. Here is a photo of the portside oil cooler cover. Conditions: The boat sits covered along side my house; The engine bay is always dry; May 1, 2020 was the last time it was on the water; The oil cover was clean when I launched the boat to test run it after fixing a milky-oil problem; After that, the engines were run on the hose for 5-10 minutes apiece semimonthly during the lay up. This is what the oil cooler cover looks like now after running for 10 minutes on a salt removal solution.
View attachment 136392
I do not know what happens to the algae after it dries out, but I think it turns brown and scales, leading to constrictions in the water jackets. I have observed algae in a soft form throughout the oil cooler, exhaust cooling ports, both sides of the head gasket, and thermostat. It does not appear to present in the cylinder water jackets in the soft form. Along with sand, salt, and sediment, algae build up can contribute to engine overheating.
Now I am pursuing ways to prevent or eliminate internal algae build up. I am sure that flushing with dish soap, vinegar, and various products are beneficial. Recently, the portside thermostat plugged twice, when I began running the engine on the hose. The first time, I stopped the engine, removed the thermostat, and cleared the plug. The second time, while it was running. I used an air bulb to backflush the thermostat through the water pilot opening. That worked. I think compressed air could do the same. I have removed the intake screen, plugged the cooling water supply hole in the impeller housing, and filled the cooling system with white vinegar through the flush port. A week from now, I will drain the cooling system at the impeller housing, flush the engines with dish soap, and remove the oil cooler cover to see if any of the buildup pictured above gets removed.
Looking for ideas and suggestions.