View Full Version : Winterizing Question

10-07-2008, 12:39 PM
I have a 93 S&S with the Lt-1 motor is it ok to suck antifreeze up throuth the intake and store the boat? This is all I have ever done with any other boat I have owned. I am pretty new to this boat and have heard that the antifreeze may be bad for the aluminum heads? not sure what to do, I live in Wisconsin and don't want to have problems in the spring, I usually use the -50 Rv antifreeze with the rust inhibitor. Thanks for you help with my problem, I really appreciate your advice with this matter.


10-07-2008, 01:53 PM
Sierra antifreeze is propylene glycol with no phosphate corrosion inhibitors. You could certainly pickle your boat with that. The problem with phosphates in antifreeze is "hot spot corrosion", where in the presence of high heat, there can be potentially significant erosion of aluminum at the exhaust ports. Obviously, if we're talking storage there is no engine heat, so likely using RV antifreeze with phosphates is fine, but if you're worried about it, go get some Sierra antifreeze from your local auto dealer.

10-08-2008, 07:45 AM
Thanks for your help BigMac, I will look for some Sierra antifreeze and finnish my winterizing.

10-08-2008, 08:29 AM
Thanks for your help BigMac, I will look for some Sierra antifreeze and finnish my winterizing.

In the event you can't find Sierra, you'll be looking for a phosphate-free propylene glycol-based antifreeze. It should be labeled as "environmentally safe" or "low toxicity", or something like that.

Note that the problem with phosphate is corrosion of aluminum at high heat - the kind of heat you get at the exhaust ports of the heads. It's not inherently damaging to aluminum. Phosphate-containing corrosion inhibitors have been used in automobile cooling systems for many decades, and when's the last time you heard of a coolant radiator that wasn't made of aluminum?

Anyway, I'm certainly not convinced that phosphates are a problem of ANY kind when they're in propylene glycol instead of ethylene glycol, since EG will actually accelerate the heat-aluminum-phospate reaction process whereas propylene glycol will not. And if it's used for storage only, and not while the engine is running....I just don't see the problem.

09-09-2009, 10:50 AM
I've never added any anti freeze to my LT-1. Drain the block, petcock and water temp sender, drain the exhaust manifolds, take shower lines off, blow them out, blow out the heater core lines. Disconnect several of the other water lines at the front of the engine and drain them (any ones that might have a bend that collects water). I always leave everything disconnected/open at least for a month or so or even until spring with the thought that evaporation will get any little residual water.
Done this for 6yrs now and though it's garaged 99% of the time in the winter, it's been out a few times that somthing would have froze and cracked for sure if there was any water left.

09-09-2009, 08:19 PM
Take a look at my posting titled beware of the petcock. take the plug out all together to insure tht the water drains. In my case I opened the pet **** some what came out and then it stopped, there was rust that clogged the petcock. Do yourself a favor and get rid of it