yes another winterizing question!!

M

masilobes

Member
Nov 2, 2010
81
buzzards bay ma
Boat Info
Kayla B
Engines
twin 350 mag mpi
when using one of those winterizing kits (jug with a tee and antifreeze) they show you heating the motor on water through the muffs and when it reaches operating temp switching to the antifreeze through the muffs. would there be any harm in draining the block first then antifreeze through the muffs. basicly would i be doing harm if im running the motor with no water in it until it fills with just antifreeze?
 
No harm at all, in fact it's the right way to do it. Drain both the block and manifolds.
 
When I winterize my friend's out drive, I attach a tee on the muff. I attach a water hose on 1/2 half of the tee and the AF jug on the other the other half. I open the water hose and run the engine up to operating temperature so that the thermostat is open. Without stopping the engine, I open the AF jug tap and close the garden hose tap and run it until there is solid green coming out. Shut engine off, remove muffs and open engine drain plugs and leave them open for the winter.
 
either way just work fast if you're going to drain the block so your t-stat doesn't close. I used to go through the trouble of draining the block but always felt like there was a clock ticking in my head while I would open up plugs and watch the water run out.
 
maybe its me but the muff way sucked!! antifreeze was going somewhere, mostly on the ground and not enough was going to the block. next thing the high temp alarm went off so i fogged it and shut it down and added af through the thermistat hoses. i would say the block was half full and the risers were dry. question i never really looked at the hoses that go to the risers and manifolds, they are really low. i have always heard you will know when they are filled when you hear af coming out the exhaust, but none came out the exhaust only the t stat housing. is this right?
 
masilobes said:
maybe its me but the muff way sucked!! antifreeze was going somewhere, mostly on the ground and not enough was going to the block. next thing the high temp alarm went off so i fogged it and shut it down and added af through the thermistat hoses. i would say the block was half full and the risers were dry. question i never really looked at the hoses that go to the risers and manifolds, they are really low. i have always heard you will know when they are filled when you hear af coming out the exhaust, but none came out the exhaust only the t stat housing. is this right?
Click to expand...

My risers are high also. I don't get any AF coming out the drive either. So, I drain the blocks and mani's. Pull the big hose off the T-stat housing and pour AF until the liquid coming out of the t-stat housing is really purple (I see clear water for about a 1/3 of a gal. and then it is pure purple). Once it is really purple I put a cup under the t-stat houseing to catch the fluid and then check it with a A/F tester to make sure it is pure A/F.
 
Agreed - drain block and manifolds before adding the AF.
You are correct that using this method always runs the risk of leaving the block dry if the tstat doesn't reopen.
Go online and look up the cooling system for your engine. Analyzing the flow paths will allow you to understand what will get filled, and how.
For instance, on a 350Mag the flow path is from the inlet on the lower unit to the raw water pump, to PS cooler then to cool fuel block, then to distribution block, sending it to manifolds and to water pump housing, then to tstat housing, to risers and IF tstat is open - to block.
So for me, running on muffs will get everything for certain, except maybe the block based on tstat position.
So my safest method if using the muffs - drain everything. Run on muffs with AF and fog (correct way based on fuel system). When finished, pull main hose off tstat housing and check for AF. Pour AF into hose until it comes out the tsat assembly as pure AF.

Many will suggest draining it all at the end - different discussion.

This year I invested $5 in a baby pool, and $29 in a submersible pump. I put 6 gallon AF in the pool and placed it under the lower unit, then put the muffs on the pump and put it in the pool. Plugged in and started (already drained everything first). Ran it until temp was reached (165). I pulled the main hose and everything including the block was pure AF. Better use of the $35 instead of the premade gravity system you buy online. No timing issues this way.
 
