• Mobile App For Android Now Online!

    Download it here. The app is searchable in the Google Play Store under Sailboat Owners.

    Sorry iPhone/iPad users, we are still waiting on Apple. :(

    Click the X in the upper right corner to make this go away

How much antifreeze for wintering the engine?

Dec 29, 2017
22
Catalina 310 Aww Shucks Middle River
I have the standard engine on the Cat 310 and was wondering how much antifreeze others use for winterizing? The person that I bought the boat from gave me a rule of thumb guide, “have someone watch the exhaust area, when the pink starts coming out put another half gallon through and you are fine”, which has tended to be between about a gallon to a gallon and a half. Only reason that I ask is that my slip neighbor, who has a Hunter with a 50hp engine, uses over 5 gallons to winterize. I was surprised that he was using 5X the amount even though his engine was only 2x the size. Any thoughts and commentary from the community are greatly appreciated.
 
Apr 8, 2010
1,178
Ericson Yachts Olson 34 Portland OR
I have been "freeze proofing" my three cylinder Universal for 25 years. Many years ago I replaced the standard engine thru hull with a two way valve version that incorporates a standard hose fitting on it. I have a length of tubing clamped to a 'garden hose' fitting that screws into the top of the thru hull fitting.
That tube is inserted into a one gallon bottle of Pink Stuff RV antifreeze. Engine is warmed up, and then while running @ idle the valve is turned from outside water to the inlet port from the bottle of 'pink'.
A short time later I observe some pink color come out the exhaust and stop the engine. This takes about 3/4 of the bottle.
Thus the system is protected from thru hull, strainer, heat exchanger, and water lift muffler... all the way to the transom.

That nifty little engine intake thru hull is then rotated to "off" until spring. It is a Forespar product, and a great design. (IMHO)
 

Attachments

Dec 29, 2017
22
Catalina 310 Aww Shucks Middle River
Thanks for sharing - my ac unit has something similar. Didn’t realize that something like this was available for the engine water line.
 
Sep 25, 2008
5,481
Alden 50 Sarasota, Florida
It’s the size (capacity) of the water lift muffler that can affect how much antifreeze is required, not the engine. size. As we don’t know the size, it’s beat determined by watching the exhaust color.
 
Dec 29, 2017
22
Catalina 310 Aww Shucks Middle River
Thanks Don - So the words of the previous owner “half a gallon more once you see pink” are good.
 
Jul 7, 2004
6,084
Hunter 30T Cheney, KS
Thanks Don - So the words of the previous owner “half a gallon more once you see pink” are good.
I don't see the need to add more antifreeze once you see it coming out. It has obviously circulated thru the whole system already. "Green" in my case.
 
  • Like
Likes: FastOlson

JRT

Feb 14, 2017
1,525
Catalina 310 211 Lake Guntersville, AL
Timely! Alabama is getting cold at night but our lake never really freezes. I was wondering if I need to do anything and the word at my marina is the lake water is still warm so don't worry. I assume that this process would mean I need to remove the hose from the fresh water value and put it inside a pink RV antifreeze and run it till pink comes out?
 

Scott B

Moderator
Sep 20, 2006
2,656
Hunter 33 Georgian Bay, Ontario, Canada
Be carefull with the advice that once you see pink you're good. If you shut down the engine the first sign of pink, you may not have flushed ALL the water out and it may well be diluted and will raise the freeze protection. I've seen winters with sustained temps right around the 40 below. If you're AF is still diluted you are not protected.
 
Mar 30, 2007
62
Catalina 310 Manalapan, NJ
Two gallons gets the job done nicely. For the air conditioner, 3/4 gallon.
 
Jan 22, 2008
7,155
Beneteau 323 Annapolis MD
Be carefull with the advice that once you see pink you're good. If you shut down the engine the first sign of pink, you may not have flushed ALL the water out and it may well be diluted and will raise the freeze protection.
I agree with Scott. I read that info somewhere, that you may not have deleted all the"pockets" of fresh water. Better to use up all the antifreeze. It's cheap insurance. Unless you need the leftover for thelawn mower?
 
Apr 8, 2010
1,178
Ericson Yachts Olson 34 Portland OR
Be careful of analysis paralysis.:)
Once you look over the transom and see some pink liquid coming out, and decide to shut it down you still have to reach down and pull out the stop cable button or push the stop switch. It's not some sort of micro-second digital device decision. Only caveat is to not wait too long to stop it and suck some air from the bottom o the one gallon jug. I have never come close to that; and the left over 'pink' from each time accumulates enough that by the 4th time around I get one antifreeze application out of those left over quarts.
Another note about intermixing the water in your water lift muffler... there is not all that much liquid in there anyway. :)

One time, several years ago, we hauled out for some bottom work in February. It was the start of a 20 Deg (f) one week cold snap. Once blocked up, the yard guys let me start it up with the antifreeze hose in the jug. When some pink burped out into bucket on the ground I shut 'er down. It was out for about two weeks in sub freezing weather. No problem.
(They did have to 'tent' the hull with plastic and put a "salamander" orange heater under the plastic to do some bottom work...)

