Universal M18 coolant leak on the hard in winter in SE MI.

[Kopite]

Hi, my engine ran fine all last season, no overheat and zero coolant loss. Now, after most of the winter on the hard, I found about 20cc of green coolant in the bilge. I know this is fresh leakage ( can see it came from under the engine), but cannot see any drips or other evidence of where the leak is. I winterized the motor just as I have the last three years and have had no previous issues.
I’ll be checking hoses/connections first, but was wondering if anyone has any ideas on likely suspects to check ?
My coolant overflow does go to the bilge, so it’s possible that partial freeze (expansion) of the coolant simply pushed a little out, but it has not happened before.
I’d like to get it resolved now vs losing part of next season so any help you can offer would be great !
Thanks,
Andrew

 

[Gunni]

Shrinkage happens! Fittings, hoses, and seals get loose. I see a bit of seepage every winter. Maybe 20 cc. Keep the coolant topped up and track if it concerns you.

 

[Kopite]

Thanks Gunni. Glad to hear I am not the only person to see this happen..

 

[py26129]

Ditto on my Yanmar. I suspect one of the drain cocks on the block. I'm replacing them this spring.

Matt

 

[Capt jgw]

Keep in mind we had one of the coldest two week periods ever here in Michigan. Things that weren't effected the last few years might have been this year. In extreme cold the metal fittings will shrink more than the rubber hoses so leaks could have occurred, they should tighten back up in warmer temps.

 

[Davidasailor26]

Happened to me too over a winter. After no leaks during the season a small amount of coolant appeared under the engine. Checked the hose clamps and a couple were loose.

 

[Kopite]

All, thanks for the replies. It’s great to have a helpful forum like this - otherwise I’d have been tearing things apart at the weekend....

Andrew