winterizing i/o

kulle

Petty Officer 1st Class
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May 23, 2018
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294
Does anyone know about how much antifreeze i would need to winterize a merc 4.3 v6?
 

harringtondav

Commander
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May 26, 2018
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2,480
First you need to drain the block, manifolds, water pump hose and steering cooler.

I used to refill the block with antifreeze thru the pipe plug below the thermostat hsg until it flowed out the exhaust. One gallon plus a little more
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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none

you drain the block, heads, hoses/PS cooler and manifolds to winterize.

then if antifreeze makes you warm and fuzzy, you pour it into the system at the thermostat housing with a funnel.
 

kulle

Petty Officer 1st Class
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May 23, 2018
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294
none?? so drained properly you are suggesting you dont need to add any AF? i have the manual and found where the drain points are, but thought you still needed to pump some through while running until it comes out of exhaust. when i got the boat the guy gave me his winterizing kit with the dual valve -run on muffs to temp, then switch valve to AF.
 

Lou C

Supreme Mariner
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Nov 10, 2002
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13,424
Easiest way is to:
after complete draining and probing all drain holes

disconnect the lower end of the big hose at front circulating pump, this drains a good amount of water. Then after it's done draining re-connect at the bottom end. Next disconnect it at the thermostat housing (top end of hose) and fill the engine with -100 marine AF till AF comes out the thermostat housing neck. No need to remove thermostat. Re-connect hose you are done. You can fill the manifolds and the raw water intake hose as well. If I recall the engine + manifolds take about 4.5 gallons.
 

Bt Doctur

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Aug 29, 2004
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19,454
when i got the boat the guy gave me his winterizing kit with the dual valve -run on muffs to temp, then switch valve to AF.
and to what? Call him next year to replace the motor?
 
Joined
Jul 24, 2015
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Didn't drain the intake manifold on a 4.3 Vortec, after 9 years it froze and cracked. Years ago didn't probe the drain holes and cracked the exhaust manifolds, fixed them with JB weld. This year I changed the exhaust manifolds because of water in the oil but it was the intake manifold. Now dealing with overheating again,..Just taking some picture now and will start a new thread if I don't find the problem.
 

Rick Stephens

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Aug 13, 2013
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6,118
Didn't drain the intake manifold on a 4.3 Vortec, after 9 years it froze and cracked. Years ago didn't probe the drain holes and cracked the exhaust manifolds, fixed them with JB weld. This year I changed the exhaust manifolds because of water in the oil but it was the intake manifold. Now dealing with overheating again,..Just taking some picture now and will start a new thread if I don't find the problem.

I would suggest you start your own thread.
 

Scott Danforth

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none?? so drained properly you are suggesting you dont need to add any AF? i have the manual and found where the drain points are, but thought you still needed to pump some through while running until it comes out of exhaust. when i got the boat the guy gave me his winterizing kit with the dual valve -run on muffs to temp, then switch valve to AF.

nope, not needed, not in the factory manual. there is a sidebar note that says AFTER DRAINING adding AF is optional for long-term storage if you want.... it must be added thru the t-stat housing with a funnel

hence the reason that none is needed.

trying to suck thru the muffs will be fastest way to a cracked block.... guaranteed.

BTW, the cheepy pink stuff AF will freeze at 20 degrees. Air freezes at -461
 

Oshkosh1

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Jun 8, 2009
Messages
968
I use nothing. I simply drain the block, drain the manifolds/risers, remove the PS pump and pull the TStat housing and blow back through with compressed air just to ensure all the water is out. Smear the threads of the plugs with grease, re-install and good to go through the winter up here in the "Frozen Tundra" of NE Wisconsin. We easily see -20 so I don't trust any of those pink slushy mixes...
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
I use nothing. I simply drain the block, drain the manifolds/risers, remove the PS pump and pull the TStat housing and blow back through with compressed air just to ensure all the water is out. Smear the threads of the plugs with grease, re-install and good to go through the winter up here in the "Frozen Tundra" of NE Wisconsin. We easily see -20 so I don't trust any of those pink slushy mixes...

I don't even do that... I just park the boat up, drop the drive down and walk away. We rarely see temperatures below 3 degrees, so nothing freezes.

Chris...... ;)
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
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I don't even do that... I just park the boat up, drop the drive down and walk away. We rarely see temperatures below 3 degrees, so nothing freezes.

Chris...... ;)

I think the US is the only place in the world left where water freezes at 32' ;)
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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the other two non-metric countries are Burma and Liberia
 

kulle

Petty Officer 1st Class
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May 23, 2018
Messages
294
well i'll run through the manual and drain what it says..sounds like that should be sufficient. is it recommended to pull off/drain the fuel/water filter? I guess it cant hurt..thanks for everyones replies...maybe i'll get to use the boat for more than 1.75 hours next season.
 
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