Winterizing: Prestone vs RV antifreeze

[Evinrude Boater]

Re: Winterizing: Prestone vs RV antifreeze

Too bad they don't have an air valve somewhere so one could blow air through the system like plumbing at the cottage.

 

[northernmerc]

Re: Winterizing: Prestone vs RV antifreeze

My usual procedure on the 4.3 litre Mercruiser is to pull the plugs on each side of the block, undo all the hoses on the block and manifolds and drain everything well. I also make sure that the leg is vertical, to allow it to drain. Then I put the plugs back in, reconnect the hoses, and pour in a couple of gallons of pink RV antifreeze until it starts to come out of the leg. Then I hit the key and turn over the water pump for a few seconds. This has worked well for nearly two decades.

In the last year or two, I became aware that there are two types of RV anti-freeze. Someone told me not to use the cheap stuff that people pour down the drains of their RVs - that there is a special anti-freeze that is better to use in boats. Does anyone know anything about this? Or is the cheap stuff OK to use?

 

[proxyx]

Re: Winterizing: Prestone vs RV antifreeze

the cheap stuff is propylene glycol (plumbing or RV antifreeze) mixed with some alcohol, thickens in low temp and does not solidify, doesn't change volume (won't burst), non toxic as opposed to ethylene glycol (automotive AF)

"Winterizes boats, recreational vehicles, seasonal homes, septic tanks, swimming pools filtration and heating systems

Burst protection to -50?C"
... what is probably more then -1000?F, haha

 

[Lou C]

Re: Winterizing: Prestone vs RV antifreeze

I do the rod it out...drain...back fill with the best -100 AF with corrosion inhibitor method...I do think that filling the engine with AF with corrosion inhibitors helps reduce the formation of rust over the winter because rust...is iron oxide....iron+oxygen in the air helped along by moisture.....you eliminate the air...and the oxygen...and you slow down the rusting process...the same reasoning behind spraying trailer springs and ubolts with Corrosion X....you put a barrier between the iron and the oxygen...and you get a LOT less rust...

My trailer springs and ubolts were all replaced 4-5 seasons ago...none has any rust still...corrosion prevention and reduction is about keeping oxygen away from iron...whether you use paint...Corrosxion X or antifreeze....

If AF wasn't good for engines....you could still run alcohol based solutions like they did in the old days....and for sure any engine manufacturer would tell you their cast iron engines were really designed to be full of antifreeze not just water as is done with a raw water cooled engine...so I think that using AF does slow down the process.....
I replaced a thermo housing in 2003 and have been storing this engine this way since then...and there is just surface rust inside...no large flaking corrosion which is what cast iron looks like after running salt water through it for a while....

 

[Chuck2001]

Re: Winterizing: Prestone vs RV antifreeze

For 20 years I run RV antifreeze through my seawater inlet until it runs out exhaust. Fog it down and maybe drain block, not always just accordding how I feel. I let fresh water run through for about 15 mins before I do this. I live in SC, not harsh winters but does get down to single digits sometimes, but boat is in enclosed garage. never had any problems.

The funny thing, I ask the boat dealership about 15 years agao about doing it this way and they laughed and said thats ludicrious. The next year they had a vat and backed the foot into it and did the same thing. As long as you maintain our boat properly, you can save money doing it your self.

 

[stonyloam]

Re: Winterizing: Prestone vs RV antifreeze

I've read various posts about using RV antifreeze to winterize the engine but I also read it doesn't contain corrosion inhibitors. Wouldn't it be better to use automotive antifreeze then drain and flush in the spring?

As I recall my basic chemistry, neither does lake water, and that is in there all summer. The safe bet is get ALL of the water out, and if you feel you must use antifreeze, go with the safe non-toxic RV type. Even a few drops of automotive antifreeze on the driveway can be bad news for the local pets.

 

[SuperNova]

Re: Winterizing: Prestone vs RV antifreeze

.... and blocks the water's exit! Anyone else 'been there, done that'?
Do I hear an AMEN!

Hebby Jebby, yeah!! Amen brother!! Back when I was young and dumb...etc I kiiled my first I/O by removing the drainplugs and NOT reaming out the holes....thought I got all the water out.....plugs were out right? ....Had to put new engine and manifolds in in spring. When I hooked up for first start, my engine bay look like a friggin' lawn sprinkler. Only gotta teach this boy once!! Ain't broke a block or manifold since....as stated so aptly by Bond-o "Air don't freeze" so I make darn sure all the water is out!

 

[Lou C]

Re: Winterizing: Prestone vs RV antifreeze

The RV stuff for winterizing water systems doesn't have corrosion inhibitors but the more expensive stuff for engine systems does....if you look on the container...but your first priority when winterizing is always get the water out...first....the AF is really just optional...if you want to minimize corrosion.
I feel that those kits they sell at West Marine and other places...should have a warning on them....that they are not appropriate for a raw water cooled engine...yet I see them being sold all the time...and people don't read manuals so they don't realize the risk in using them....

and for the first timers doing this...get you manual...get a nice long wood screw or real thin screwdriver...and keep in mind...a V-6 or V-8 block holds at least between 2 and 2 1/2 gallons of water..if not a little more....if you're not seeing a lot...something's blocked up...manifolds hold a fair amount of water too...as does the big hose on the front circulation pump...remove it a the bottom when draining the block....when I backfill my little V-6 with AF...it takes close to 4 gallons to fill both the block and manifolds and a little to fill the raw water intake hose to after it gets drained down in the bilge...

 

[skargo]

Re: Winterizing: Prestone vs RV antifreeze

Not sure why everyone says the RV antifreeze doesn't have inhibitors.

Read the label.