Winterization question(s)....not how to do it

[badrano]

3) it is NOT NECESSARY to remove the stat to fill the engine with AF, the way you do it (doing it this way 15+ years) is:
drain from the block drains, poke holes, same with intake drain if you have it, then drain by removing bottom of hose as in #1 above. Then after it all drains, reconnect bottom of that hose. Replace all the drain plugs, put a bit of Permatex Aviation on the threads of metal plugs. Disconnect the top end of the big hose. Now fill via that hose till the engine is full, it will take quite a bit and when AF spurts out of the thermo housing you are done. Re-connect hose no need to remove the thermostat.

I'm going to ask the stupid question. I can understand filling AF from the hose leading to the circ pump, but if the thermostat is shut, how will AF flow out of the t-stat housing so that you know the engine block is full?

 

[Lou C]

On the Volvo/OMC style thermostat housings the stat, is higher up inside the housing than the outlet for the circulating pump, and the Merc style ones are similar, so the stat is not put into the opening in the intake manifold as it would be on an auto application, it is higher up inside. On the Volvo/OMC style there is a rubber ring that holds it there, on the Merc style there is a plastic spacer.

These stat housings for raw water cooling are totally different than what is used in an auto application. On a cold engine, the stat is closed but cold water flows in from the impeller hose and is shunted to the exhaust manifolds. When the stat is closed, water is kept in the block until it gets hot enough to open, then the stat allows hot water to flow out of the engine, out through the exhaust manifold. Cool water delivered in from the impeller is sucked into that big hose by the suction of the circulating pump once the stat opens.

 

[H20Rat]

1) did you remove the bottom end of the big hose that connects the thermo housing and the circulating pump? If not this holds a lot of water, and it should be drained at winterization or else your water pump will freeze up and crack.
2) newer (Vortec and up ie 96& newer) have a plug on the front lower left corner of the intake manifold, this needs to be drained as well

Yep, been winterizing boats for quite a while, longer than 15 years. This particular engine is a 2002 vortec, all 5 plugs + hose removed, holes poked with long wires, etc... There was still quite a bit of water left in there after all the previous steps. I've used pink AF for many years, and it gets slushy at low temps, but haven't had it freeze solid. (record low for where my boat is parked is -45f)

 

[Lou C]

Wow -45 is something we would never see....zero...is about the coldest we get because we are surrounded with salt water...
In your application if I'd for sure use the -100.

 

[HT32BSX115]

3) it is NOT NECESSARY to remove the stat to fill the engine with AF, the way you do it (doing it this way 15+ years) is:

Only reason I mentioned removing the stat is that this is the "generic" forum (not the OMC, Volvo, Merc, etc there's clearly plumbing differences that would certainly not require removing the stat in every case........)

Many people here don't carefully read every message fully and possibly only see "Not Necessary to remove stat etc etc" so I was trying to do a one size fits all suggestion.

I don't think anyone will ever go wrong removing it even though it may not be required in every case.........

Bottom line, if you drain everything thoroughly, even pouring in AF is not required at all.....but I digress!

Some famous guy once said "AIR DON'T FREEZE"
(he also said "ANY GREASE is ........." but there I go digressing again!!)

Cheers,

Rick

 

[badrano]

On the Volvo/OMC style thermostat housings the stat, is higher up inside the housing than the outlet for the circulating pump, and the Merc style ones are similar, so the stat is not put into the opening in the intake manifold as it would be on an auto application, it is higher up inside. On the Volvo/OMC style there is a rubber ring that holds it there, on the Merc style there is a plastic spacer.

These stat housings for raw water cooling are totally different than what is used in an auto application. On a cold engine, the stat is closed but cold water flows in from the impeller hose and is shunted to the exhaust manifolds. When the stat is closed, water is kept in the block until it gets hot enough to open, then the stat allows hot water to flow out of the engine, out through the exhaust manifold. Cool water delivered in from the impeller is sucked into that big hose by the suction of the circulating pump once the stat opens.

I see. I changed out the t-stat this weekend and I saw the plastic spacer. I should have taken the time to study the housing to how it all works.

Thanks Lou C

 

[Lou C]

True and one other reason if they have a raw water cooled engine is to clean out the rust flakes that will inevitably get into the stat and stop it from closing in which case it will only get up to 120*F, unless the flakes dislodge on their own...
Only downside to doing it is that if the last person who put the bolts in....didn't use a gasket sealer on the threads...they could break...although they are pretty beefy bolts....

 

[badrano]

Next dumb question...I think I missed a step....are you supposed to put gasket sealer on the bolts and gasket? When I changed the t-stat, I had the automotive mind set.

 

[Lou C]

Bolts yes but gasket Merc says no because of the little metal rivets...they need to make contact for the temp warning system to work

 

[badrano]

Bolts yes but gasket Merc says no because of the little metal rivets...they need to make contact for the temp warning system to work

Can I just pull the bolts back out and apply the sealer and then re-torque and not have to replace the gasket? The gasket just got put on this past weekend and the engine run in the driveway.

 

[Scott Danforth]

yes, you can pull the bolts out one at a time.