Putting RV Antifreeze in engine

[pmellis]

I was wondering what the best method is for putting RV antifreeze into the raw water cooling system on my G23. My dealer suggested adding a Perko flush valve right after the raw water intake and I like that idea, but when I went on Amazon to order it I saw some bad reviews. Some people said they almost sank their boats because the flush assembly broke apart. That made me wonder what the factory Nautique fresh water flush looks like. I guess I should've ordered that option. Anyone else put RV antifreeze in their engines?

[jhersey29]

How would you rate the following? Ease of installation, cost, protection, mess, environmentally friendly, etc.

I personally use the drain water first then suck in 5-7 gallons of rv antifreeze and drain it all out. It is messy, it is probably not environmentally friendly since its still a chemical and wasted plastic jugs, it is not the cheapest route. I do it because it is easy. Taking out the thermostat and pooring in is probably the best for cost, the environment, and protection. I do like the suck in method since the water.pump forces the anti freeze through the engine instead of relying on gravity but worry the thermostat may not open. I drain it just to make sure the pink comes out of the block at the drain holes. Some people just do the drain only but I think that is crazy. There is about a quart or more of water in an engine even after drained. Well at least on the ford 351 there is. It spilled out when I took the engine out for a rebuild last winter. Anyone doing that hasn't taken an engine out of a boat to see how much water is actually left in the engine.
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[Quinner]

You have a couple options on adding a flush point, the Perko being one of them. You could also make your own Tee for about $20 in parts from the local Hardware store. If your intake hose is reasonably accessible you could simply pull it and add your Tee/Perko temporarily just to do your flush, then re-attach intake when complete.
Regardless of how you draw in the antifreeze be sure and drain all the water first.

[kend]

I put the RV antifreeze in through the thermostat cap; a bit of a hassle but not that big of a deal. I always put the antifreeze in because of rust; engine parts that have been exposed to high heat rust easily and the antifreeze has rust inhibitors

[Quinner]

Pretty sure the OP has a closed cooling system, so T-Stat is not part of the drain/winterize equation.

Ken, I always thought the same about the RV antifreeze being anti corrosive until recently a post indicating otherwise. Not certain if that info was accurate and have not read the label on the bottles or researched beyond that, did get me wondering though???

[scottb7]

I do drain only. "Some people just do the drain only but I think that is crazy." is said by a person that pours in rv antifreeze and then drains it back out. Not making fun of you but that was entertaining.

The mfgr manual gives drain points for a reason. Cause that is all you have to do. It is not about getting every drop of water out. It is about getting water out of places that don't have room to expand.

I used to drain water, then suck in rv antifreeze, and leave in all off season. But last few years I just drain.

Corrosive or not...no one on this forum will live long enough, or the person they give/sell their boat to will not live long enough to have a problem due to not back filling with rv anti freeze.

Do what you want, freedom is awesome. I just thought I needed to push back on all this drain theory on this thread.

Ps...you know what I do do? I give ski safe a few extra bucks each year so that if my engine cracks i get a new one.

[swankster]

On the 2013-15 450 the engine should already have antifreeze in it. Raw water is used to cool the manifolds, transmission and heat exchanger. Like Scott, I just drain mine, partially because it is only winterized for 4 months and partially because I don't think it is worth the expense and hassle of adding the antifreeze. 6 plugs, one hose and strainer .... done. I keep sta-bil marine in it year round.

[vision]

I also just drain my CES 450. But I also run my engine for 15 seconds post draining to get more water out of the impeller pump and the hose from the straner to the pump. I have had water pool in the hose due to gravity and freeze even after draining the tranny, manifold, strainer, and manifolds.

[scottb7]

I remove the impeller pump and store for the winter, which is easy on my 343. And the transmission cooler has a plug which is at lowest point between strainer and impeller pump.

[Jeb1974]

If you look at the RV antifreeze bottle it usually says not for marine engine use. I used it on my old boat but a buddy who was a marine mechanic said it would cause seals to deteriorate. Apparently the Merc or Starbrite is good for this application. (I used starbrite this year.)

Instead of putting in a valve, I just disconnected the intake and connected my bucket with a hose to it which was quick. One thing that I found is that the G takes a lot of antifreeze. My last boat with a Merc needed less than 4 gallons but the G took 6 before it started coming out the exhaust.

[pokesgrad02]

I remove the impeller pump and store for the winter, which is easy on my 343. And the transmission cooler has a plug which is at lowest point between strainer and impeller pump.

I have heard of a few people removing the impeller for winter. Thoughts? Mine was replaced when the engine was winterized before delivery. Should I pull the impeller?

[MI-skier]

I have heard of a few people removing the impeller for winter. Thoughts? Mine was replaced when the engine was winterized before delivery. Should I pull the impeller?

I always take mine out. Otherwise it could take the "D" shape after not spinning for 5 months.
I have no data if this helps or not but it feels better...
I usually get 2-4 years per impeller. Replace when the base of the blades starts to show any cracking whatsoever.

[scottb7]

Honestly, I would not pull it if already winterized properly. I do it because it is part of my process. I pop off the serpentine belt, pull the pump body off inspect the impeller and save the impeller and pump body on my workbench for the next year. That way I know I got all the water out of the pump. I don't actually really believe that it could take the D shape. I should take an old impeller someday and put it under a brick for 6 months and see what happens. lol.

[pmellis]

I also just drain my CES 450. But I also run my engine for 15 seconds post draining to get more water out of the impeller pump and the hose from the straner to the pump. I have had water pool in the hose due to gravity and freeze even after draining the tranny, manifold, strainer, and manifolds.

My dealer told me to do this too. Pull all the plugs and run it for 10-15 seconds to push out remaining water. Then put plugs back in. They don't put in antifreeze as part of their process. Seems like just pulling the intake hose is easiest and safest way to get antifreeze into the raw water system.

[scottb7]

That makes absolutely no sense. If you do want to run it for 10-15 seconds. Which is not necessary, you certainly don't need to pull the plugs and put them back in...