Coolant bottle empty

[krisnowicki]

I have a FWC merc that I just finished putting. The coolant bottle only has an outlet on the top, is this just an overflow bottle??

When we come in it is full after a weekend on the water but the next week it will be empty when I pull the boat out?? There is no coolant in the bilge or anything... What would cause this?

 

[krisnowicki]

Re: Coolant bottle empty

temp never gets above 170 even under load.

 

[stonyloam]

Re: Coolant bottle empty

Same as your car. When the antifreeze is heated it expands and the excess flows into the bottle (full when hot). As the antifreeze cools it decreases in volume which creates a vacuum and draws the af from the bottle back into the engine (empty when cold). Sounds like it is working just fine. There should be a tube from the top of the bottle to the bottom to suck the af back into the engine.

 

[stonyloam]

Re: Coolant bottle empty

Don't know what your system is, but there is usually some antifreeze in the bottle when cold. Are there some marks on the side? Like hot level, cold level, or full and add. one other thing, if there is some air in the system (likely since it is new) the air will be forced out before the antifreeze, and will be replaced by antifreeze as it cools, so don't be surprised if the level in the bottle drops the first few times out. Just add AF to the "cold line" after it cools, it should stabilize as the air is purged.