Newbie Question re: M-25 XPB winterization - is 2 gallons of -100 West Marine antifreeze enough?

[Monheganlover]

Happy T-day! I decided to do save money and winterize my Catalina 310 myself this year. I used to pay the yard to do it. I researched winterization processes pretty thoroughly in advance on this forum and others. I live and keep the boat in the Chesapeake Bay area where our winters are generally pretty mild. It almost never gets much below 20 degrees F and never for very long if it does. I used -50 West Marine antifreeze for the fresh water systems. I ran two gallons of -100 undiluted West Marine antifreeze through the engine's heat exchanger using the Sea-Flush system. My wife confirmed she saw the antifreeze come out the exhaust.

Here is my question. In reading on this board, I have seen some people mention they use 2 gallons of anti-freeze for the M-25 XPB and others say they used more, some up to 5 gallons in a bucket. Do people feel like two gallons is enough or would more be better? I am on the hard now but if I only ran the engine long enough to draw a few more gallons of antifreeze through the engine that shouldn't do any harm. Having said that, no point it doing it if 2 gallons was enough.

Thanks!

 

[dmax]

I have an M25 with a 3" heat exchanger - 2 gallons is plenty. You want to make sure what comes out the exhaust is the same color as the anti-freeze (i.e. not diluted and light pink) - if that's the case, you should be all set. In the future, you can drain the muffler and the heat exchanger (remove the zinc to do this) which will lessen the amount of dilution. I use about 1 1/2 gallons for the engine.

 

[Claude L.-Auger]

Don't rely on just the color of what comes out. As dmax says, it gets diluted and relying on the color for the untrained person becomes a matter of perception. Get a tester (generally less than $10) and take a reading after you're done feeding the antifreeze through the system. If you're happy that it's temperature resistant enough for your area, the job is done. If your not happy, run some more through it and test. I live in an area where it gets to -30 and I don't want to take a chance. An engine and all related parts are much more expensive than antifreeze and a tester ! Yes you can run it on the hard. Just have someone with a bucket collect what comes out of the exhaust. You can then easily test and you can dispose in a safe environmental place. Have a nice winter.

 

[Justin_NSA]

Isn't your heat exchanger a closed loop system? It always has an antifreeze mix like a car. Are you talking about the raw water cooling system that needs to be winterized?

I would invest in a inexpensive refractometer to test your mix freezepoint. Got mine from Amazon

 

[Monheganlover]

My heart exchanger is a closed loop freshwater/antifreeze mix cooled by seawater in the heat exchanger

 

[Peggie Hall HeadMistress]

What did you do to winterize your toilet?

--Peggie

 

[Monheganlover]

What did you do to winterize your toilet?

--Peggie

I just pumped some pink antifreeze through the system

 

[Monheganlover]

I just pumped some pink antifreeze through the system

I forgot to add that, since my toilet is the Raritan Freshwater Flush, all the intake lines were winterized when I did he fresh water system

 

[Peggie Hall HeadMistress]

Oh good...that was all you needed to do to a toilet that uses pressurized fresh water.

Unfortunately too many owners of sea water toilets make the mistake of just pouring antifreeze into the bowl and flushing it, often resulting in a cracked bowl. Doing that only protects the bottom of the pump and the discharge line (and the tank of course). To winterize the entire system, it's necessary to remove the intake line from the thru-hull (close the seacock first!) and stick it into the jug of antifreeze. If you've teed your head intake line into the head sink drain, you can make sure that seacock is closed, pour the antifreeze down the sink while flushing the toilet.
Either way, pump the entire jug through the toilet all the way into the tank. This protects the intake line, entire pump and the channel in the rim of the bowl in addition to toilet discharge line and tank.

Do NOT put antifreeze into any onboard treatment device (LectraSan, ElectroScan or PuraSan)! Follow mfr's instructions for winterizing them. If you don't have those instructions, I can post a link to them.

Happy Thanksgiving all!

--Peggie

 

[CowboyWay]

Oh good...that was all you needed to do to a toilet that uses pressurized fresh water.

