Winterizing your boat: Can I use RV antifreeze?

[2porscheguy]

PPOT guys and gals please help me out! I'm planning on winterizing my boat myself this time, as I'm freekin' tired of paying $400.00 plus to have it done by the local marine shops "by appointment only" here in Calgary. I've done some research and I've heard yes and no with regards to using plain old Propylene Glycol -40 degree C RV antifreeze in the engine for winter protection against freezing. I understand that the true -60F to -100F Marine antifreeze has a rust inhibitor....what is it and do I trully need it?

It seems that the local marine shops won't sell me the stuff as they would obviously prefer to perform the service themselves for $$$....surprise, surprise! My Campion has the 4.3L GL Volvo Penta btw.

I, as always, greatly value your opinions!

Cheers!

Alex

[dhoward]

RV antifreeze is fine.
I've used it for years no problem. Do motor and all of the plumbing

[2porscheguy]

dhoward, what type of boat and marine engine have you used it on? You've had no issues with rust? How cold does it get in your area?

Alex

[Hard-Deck]

A boat is an RV, use it.

[Black968]

From the way you are talking it sounds like an inboard. Buy a set of muffs and a 10 l pail of RV Boat antifreeze. It is usually pink in color, costs about 12-15 dollars at Canadian Tire. Also drop the lower unit gear oil as it is possible for water to migrate in and split the lower unit. Leave it empty until spring or fill it up with an approved oil for your unit. It is best if you buy a pump to fill it. There are two screws (upper and lower) that will have to be removed. Check out video.

How to Winterize a Mercruiser - YouTube

[2porscheguy]

Black968 yes, it's a Volvo stern drive. I've viewed the Youtube clip and others like it. WestMarine also has a great 5 part one too...in all cases though, they've used the official Marine antifreeze and didn't mention the regular RV stuff.

[onewhippedpuppy]

iboats is a great forum for boats, just FYI. Rv antifreeze should be fine, though many recommend just thoroughly draining the system and leaving it dry.

[mudman]

I've always used RV antifreeze, the pink stuff. We see winter temps well below zero f, and as for the rust issue, it's a boat. Does your lake water have rust inhibitor in it? I have a tournament ski boat with a merc sbc inboard and have always used the pink stuff since new, never any problems.

[lm6y]

Yep, it will work fine. Your engine block will have drains, and most I've seen have petcocks on the drains. Open these up to remove as much water as you can, first. We always ran ours with the muffs on the RV antifreeze, recirculating it while we "fogged" the engine with WD40 to keep the cylinders from rusting. Add Stabil to the fuel tank, and fill it up. With plastic tanks, I'm not sure you have to do this though, our fuel tank was steel, and this kept it from rusting. If it gets really cold, put a 60 watt light bulb in the engine compartment for a little heat.

Like many have said, check the boat forums. there's lots of good info there.

[intakexhaust]

Originally Posted by lm6y

Yep, it will work fine. Your engine block will have drains, and most I've seen have petcocks on the drains. Open these up to remove as much water as you can, first. We always ran ours with the muffs on the RV antifreeze, recirculating it while we "fogged" the engine with WD40 to keep the cylinders from rusting. Add Stabil to the fuel tank, and fill it up. With plastic tanks, I'm not sure you have to do this though, our fuel tank was steel, and this kept it from rusting. If it gets really cold, put a 60 watt light bulb in the engine compartment for a little heat.

Like many have said, check the boat forums. there's lots of good info there.

Never liked using Stabil and for years with O.B.'s, the winterizing simply involved while running the engine, lower unit sitting in large tub / drum with a weak ratio of anti-freeze glycol / water, pull the supply fuel line or (shut-off valve) and let it run dry to shut itself off. Afterwards would drop the lower unit oil, leave empty (make a tag attached to the unit - warning of empty). Pull spark plugs, squirt a slight shot of Sea-foam... don't over soak. Re-install plugs. Done

[2porscheguy]

Originally Posted by mudman

Does your lake water have rust inhibitor in it?

True Dat!!!

[dhoward]

(2)740 Volvo duoprops. down to -5 tops.
It's an open system so rust is always a problem, right?
We also plop one of those oil-filled radiator type heaters in the engine space.