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Where does the Anti-freeze go?

Oct 1, 2007
1,353
Hunter 44DS Pt. Judith
Hi all:
Every spring after I commission my Yanmar 4JH4E I notice the antifreeze level in the surge tank is down about half way between max and min. I always run it right at the top of max and I know it was there in the Fall. Does anyone have an idea on where the stuff goes?
Thanks
Rick
 
Jan 24, 2011
49
Hunter 30-2 Lake Champlain
My waterheater's in/outlet tubes leaked over the winter.. draining almost all the coolant. Apparently it is not too uncommon for things to get cold and hoses to leak. There was a bunch of green coolant in the bilge, so it was not difficult to track down.
 
Sep 15, 2009
6,241
S2 9.2a Fairhope Al
Hi all:
Every spring after I commission my Yanmar 4JH4E I notice the antifreeze level in the surge tank is down about half way between max and min. I always run it right at the top of max and I know it was there in the Fall. Does anyone have an idea on where the stuff goes?
Thanks
Rick
Rick when it got cold this winter your antifreeze shrunk when it warms back up it will be ok :D

seriously though it may be that while sitting at rest any and all air in the system burped out if you don't have any leaks and also the level could have change some due to the attitude of level that you stored the boat on the hard and also barometric pressure may come in to play as well here now maybe what i have just stated will excite some controversy on this subject :)
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
if you dont have a surge tank, it will be about 1-2" low in the header.. this is normal.

if you do have a surge tank, then even though the water pushed out will collect there and then be sucked back in when the engine cools, there can be some slight loss due to evaporation of the hot water while its in the surge tank, and depending on how much you use your engine and the size of the vent hole in the cap, this could amount to a cup or so....

as long as there is a little bit of water in the surge tank when the engine is cold, it will perform as it was designed to... the marks are only a general reference and not as critical as the marks on the oil dipstick.

and the antifreeze itself does not evaporate, but the water can evaporate out of it... add a cup of water to it, OR... let it go another season as it is and see if its down to the low mark next year when you check it. and then get back to us:D
 
Jun 5, 2004
482
Hunter 44 Mystic, Ct
Where Does the Anti Freeze Go

I have the same engine and same problem, however I noticed that sometime during the winter, I get a puddle of anti freeze under the front end of the engine. What I believe is happening is that the seal of the coolant pump shrinks due to the very low temperatures which results in coolant leakage. Maybe about a pint which is the equivelent with what might be in the expansion tank.

I clean up the puddle put some more ant freeze in the expansion tank and Im good to go for the season. Have never had coolant loss or overheating issue during the season. (Knock on wood)
 
Oct 1, 2007
1,353
Hunter 44DS Pt. Judith
I have the same engine and same problem, however I noticed that sometime during the winter, I get a puddle of anti freeze under the front end of the engine. What I believe is happening is that the seal of the coolant pump shrinks due to the very low temperatures which results in coolant leakage. Maybe about a pint which is the equivelent with what might be in the expansion tank.

I clean up the puddle put some more ant freeze in the expansion tank and Im good to go for the season. Have never had coolant loss or overheating issue during the season. (Knock on wood)
Yuk. This is funny. I also get a dribble of a-freeze right under the fan belt cover each spring. Then I spend all summer worrying about it but once I get the a freeze level in the surge tank stabilized, it stays rock steady all summer. Weird!
 
Oct 28, 2008
24
Catalina 320 Lake Texoma
Rick, if it does it every year, consider it reliable. Put some more in it and enjoy the season. That's why you check and consider it an opportunity to be right every once in a while.
 
Oct 1, 2007
1,353
Hunter 44DS Pt. Judith
Rick, if it does it every year, consider it reliable. Put some more in it and enjoy the season. That's why you check and consider it an opportunity to be right every once in a while.
Well said.
Thanks
 
Feb 10, 2004
2,976
Hunter 40.5 East Greenwich, RI
I have the same engine and same problem, however I noticed that sometime during the winter, I get a puddle of anti freeze under the front end of the engine. What I believe is happening is that the seal of the coolant pump shrinks due to the very low temperatures which results in coolant leakage. Maybe about a pint which is the equivelent with what might be in the expansion tank.

I clean up the puddle put some more ant freeze in the expansion tank and Im good to go for the season. Have never had coolant loss or overheating issue during the season. (Knock on wood)
I have the same issue with my Volvo MD22L-B. I have replaced hoses, tightened clamps, and I still find wet spots on hoses. I cannot find the leak, but it drained my expansion tank every winter until I drained the expansion tank myself before the winter storage. I have no clue why this happens. I don't lose any significant amount of antifreeze during the season.
 
Jan 22, 2008
7,074
Beneteau 323 Annapolis MD
I had the same problem for a couple years. FINALLY found the hose from the expansion tank to the connection right under the HC cap was loose. The very little space apparently had not allowed the hose clamp to rotate and tighten.