Unfortunately too many owners of sea water toilets make the mistake of just pouring antifreeze into the bowl and flushing it, often resulting in a cracked bowl. Doing that only protects the bottom of the pump and the discharge line (and the tank of course). To winterize the entire system, it's necessary to remove the intake line from the thru-hull (close the seacock first!) and stick it into the jug of antifreeze. If you've teed your head intake line into the head sink drain, you can make sure that seacock is closed, pour the antifreeze down the sink while flushing the toilet.
Either way, pump the entire jug through the toilet all the way into the tank. This protects the intake line, entire pump and the channel in the rim of the bowl in addition to toilet discharge line and tank.

Do NOT put antifreeze into any onboard treatment device (LectraSan, ElectroScan or PuraSan)! Follow mfr's instructions for winterizing them. If you don't have those instructions, I can post a link to them.

Happy Thanksgiving all!

--Peggie

this is excellent and thorough advice. Wish it were in the manual for the boat

 

[njlarry]

I always use 4 gal -50 in mine as AF is cheap vs cracked parts. Always drain system first so less dilution. As menntioned a simple refractometer is the best way to check. You can drain a small sample from the heat exchanger zinc or collect sample from exhaust just as you shut down.

 

[Monheganlover]

I always use 4 gal -50 in mine as AF is cheap vs cracked parts. Always drain system first so less dilution. As menntioned a simple refractometer is the best way to check. You can drain a small sample from the heat exchanger zinc or collect sample from exhaust just as you shut down.

Thanks! I see your boat is in Rock Hall, MD. I keep my 310 on the West River on the western shore. But I do plan to sail to Rock Hall next spring. Would love to meet you and buy you a beer then if that is of interest. I believe you can PM me on this forum if interested. Thanks again.

 

[RitSim]

Remvove the heat exchanger zinc to drain the heat exchanger, then reinstall the plug. Open the water muffler drain and then close the valve. Then pump antifreeze thru the system - less dilution.

 

[Maine Sail]

This may help: https://marinehowto.com/engine-winter-freeze-protection/

 

[Monheganlover]

This may help: https://marinehowto.com/engine-winter-freeze-protection/

Thanks! Very helpful as I am going to redo it all tomorrow. I use the SeaFlush setup which makes this all easy. Going to flush with five gallons of fresh water as the Westerbeke manual for my Universal M25XPB recommends, then drain the as much water as possible at the zinc opening and check/replace the zinc, drain and replace the fresh water side antifreeze at the petcock, even though it tested just fine with my cheap Prestone tester vis a vis freeze point, but it is old, and then run 5 gallons of antifreeze back through the raw water circuit. I don't have a refractometer, yet, but since I saw antifreeze out the exhaust when I ran two gallons of pink -50 through an undrained system I am confident I will be good. And I am using -100 antifreeze just to be safe which is what a lot of the yard techs do down here. I think this is all consistent with the advice here. And, yes, much cheaper than either paying someone or replacing a busted heat exchanger.

Btw, just made a donation to the MarineHowTo site. Hope it helps. Great info and greatly appreciated!!!

 

[Monheganlover]

Stupid question for anyone with the Universal M-25 XPB - where is the drain on the engine block for the freshwater coolant? Is there anything other than the petcock on the heat exchanger itself?

 

[Monheganlover]

Oops. I should RFM. Think I found it.

 

[njlarry]

Follow Maine Sail and you wont go wrong. I have learned so much from his how to web site.

 

[Hayden Watson]

You can greatly reduce the quantity of antifreeze needed to get full protection by draining the water out of the heat exchanger and the muffler before you add the antifreeze. After I drain all of the water I can, I start the engine for a few seconds with the thru hull closed and the sea strainer open so that the raw water pump expels the water in the pump and hoses. After all water has drained out, I pump the antifreeze through the system. That way you are not diluting the strength with the water in the system.

 

[Monheganlover]

Good advice. Thanks. I use -100 just to be safe. We have very mild winters here in Ches Bay land so pink is probably ok...but,