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So the kiddie pool is just to catch the spilling/ejected antifreeze and pump it back up?
Also, what kind of AF do you use in the engine block?

paulswagelock said:
Agreed - drain block and manifolds before adding the AF.
You are correct that using this method always runs the risk of leaving the block dry if the tstat doesn't reopen.
Go online and look up the cooling system for your engine. Analyzing the flow paths will allow you to understand what will get filled, and how.
For instance, on a 350Mag the flow path is from the inlet on the lower unit to the raw water pump, to PS cooler then to cool fuel block, then to distribution block, sending it to manifolds and to water pump housing, then to tstat housing, to risers and IF tstat is open - to block.
So for me, running on muffs will get everything for certain, except maybe the block based on tstat position.
So my safest method if using the muffs - drain everything. Run on muffs with AF and fog (correct way based on fuel system). When finished, pull main hose off tstat housing and check for AF. Pour AF into hose until it comes out the tsat assembly as pure AF.

Many will suggest draining it all at the end - different discussion.

This year I invested $5 in a baby pool, and $29 in a submersible pump. I put 6 gallon AF in the pool and placed it under the lower unit, then put the muffs on the pump and put it in the pool. Plugged in and started (already drained everything first). Ran it until temp was reached (165). I pulled the main hose and everything including the block was pure AF. Better use of the $35 instead of the premade gravity system you buy online. No timing issues this way.
Click to expand...
 
paulswagelock said:
Agreed - drain block and manifolds before adding the AF.
For instance, on a 350Mag the flow path is from the inlet on the lower unit to the raw water pump, to PS cooler then to cool fuel block, then to distribution block, sending it to manifolds and to water pump housing, then to tstat housing, to risers and IF tstat is open - to block.
So for me, running on muffs will get everything for certain, except maybe the block based on tstat position.
Click to expand...

I could be wrong (won't be the first time) but cooling water is always directed through the block regardless of the position of the thermostat. If the thermostat is closed the water just circulates in the block until it reaches the temperature that will operate the thermostat at which time it opens to allow cool water to flow into the block and the heated water to circulate and cool. When the pink antifreeze is pulled in through the muffs it goes through the raw water pump to the thermostat housing which distributes the raw water to the manifolds and the circulating water pump which fills the block.
If I understand the flow correctly, if the thermostat is closed than only the outflow path from that point will remain dry and, if you choose, pink can be added directly.
I would appreciate it if I need to be corrected on this.
Bob
 
Following my flow path, a closed tstat would prevent water from leaving the block coolant loop. So, if full of water when on muffs, and tstat stays closed, still full of water. If empty first, water pump should push antifreeze in and recirculate it. The rest of the water goes around the water pump to the risers or exhaust manifolds depending on tstat position.

Here is a link to a picture with the flow paths:

http://www.mercruiserparts.com/images/COMMON/10115.png

Animated path:

http://www.boatinghowto.com/content.php?137-Marine-Cooling-System-Flow-Examples
 
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The only I felt safe in winerizing the 7.4 was to drain the block and manifolds. Next we removed the
thermostat and ran the antifreeze into the engine. I don't trust the thermostat to stay open and in PA you don't guess on winterization.







paulswagelock said:
Following my flow path, a closed tstat would prevent water from leaving the block coolant loop. So, if full of water when on muffs, and tstat stays closed, still full of water. If empty first, water pump should push antifreeze in and recirculate it. The rest of the water goes around the water pump to the risers or exhaust manifolds depending on tstat position.

Here is a link to a picture with the flow paths:

http://www.mercruiserparts.com/images/COMMON/10115.png

Animated path:

http://www.boatinghowto.com/content.php?137-Marine-Cooling-System-Flow-Examples
Click to expand...
 
paulswagelock said:
If empty first, water pump should push antifreeze in and recirculate it. The rest of the water goes around the water pump to the risers or exhaust manifolds depending on tstat position.
Click to expand...

That is how I understand it but not quite how I explained it. Thank you for clarifying that the block should be emptied first. I drain the block, manifolds and hot water tank heat exchanger and then draw up pink antifreeze through the muffs. System is full once it starts coming back out through the exhaust.
 
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