Prestone for head anti-freeze?

[transmitterdan]

PG may be cheaper but it eats up the seals in the toilet. So what is cheap now becomes not so cheap later,

[hellosailor]

Go to an RV store, or any chain selling antifreeze (usually pink) that is designed for RV waste systems. I'm sure there's some cheap stuff that is problematic but any reputable brand ought to be compatible with whatever "rubber-ish" parts are in a marine head, since RV systems sometimes use the same components.

[rwidman]

Originally Posted by hellosailor

Go to an RV store, or any chain selling antifreeze (usually pink) that is designed for RV waste systems. I'm sure there's some cheap stuff that is problematic but any reputable brand ought to be compatible with whatever "rubber-ish" parts are in a marine head, since RV systems sometimes use the same components.

That was my suggestion as well but some folks here took exception to it. It seems they would rather use toxic engine antifreeze and dump it in the ocean when finished with it.

[transmitterdan]

They can't make propylene glycol "compatible" with some materials. it's just chemistry.

Do a little research on toxicity and you will find that EG breaks down rapidly and in small quantities poses no risk to the ocean.

[thinwater]

Originally Posted by rwidman

That was my suggestion as well but some folks here took exception to it. It seems they would rather use toxic engine antifreeze and dump it in the ocean when finished with it.

Present facts please. Honestly, I would be interested.

[thinwater]

Originally Posted by hellosailor

Go to an RV store, or any chain selling antifreeze (usually pink) that is designed for RV waste systems. I'm sure there's some cheap stuff that is problematic but any reputable brand ought to be compatible with whatever "rubber-ish" parts are in a marine head, since RV systems sometimes use the same components.

Ruberish? Oh dear.

Go by some sample materials, soak them in PG, EG, and your favorite brand over the winter, and report back. The neoprene parts will be ruined. I'm sure because I have done this testing. I think you will learn that you are mistaken, but please, do not take my word for it. Test your assumption.

RV heads don't generally have to pump, since the holding tanks is under the floor. Thus, RV heads are very different.

[hlev00]

The mykin.com rubber compatibility sheet shared earlier is interesting. According to Mykin, PG and Ethyl Alcohol (EA) are fine on neoprene, but not good for nitrile - "Doubtful" on their scale. I mention EA because the cheaper RV anti-freeze lists alcohol as a content. The sneaky marketers but label it as a "Propylene Glycol antifreeze". However their own MSDS shows that it is ~20% EA and only 5% PG. I've read where the cheaper EA based antifreezes are harder on head components than PG based, though according to the Mykin reports they are all relatively equivalent on how the affect nitrile and neoprene.

Only EG is reported by Mykin as satisfactory for nitrile components. This seems to be consistent with the Practical Sailor report and recommendations, and tests done by others.

[boatpoker]

Shop vac & drain the system and forget all this nonsense.

[rwidman]

Originally Posted by thinwater

Present facts please. Honestly, I would be interested.

Go to the library and read a book on boat maintenance. Read the chapter on "winterizing".

[rwidman]

Originally Posted by boatpoker

Shop vac & drain the system and forget all this nonsense.

And that will work just fine.

[NahanniV]

Originally Posted by boatpoker

Shop vac & drain the system and forget all this nonsense.

This is what I do as well for my fresh water system and engine.
I apply the vac to the disconnected pump end of the system and then to each tap.
I try to do it as early as possible and leave all taps and drain plugs open so that any residual moisture can dry.

But the OP is talking about the head pump; There I do put some RV antifreeze in the bowl (LAVAC Head) and pump it through into the mostly empty holding tank.

[boatpoker]

Originally Posted by NahanniV

This is what I do as well for my fresh water system and engine.
I apply the vac to the disconnected pump end of the system and then to each tap.
I try to do it as early as possible and leave all taps and drain plugs open so that any residual moisture can dry.

But the OP is talking about the head pump; There I do put some RV antifreeze in the bowl (LAVAC Head) and pump it through into the mostly empty holding tank.

Works well for the head but I certainly would not do it for the engine as the proper engine anti-freeze has anti-corrosion additives.

[rwidman]

Originally Posted by boatpoker

Works well for the head but I certainly would not do it for the engine as the proper engine anti-freeze has anti-corrosion additives.

We have to know if we're talking about a closed cooling system, the raw water side of a closed cooling system or a raw water cooling system.

A closed cooling system will already have "engine coolant" in it. The toxic stuff. The raw water portion can be winterized with non toxic "RV" antifreeze and a raw water cooled engine can be winterized with the same.

[NahanniV]

Originally Posted by boatpoker

Works well for the head but I certainly would not do it for the engine as the proper engine anti-freeze has anti-corrosion additives.

You use your shop vac on your head ?
How ?
Yuck !

As far as the engine: Mine has closed cooling, the closed part only needs a check (or change) of the coolant. The heat exchanger/raw water pump gets drained and vacd. I don't think it needs any corrosion inhibitors to sit dry over the winter.

[boatpoker]

Originally Posted by rwidman

We have to know if we're talking about a closed cooling system, the raw water side of a closed cooling system or a raw water cooling system.

A closed cooling system will already have "engine coolant" in it. The toxic stuff. The raw water portion can be winterized with non toxic "RV" antifreeze and a raw water cooled engine can be winterized with the same.

You are correct. I assumed he was talking about the raw water side because the other side would be just dumb.