Should Engine Be Warm When Draining?

[isaacs]

When I winterize my boat (5L Alpha 1, Gen 2) I always warm the engine up before draining it. I figure this way the thermostat will be open after I replace the plugs and run AF from a five gallon jug with headphones through it resulting in the AF getting into the block. I use the pink RV antifreeze made by Stabil which contains no ethanol; I do this for corrosion protection over the winter.

My problem/question is, by the time I restart the engine to suck up the AF, the engine has cooled off a bit and I'm sure the thermostat has closed anyhow. Am I wasting my time and burning my fingers for nothing by warming it up in the first place? Does a small amount of coolant seep past the thermostat even when its closed?

For what it's worth, I've been doing this since the boat was new in 2002 and I get absolutely no rust or scale out of the drain holes; I must be doing something right!

 

[Scott Danforth]

if you drain, it doesnt matter. the thermostat is used as a mixing valve in most marine motors unless you have a heat exchanger and would slam shut the second your AF hit it anyway, and would have closed about a minute after you drained it. so for adding AF to a drained motor, no need to burn your fingers.

if you dont drain it, and you added AF, the AF would hit the t-stat, it would slam shut and bypass the block/heads and go straight out the exhaust.

you should warm it up to change the oil to make that part of your winterization easier.

 

[harringtondav]

My '96 4.3 has a pipe plug in the front of the intake manifold, left of the thermo hsg. This is a hot water feed for a cabin heater. When I used to add antifreeze, I removed this plug and funneled antifreeze in until I heard it splatter on the driveway out the exhaust bypass ports in the gimbal plate. After I did a full block drain, of course.

 

[shaw520]

(2) bolts to remove the TS housing and pour in till full,....that how I do it.

 

[achris]

(2) bolts to remove the TS housing and pour in till full,....that how I do it.

Open the drains, poke the holes, walk away... That's how I do it....

 

[shaw520]

Open the drains, poke the holes, walk away... That's how I do it....

Your lucky,..do that around here with a 20 yr old original engine and you'll end up with a crack $$$$

 

[achris]

Your lucky,..do that around here with a 20 yr old original engine and you'll end up with a crack $$$$

How so? What's left in the engine to freeze? Air? Yeah, maybe if the temperature gets down to -200C but at that temperature, even the best AF will have cracked your block long ago....

Air doesn't freeze, AF is a crap-shoot. NOTHING will convince me otherwise.

 

[shaw520]

How so? What's left in the engine to freeze? Air? Yeah, maybe if the temperature gets down to -200C but at that temperature, even the best AF will have cracked your block long ago....

Air doesn't freeze, AF is a crap-shoot. NOTHING will convince me otherwise.

Like I said , you've been lucky. By the way, how cold does it get in your neck of the woods?. But if your looking to give good advise,...should point out that just "poking the holes" is no guarantee that your entire engine is drained,...I know this from personal experience and no one will convince me other.

 

[achris]

......should point out that just "poking the holes" is no guarantee that your entire engine is drained,....

Ok, maybe I should have said 'poking the holes and making sure they fully drain'...

So, how can an empty block crack?

 

[shaw520]

,......if you have to "poke holes" to get that (1) jacket to drain,... what about the other (7) jackets on each side of the block,...and what about that clogged passage where the head meets the block and the gasket reduces down to a 1/4",... very common occurrence on older engines. Ive seen it on more than a few occasions.

 

[shaw520]

Its not the empty block that cracks,... its the one where the owner THINKS its empty that'll crack

 

[achris]

,......if you have to "poke holes" to get that (1) jacket to drain,... what about the other (7) jackets on each side of the block,...and what about that clogged passage where the head meets the block and the gasket reduces down to a 1/4",... very common occurrence on older engines. Ive seen it on more than a few occasions.

Oh, sorry, i see now... Water is so viscous it can't drain though a 1/4" hole.... What sort of water are you boating in?????

And I said holes, plural... Yes, each side of the engine block, and bottom of each manifold. I'm not stupid!

 

[shaw520]

Surely you're smarter than this Chris,...its not the water,..its the scale build up inside the raw water cooling jackets that clogs passages,...not allowing the water to drain.
The block drains are at the rear most water jacket on either side of the engine,... there are (7) more water jackets on each side of the block that are NOT accessible with a "poking" tool,....but be my guess and continue your procedures,.. I'll stick to mine

 

[QBhoy]

How so? What's left in the engine to freeze? Air? Yeah, maybe if the temperature gets down to -200C but at that temperature, even the best AF will have cracked your block long ago....

Air doesn't freeze, AF is a crap-shoot. NOTHING will convince me otherwise.

Chris
What about the flakes of corroded internals that you need to clear out the drains ? The last 20 odd years of doing this was enough to change my mind and AF fill every year with the most recent boat. 600 hours and 15 years old. Not a flake or bit of crud anywhere from drains. I check every year

 

[QBhoy]

Oh. I see a few have said this.

 

[isaacs]

Gee, I didn't mean to start an argument! You all make good points, thanks for the replies.

When I uncover in the spring, I'm going to open the plugs on the block and see if any AF made it down there past the closed thermostat.

As far as dumping AF into the thermostat housing, does that ensure that the exhaust manifolds are getting AF? That's where most of the corrosion occurred in my last boat.

 

[wahlejim]

Why wait til spring to check if AF got down there? Crack open the drain plug, drain a bit into a bag and throw it in the freezer This will tell you if you have achieved a ratio that holds in negative temperatures and doesn't freeze.

I think that even throughout the argument of AF or no AF, introducing it through the outdrive is a big no no. If you do introduce it, go through the thermostat housing, that is the general consensus. On my engine (Merc 228 305 block) The housing sits above the level of the exhaust manifold with a hose going directly to it. No reason they wouldn't fill up also

 

[achris]

Surely you're smarter than this Chris,...its not the water,..its the scale build up inside the raw water cooling jackets that clogs passages,...not allowing the water to drain.
The block drains are at the rear most water jacket on either side of the engine,... there are (7) more water jackets on each side of the block that are NOT accessible with a "poking" tool,....but be my guess and continue your procedures,.. I'll stick to mine

:facepalm:

You really should stop 'talking' now... Because your stupidity is on show for all to see...

 

[achris]

And I guess that means it's time to close this thread. It's gone on too long already and it's going nowhere.

Thread closed. End of discussion.

 

[shaw520]

When I uncover in the spring, I'm going to open the plugs on the block and see if any AF made it down there past the closed thermostat.

.

Lift the thermostat out then fill block w/AF,... It wont go past a closed stat therfore not getting into the block.