Frequently Asked Questions: Cooling System

Parts and Services for the Universal Atomic 4 Engine
Parts: Phone: 717.625.3891 | 410.810.8921 | 717.625.1587 (fax)
Technical Service: Phone: 410.810.8920 | 410.810.8922 (fax)

FAQ: Cooling System

1. I am getting ready to acid flush my engine and was wondering about the themostat. Do I remove the thermostat before the flush, or can I flush the engine with the themostat in if I warm up the engine first? Will the acid do any damage to the thermostat? Any precautions I should take, aside from the normal acid spill warnings?

2. We have a 1972 Columbia 30 with a RWC A4 that was rebuilt in 1997 and is now overheating when at cruising speed (1700). I recently did an acid flush (as per your manual), but the engine still overheats, though not as much as prior to the flush. During the flush, it took about 5 minutes to empty the acid bucket which would indicate blockages in the cooling passages (impeller and thermostat are fine). How do I go about manually cleaning the passages that I can access without removing and stripping the engine down to have everything chemically cleaned out?

3. When is the thermostat housing spacer (OVWJ_13_241) used? I haven't run into one on any engine I've worked on. And do I need one with the bronze casting and current 180 deg stat.

4. Knowing that your freshwater cooling system requires at least two inches of space in front of the flywheel cover to accommodate the belt drive for the sea water pump, how much space does the system require above the engine?

5. One of my freeze-out plugs has developed a slight leak. What options do I have in terms of repair?

6. I got caught off guard when the first snow storm hit our area the other day. My boat was taken out of the water earlier in the week, but I was not able to put antifreeze in the engine before the storm hit. How much damage do you think I have done? It got to the low 20's overnight two times.

7. How important is the internal fitting on the block side plate, the one directing coolant flow to the rear of the block?

8. My engine was running fine then started overheating. There is white billowing smoke or vapor coming from the exhaust. The engine seems to run smoothly but the smoke (vapor) worries me as well as the overheating. The raw water strainer is clean. Could it be the thermostat, and how can I check it?

9. I am getting steam out of the exhaust when running, but the temp guage says 140 to 150 degrees. I did a compression check and the results were 120 psi on two, three, and four, and 90 on number one. I am thinking of a crack in the head or something with the head gaskets. Any ideas.?

10. What type of grease to use in grease cup for water pump?

11. The engine temp goes way up and then falls back down over and over. I have replaced the thermostat three different times, and it still does the same thing. It seems to be the worst when I am motor sailing so the load is the least.

12. Zincs

13. What would cause my engine to run at temperatures below the rating of the thermostat?

14. Why does my engine run at 160 to 170 degrees (with a 140 degree thermostat), even after insuring that my cooling system is well maintained?

15. What would cause the temperature to go above 180 degrees in my late model engine?

16. Bypass restriction in a late model cooling system

17. Operating without a thermostat

18. Operating temperature

19. Re-plumbing raw water cooled engines for better hot water heater performance

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: 1. I am getting ready to acid flush my engine and was wondering about the themostat. Do I remove the thermostat before the flush, or can I flush the engine with the themostat in if I warm up the engine first? Will the acid do any damage to the thermostat? Any precautions I should take, aside from the normal acid spill warnings?; 2. We have a 1972 Columbia 30 with a RWC A4 that was rebuilt in 1997 and is now overheating when at cruising speed (1700). I recently did an acid flush (as per your manual), but the engine still overheats, though not as much as prior to the flush. During the flush, it took about 5 minutes to empty the acid bucket which would indicate blockages in the cooling passages (impeller and thermostat are fine). How do I go about manually cleaning the passages that I can access without removing and stripping the engine down to have everything chemically cleaned out?; 3. When is the thermostat housing spacer (OVWJ_13_241) used? I haven't run into one on any engine I've worked on. And do I need one with the bronze casting and current 180 deg stat.; 4. Knowing that your freshwater cooling system requires at least two inches of space in front of the flywheel cover to accommodate the belt drive for the sea water pump, how much space does the system require above the engine?; 5. One of my freeze-out plugs has developed a slight leak. What options do I have in terms of repair?; 6. I got caught off guard when the first snow storm hit our area the other day. My boat was taken out of the water earlier in the week, but I was not able to put antifreeze in the engine before the storm hit. How much damage do you think I have done? It got to the low 20's overnight two times.; 7. How important is the internal fitting on the block side plate, the one directing coolant flow to the rear of the block?; 8. My engine was running fine then started overheating. There is white billowing smoke or vapor coming from the exhaust. The engine seems to run smoothly but the smoke (vapor) worries me as well as the overheating. The raw water strainer is clean. Could it be the thermostat, and how can I check it?; 9. I am getting steam out of the exhaust when running, but the temp guage says 140 to 150 degrees. I did a compression check and the results were 120 psi on two, three, and four, and 90 on number one. I am thinking of a crack in the head or something with the head gaskets. Any ideas.?; 10. What type of grease to use in grease cup for water pump?; 11. The engine temp goes way up and then falls back down over and over. I have replaced the thermostat three different times, and it still does the same thing. It seems to be the worst when I am motor sailing so the load is the least.; 12. Zincs; 13. What would cause my engine to run at temperatures below the rating of the thermostat?; 14. Why does my engine run at 160 to 170 degrees (with a 140 degree thermostat), even after insuring that my cooling system is well maintained?; 15. What would cause the temperature to go above 180 degrees in my late model engine?; 16. Bypass restriction in a late model cooling system; 17. Operating without a thermostat; 18. Operating temperature; 19. Re-plumbing raw water cooled engines for better hot water heater performance

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