rv antifreeze after manual draining or not?

[scottb7]

After manually draining per manuals, is it really worth the effort to pour in the pink rv antifreeze? If you suck it in you won't get it everywhere due to thermostat. If you pour it in you can get it everywhere, but the only reason would be to avoid corrosion. But do we know it really does avoid corrosion, and would there be any, anyway?

Thoughts?

[Quinner]

At $4 a gallon or roughly $20 it is very cheap insurance that even the slightest amount of residual water will not be a freeze issue. BTW, if using the draw in method, cold stat will still allow flow into block so that is not an issue.

[Ricky95-196]

At $4 a gallon or roughly $20 it is very cheap insurance that even the slightest amount of residual water will not be a freeze issue. BTW, if using the draw in method, cold stat will still allow flow into block so that is not an issue.

Could you explain the "draw in method" and how it still gets into the block when t stat is cold please.
I warm engine on garden hose until thermostat opens then quickly hook up anti freeze line and pump at least 5 gallons through. This has seemed fo work for me. Is there a better method??? Thanks for any advice!!!

[Quinner]

As I understand it the TStat is there to regulate flow and the exiting of water, regardless of whether the TS is open or closed water WILL enter the block.

Ricky, your method may work but is very risky particularly if using RV A/F, there is a chance you're A/F could become diluted and lose some of its freeze protection.

The best/safest method is to drain all water from the raw water system, as a secondary measure of safety you then can draw in the A/F of choice into the completely drained system, simplest way is running the engine sucking or drawing in the A/F.

[scottb7]

This site has a really nice page where you can scroll down and see moving arrows for water flow. You can actually click on "thermostat open" and "thermostat closed" to see water flow difference.

http://www.boatinghowto.com/content/...tems-work-240/

That being said I am unsure if it exactly represents our boats. Agreed water DOES go through the block when thermostat is closed but how it goes through exhaust manifold will obviously depend on the thermostat.

So drawing in will with thermostat closed not get both manifolds in their entirety.

I am kind of leaning toward manual draining then draw in rv antifreeze. And granted it is only a few bucks $15 ($3 x 5 gallons) but I still think the question of if the rv antifreeze really prevents corrosion is up for debate. If there is no corrosion protection or if is unnecessary I would skip it, myself.

[jmo]

As part of my winterization process after fully draining all of the water out, I disconnect one of the hoses that goes from the thermostat housing to the manifold and pour AF directly into the hose towards the housing which fills the block. I leave the drain plugs on the block loose so I can confirm AF is making it in there. After that I fill the heater by pouring it as well and then I am done.

JMO

[Quinner]

That being said I am unsure if it exactly represents our boats. Agreed water DOES go through the block when thermostat is closed but how it goes through exhaust manifold will obviously depend on the thermostat.

Typical modern PCM with open/raw water cooling are all pretty typical, exhaust manifolds are the exit point so regardless of TS position the fluid is headed that way.

So drawing in will with thermostat closed not get both manifolds in their entirety.

TS open or closed, does not matter, if you draw in enough A/F it will eventually start dumping out via the Manifolds.

I am kind of leaning toward manual draining then draw in rv antifreeze. And granted it is only a few bucks $15 ($3 x 5 gallons) but I still think the question of if the rv antifreeze really prevents corrosion is up for debate. If there is no corrosion protection or if is unnecessary I would skip it, myself.

Draining all the water is key, adding via pour in is fine, IMO drawing in is the most failsafe method, yes you will use an extra gallon or 2 but really, that's about $8 to ensure you will not have any issues come spring.

No idea if the Pink stuff is anti-corrosive, does not claim to be on the label, probably no worse than the other 8 months there is just water in there.

[slob02]

I drain my blocks and everything.......I draw 3 gallons of antifreeze through a cold motor. The antifreeze will completely fill the block and even drip out of the exhaust. T-stat will not matter.

[jsta281]

As others have mentioned, I opened all the drain plugs and disconnected the various raw water hoses buttoned everything back up and then sucked in 4-5 gallons of pink RV anti freeze up the inlet hose. (until it started spurting out the exhaust pipe.)

I live in Utah with multiple days were it does not get above freezing and single digits at night. No problems.

If as you say, the closed T stat is blocking the AF from entering the block and manifolds, then where is the 5 gallons of pink RV fluid going?


Edit I have a closed cooling system so I do not speak directly to some other system. that said, my brother in law does not have a closed system, and uses the same procedure without issue.

[Jono]

i've never used anti freeze. I've been doing it for a decade, and it gets to minus 80 for 6 months where i'm at. I don't see the benefit, and I also don't see it as being cheap insurance. Its actually more of a risk if you don't do it properly. I can keep going....its more work, more money, more pollution, and more of a pain in the ***.
As long as your drain plugs are pulled you have zero worries. The only way a block will crack is if the frozen expanding water has nowhere to go. Just like a beer you forgot to take out of the freezer. If there is a tiny amount of water leftover in a passage or something, its a non issue as there is so much room for expansion. Even if you left half a beer in a bottle, corked it and froze it, it would still be there for you enjoy for breakfast someday without having the bottle crack.

[scottb7]

I agree with above. I am no longer doing the rv antifreeze after draining. Additionally regarding post #9. No one is saying closed thermostat keeps fluid from going thru block. Review post#5 with link. I think thermostat changes flow thru exhaust manifolds.