Here is a link to our system:
 
Last edited:
Aug 2, 2009
414
Catalina 28MKII Muskegon
I like to bear in mind that I'm not replacing the water in the exhaust system with the pink stuff (preferably propylene glycol), I'm diluting the water in the system with the pink stuff. So, when pink first shows up in the exhaust, what is the ratio of water to pink stuff? Fifty-fifty? With my Catalina 28, which has the Universal M-25 XP, I use two full gallons. That's at least an additional full gallon after pink appears at the stern.

I'm fairly generous with the pink when I winterize my plumbing, both on my sailboat and my travel trailer. An extra gallon here and there keeps my mind at ease.
 
Jan 29, 2018
49
Beneteau 411 Irish Ayes II Branford
What does help is to remove the zinc from the heat exchanger to drain the exchanger (then reinstall till you add the new zinc in the spring) and my water muffler also had a drain that I opened and then closed when empty. This empties the bulk of the water prior to flushing pink stuff. Two gallons does the same thing.
 

Scott B

Moderator
Sep 20, 2006
2,656
Hunter 33 Georgian Bay, Ontario, Canada
This is a very good write up by Maine Sail

 
Jan 24, 2010
344
Catalina 30MKII Ocean City, NJ
i used 8 gallons total to winterize the AC, fresh water, septic, and engine this year.. everything was very pink on the discharge.. i found a neat way to winterize the AC system... i bought a hand pump from harbor freight and back fed the antifreeze in from the discharge port on the side of the hull.. i was able to easily see it going in and coming out from the pickup..
 

Maine Sail

Moderator
Feb 6, 1998
11,052
Canadian Sailcraft 36T Casco Bay, ME
There is not a single spring that passes where we don't get called into to repair freeze damage. In most of these cases the vessel was in fact winterized, however it was winterized incorrectly.

The most common reason for freeze damage is when fresh water plumbing lines are "blown out" using compressed air. The number two reason is due to diluted antifreeze.

We've replaced it all, water heaters, heat exchangers, raw water pumps, valves, faucets, shower valves, fresh water pumps, air conditioner pumps, freeze plugs on RWC engines etc. etc. In every case related to an engine, it has been due to diluted antifreeze.

I would urge anyone in a cold climate, a climate that can see temps below 0F for a day or more, to use a sight refractometer to compare virgin bottle AF with what comes out the exhaust or, even easier, suck in at least 2 gallons more, beyond when you "see pink". For really cold climates a -100 PG or a 50/50 mix of EG will be better than -50F PG.

https://marinehowto.com/engine-winter-freeze-protection/

On the other hand keep doing it as is, it helps keep us in business... (wink)
 
Jun 14, 2010
1,051
Quorning Dragonfly 1200 home
If you're AF is still diluted you are not protected.
Also, the ONLY time to use pink (-50) for an engine is when you're first starting out and want to displace the residual water. I start with purple (-60) and finish with 2 gallons of green (-100). It's a minor expense compared with a possible engine damage repair due to freezing.
One more thing is to leave all valves open (in case any residual water is trapped a closed valve can crack).
 
Dec 16, 2011
170
Catalina 310 Atlantic Highlands
Also, the ONLY time to use pink (-50) for an engine is when you're first starting out and want to displace the residual water. I start with purple (-60) and finish with 2 gallons of green (-100). It's a minor expense compared with a possible engine damage repair due to freezing.
One more thing is to leave all valves open (in case any residual water is trapped a closed valve can crack).
I think some people (like me) are slightly confused by your and @Justin_NSA comments about "green". I've seen purple (non-toxic) and pink (non-toxic) but I thought the color green was reserved for toxic antifreeze. Is there a green non-toxic antifreeze? I assume you're not running toxic green antifreeze through the raw water portion of the engine and out the exhaust onto the ground in your marina.
 
Jun 14, 2010
1,051
Quorning Dragonfly 1200 home
I think some people (like me) are slightly confused by your and @Justin_NSA comments about "green". I've seen purple (non-toxic) and pink (non-toxic) but I thought the color green was reserved for toxic antifreeze. Is there a green non-toxic antifreeze? I assume you're not running toxic green antifreeze through the raw water portion of the engine and out the exhaust onto the ground in your marina.
Good question I should have been clear: The WM brand of non-toxic -100 antifreeze is green, and their -60 is purple, and -50 is pink. These are generally what I use.
Side note: The "toxic" green ethylene glycol commonly used as closed-system recirculated engine coolant degrades quickly in the environment. Propylene glycol is generally recognized as safe for mammals. Ethylene glycol is more toxic but also degrades quickly in the environment.https://www.des.nh.gov/organization/commissioner/pip/factsheets/ard/documents/ard-ehp-12.pdf
 
Last edited: