Yanmar 3jh3e Winterize

Sep 11, 2019
165
Hunter 386 Lake St. Clair
Hey Guys,
My local guy charges $150 to winterize our engine. We did it last year, as it was our first and had enough things on the plate. Looking at doing it ourselves. We're not pulling out until late October in Michigan. I don't know if I'll have access to fresh water. I'm having a brain fart here. Can I just run 5 gallons of antifreeze through the engine, or does the engine need to be warmed up first? If it's the latter, I might be stuck.

Thanks,
 
May 17, 2004
5,028
Beneteau Oceanis 37 Havre de Grace
You can just run antifreeze through and it will be winterized.

Having said that just before winter is a good time to do an oil change, to get any combustion byproducts out of the oil before it sits all winter. To do that you would need to warm the engine. I usually warm it up, do the oil change, then run the antifreeze through to circulate the fresh oil.
 

RoyS

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Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
Suggest you run engine while still in the water. When the oil is warm pump it out. Replace the oil filter. Add fresh oil. Just before pulling the boat out put the engine raw water intake line into a bucket with a gallon of nontoxic antifreeze. Run engine until antifreeze is all pumped through. Should take only seconds. Shut down engine and do not run again until next season. There are other things that the engine needs as well but that is probably what you got for $150.
 
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Likes: sail sfbay
Sep 11, 2019
165
Hunter 386 Lake St. Clair
Nah, I checked last year....all they did was winterize the engine. A little pricey. I changed the oil this week and antifreeze in the system. I also cleaned all the strainers. I did the fuel filters a couple weeks ago, so I'm pretty much ready. Still want to go out a couple more times.
 
May 17, 2004
5,028
Beneteau Oceanis 37 Havre de Grace
Sounds like you’re pretty well on your way. A 5 gallon bucket and some antifreeze should have you all set.
 
Jan 7, 2011
4,726
Oday 322 East Chicago, IN
I change my engine oil before haulout (usually mthe morning I haul out)…run engine to motor to the fuel dock, pump out holding tank, back to slip and change the oil. Also usually water tank while still on shore power, and if I have time, isolate and drain water heater.

then once on the hard, get the pink stuff out to winterize the potable water system, toilet, and run a few gallons through the engine. oh yeah, I usually splash a little in the bilge in case I get water in int there…don’t want it to freeze and damage the bilge.

Disconnect batteries, put winter cover on, kiss the old girl goodnight for winter and head home…

OK, my wife will correct me and say I go see the old girl every few weeks, check the cover, check the batteries, etc…

Greg
 
Last edited:
Sep 11, 2019
165
Hunter 386 Lake St. Clair
Hey Greg.. I do the same. What can I say, I enjoy fixing her up! I'll put her to bed, only to be back a couple weeks later as well.
 
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Dec 14, 2003
1,393
Hunter 34 Lake of Two Mountains, QC, Can
All good advice here and since you mention changing the antifreeze it means you only need to winterize the heat exchanger. Therefore a 5 gallon bucket of antifreeze ought to do it. You can wait until you're out of the water so long as you have someone with an empty bucket to collect the water/antifreeze out of the exhaust and dispose of it safely and responsibly. One word of warning: the heat exchanger and exhaust system is full of water so when you first see antifreeze coming out of the exhaust pipe doesn't mean that what's left in the system is freeze proven. I am in Canada and we do get several days below 20 and even 30 F below zero !!! So I run antifreeze through the system until what comes out checks at -35 F. That keeps it safe. Good luck.
 

RitSim

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Jan 29, 2018
406
Beneteau 411 Branford
On my previous C30, I drained the water muffler (had a petcock on the muffler base) and drained the heat exchanger by removing the zinc to check it. My theory was that with less water in the system to dilute, thre was less to dilute the antifreeze
 
Sep 11, 2019
165
Hunter 386 Lake St. Clair
Thanks. Reading my Yanmar manual, our engine has 2 seawater drain cocks. Once we get on the hard, I'll drain those first before I flush the antifreeze through the system. Good idea!
 

RoyS

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Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
Reading my Yanmar manual, our engine has 2 seawater drain cocks. Once we get on the hard, I'll drain those first before I flush the antifreeze through the system. Good idea!
If you have a heat exchanger your engine should have antifreeze in it already. The flushing business is for the raw water pump, heat exchanger, exhaust plumbing, and muffler.
 

RoyS

.
Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
You may already know this; when you drain your engine block and exhaust manifold you must open a bleeder vent near the top of the engine or much of the old antifreeze will remain inside. If your engine does not have such a vent you should install one.