Coolant choice for the Universal m-25

[Brian]

Having just changed the coolant to a long life type to cut down on the dreaded change over air locks, I am having second thoughts on the compatability of long life coolant wiht the engine. I flushed the old out pretty well, but I am more interested in the collants effects on teh engien components and gaskets.Is there anyone who has good information on this compatability?

 

[John]

Coolant

I have had it in my M25 for the start of a fourth season with no apparent negative affects. I had to do the exhaust elbow over the winter so some of the antifreeze drained out. I added the same long term (orange) type of antifreeze and am now working on removal of air in the system.

 

[Alchemist]

Use 50% Automobile Antifreeze

The standard automotive antifreeze (50% water, 50% ethylene glycol with some greenish-yellow florescent dye and anti-corrosion additives) works BEST. You may not discharge this to the environment (you can, but doing so is against the law, and it's very toxic), so the ethylene glycol has some negatives. The red -50 degree water system antifreeze works (sort-of) in your engine, but is not nearly as good at heat exchange is the ethylene glycol mixture. In addition, if you are just a little off in mixing this stuff, the freezing point goes way up (I don't recommend propylene glycol as an engine entifreeze).When I had some engine work done on my C-30T with a Universal M-25XP by Torresen Marine, they re-filled the heat exchanger with the automotive antifreeze, so it seems that the experts in this part of the world agree with me.SteveHolland MI

 

[Brian]

M25 Coolant

Thanks for the reply. I apologize for my atrocious spelling, I was in a hurry on a strange computer sitting sidesaddle. I'll leave the long life stuff in there unless I hear differently. The Prestone 5/150 does say "compatible with all engines" on the container. It's the Dexcool that has all the warnings on it.