Losing Coolant

[JNash]

Good morning all,

Couple weeks ago my wife and I were on our Friday evening sunset cruise to dinner and the Engine temp alarm came on, temp maxed at 205. 22 Axis T23... luckily we were right at their dock. Our neighbors talked me into trying to get it home and it ran fine all the way back after it had cooled down. My mechanic on our lake noticed a slight crack in the coolant reservoir and replaced it. We topped off the coolant and its lost another entire reservoir of coolant in about an hour of testing. He said part of that is probably normal due to it possibly having air in the system. We dont see any leaks from anywhere else. has anyone ran into this and found an odd leak point? Engine oil looks perfect. recently summarized and oil looks brand new.  Our last drive the coolant barely dropped so hopefully thats all it was. I'm nervous to get far from our dock until I'm more sure of it. 

 

[Nick55]

Was the reservoir empty and it was low on coolant?  If so, there should have been an external coolant leak right?  The diagnosis makes sense IF those answers are yes, and there likely was some air in the system if it was just refilled when the repair occurred.  Makes me wonder, does anyone use a vacu-fill tool like what’s used in automotive applications?

 

[ahopkins22LSV]

I had a leak from the cap being installed incorrectly on ours and I didn’t notice it until the temps started fluctuating. I topped off the reservoir probably three separate times before it finally purged the system. Used almost a gallon. I would just keep filling it, I even carried some with me for a while. 

[JNash]

Thanks for the advice everyone!

[dalt1]

The coolant tank has a High and low mark on the side. At a cold engine, should it be between the marks or is that at hot temp?