Coolant problem

Just starting getting the boat ready for the season. Winterized everything in the fall so figured everything would be fine for the summer. Crawling around the engine room I decided to check all the fluid levels, oil, trans, coolant. Everything was fine except the coolant. Some how I lost 3 quarts of coolant. Now I'm not sure if I topped it off in the fall or not but am worried. The boat goes back in the water next week so I'm a little uneasy about starting her up. If I did top her off last fall where did it go. No signs in the oil. No leaks under the engine. ???

I would lightly bump the starter or turn the crank with a wrench to make sure it is not in the cylinders.
Also water in the cylinders, most would drain into the oil pan over months, and the oil level would show high.

Sometimes the impeller pumps leak very slowly the coolant, and maybe it also evaporated.

If you can not see obvious leaks, you can rent the radiator pressure tester from AZ. Pump it up and see if it holds pressure. You have a closed cooling system, then this is just like your car.

Unless you are certain that you replaced at least what you drained last season &
If no obvious residue of antifreeze evident in bilge, I would consider that you failed to fill it completely due to air locks at time of winterizing. I would make sure to "burp" or compress the elbows to be sure no trapped air this time and if this final fill level remains unchanged at launch I would bet it is good to go.

sdowney717 said:

I would lightly bump the starter or turn the crank with a wrench to make sure it is not in the cylinders.

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This would be wise! I had this happen on a 3208 Cat. One bump of the starter made two bent rods and over $20,000 in damage. Turned out the engine had a bad head gasket that leaked. Never showed in the oil or in sampling.

this tool are your solution

Hugues

Engine Coolant Cooling System Pressure Testing Tester Radiator Cap Tool Kit Set | eBay

use a engine coolant pressure tester tool look online you will find for less that $80 that very nice tool

Hugues

If your heat exchanger has a slow leak, it could end up in you muffler (if you don't have an exhaust riser) Might be worth a quick check.

UNless you KNOW where the coolant went then you have had GOOD advice to manually crank the engine over. DO NOT USE THE STARTER or as said you could turn a problem into an expensive disaster.

There is a good chance from your description that you did not fully fill the engine last fall. Often engines must be run with the exchanger cap OFF to purge the bulk of the air from them. After that a decent run with the cap on should take care of any remaining air. Unless that was done the coolant may have slowly purged the air as the coolant dribbled into those areas. Some engines have air purge hoses leading back to the thermostat housing or the heat exchanger to bleed air pockets positively. Some engine do not so you must work at it.

But be sure for the 10-15 minutes it will take to hand crank.

Do not fool around, hand crank that engine over.

At Autozone, you can get that pressure tester tool for free. Basically you buy it, then return it, this is SOP for their tool rental program, so no need to buy it. It is a very nice tool, I have used it myself. these hand pressure testers work well, less air in there also means less hand pumping to build pressure. A tight system, will mean the pressures hold the gauge level. Changing air temp will have an effect on the gauge reading from say between nighttime and daytime, if you left it hot, and came back cold the gauge reading would drop some..

Yes, safest to turn by hand the engine. Still hard to imaging over months of time water would not drain out into pan and show up as a higher level of oil than should be there, 3 qts is a lot to not show up on a dipstick.

sdowney717 said:

At Autozone, you can get that pressure tester tool for free. Basically you buy it, then return it, this is SOP for their tool rental program, so no need to buy it. It is a very nice tool, I have used it myself. these hand pressure testers work well, less air in there also means less hand pumping to build pressure. A tight system, will mean the pressures hold the gauge level. Changing air temp will have an effect on the gauge reading from say between nighttime and daytime, if you left it hot, and came back cold the gauge reading would drop some..

Yes, safest to turn by hand the engine. Still hard to imaging over months of time water would not drain out into pan and show up as a higher level of oil than should be there, 3 qts is a lot to not show up on a dipstick.

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