OK To Winterize Engine With Propylene Glycol?

Witzend · Nov 9, 2012

"the system in my motor" hmmm, wonder what that means. Propylene glycol will work just fine for fresh water cooling systems with heat exchangers. There seems to be some concern with the ethyl alcohol content in some of the cheaper brands attacking rubber components within domestic water systems, but that should not be a problem unless the veins of your fresh water pump are made of cheep rubber. The exhaust components should be all neoprene which ethyl alcohol will not degrade. An added benefit is that when you start up in the spring you will not be polluting the environment with the toxic Ethylene Glycol as it gets pumped into the water.

jrowan · Nov 9, 2012

Propolyne glycol is the way to go on marine diesels, as it is way less toxic then ethelyne glycol. You must use the pink propolyne antifeeeze if the engine is raw water cooled, as ethylene glycol is a LETHAL toxin to marine life (& anything else living). Even if you have a heat exchanger it is still recommended, because if or when U have a leak of coolant that works it way to the bilge it can & will be pumped out by your bilge pump to the open sea. As sailors we have an obligation to keep the ocean & waters we sail in as clean & free of toxins as possible. But thanks for asking before using car antifreeze in your boat's engine.

Rich Stidger · Nov 9, 2012

You might want to consider the benefit of automotive antifreeze that has corrosion inhibitors to protect the interior surfaces of your engine. You can buy the polypropylene formula instead of the ethylene glycol blend that is intended for an engine and has the inhibitors.

Having said that, WM does have a version of "engine recommended" antifreeze that I think has corrosion inhibitors. You would have to check me on this. But I also think that the price is substantially more than half of the price of full strength polypropylene antifreeze.

BTW, the "pink stuff" is often NOT a pure polypropylene formula. Read the label.

Maine Sail · Nov 9, 2012

On a Beneteau 36 I am guessing this engine has a heat exchanger and you are trying to winterize that?

The fresh water side of the system uses an ethylene glycol/EG (automotive or diesel grade engine antifreeze) and in that side you should not use a PG product.

For the raw water side PG is fine so long is it is a true PG and not a PG/alcohol blend. Some strainers, refrigeration heat exchangers etc. have PVC in them and are not very compatible with ethyl alcohol. Also read the label to see if it has a corrosion inhibitor package. The West Marine Pure Oceans PG is a pure PG product that also has corrosion inhibitors.. It is available in -50, -60 & -100F versions and NONE OF IT SHOULD EVER BE DILUTED. These face value ratings are quite misleading... Dilution drastically raises the burst and freeze points. A -50 PG will burst plastics at -10F and thin copper heat exchangers are not much stronger than plastic pipe.. See, misleading...

Generally any RV type antifreeze costing less than 4.99 gal is likely not a pure propylene glycol and is a PG/alcohol. Read the labels.....

Unless you replaced your engine AF with PG ignore the "boys at the club"..

Ralph Johnstone · Nov 9, 2012

What Am I Missing Here .....................

...................... the boys at the club say it's OK to put sea water through the raw water passages of your engine and yet tell you that propylene glycol will corrode it.

By any chance are they power boaters

?

thinwater · Nov 9, 2012

jrowan said:
Propolyne glycol is the way to go on marine diesels, as it is way less toxic then ethelyne glycol. You must use the pink propolyne antifeeeze if the engine is raw water cooled, as ethylene glycol is a LETHAL toxin to marine life (& anything else living). Even if you have a heat exchanger it is still recommended, because if or when U have a leak of coolant that works it way to the bilge it can & will be pumped out by your bilge pump to the open sea. As sailors we have an obligation to keep the ocean & waters we sail in as clean & free of toxins as possible. But thanks for asking before using car antifreeze in your boat's engine.

Simply not true, unless you have different data to present. Yes, propylene glycol (PG) is less toxic to mamals than ethylene glycol (EG) and thus PG MUST be used in all potable systems. However, the toxicity of EG and PG to marine organisms is low and equivalent.
http://www.riskworld.com/Abstract/1996/sraeurop/ab6ad040.htm

As comfirmation, please read the MSDS statements regarding marine toxicity of each product--chose the brand of your choise and look them up. Additionally, about 1/3 less EG is required than PG, making the EG less toxic and contributing less COD.

PG
Ecotoxicity: Water flea Daphnia: EC50 > 10000 mg/L; 48 Hr; UnspecifiedBacteria: Phytobacterium phosphoreum: EC50 = 710 mg/L; 30 min; Microtox testFish: Goldfish: LC50 > 5000 mg/L; 24 Hr; UnspecifiedFish: Guppy: LC50 > 1000 mg/L; 48 Hr; Unspecified If released to water, 1,2-propanediol is expected to degrade relatively rapidly via biodegradation. If released to soil, relatively rapid biodegradation should also occur. Significant leaching in soil can be predicted.

EG
Ecotoxicity: Goldfish LD50= >5000mg/L/24Hr Guppies LC50= 493,000ppm/7D Shrimp (salt water) LC50= >100ppm/48Hr

Certain gasket and hose materials--neoprene--do not care for PG but do well with EG.
http://www.coleparmer.com/Chemical-Resistance

For example, zinc is lethal to fish but people take zinc pills. Dog should avoid chocholate. Toxicity is not so simple.

I'm just trying to be acurate in my postings by looking up the information first.

___________

No, as others have posted, it's not worth doing over.

Gunni · Nov 9, 2012

What is a little alcohol to a raw water heat exchanger? Do I really need to use that pricy pure propylene glycol?

Thinwater: Not to quibble, but I think the concern with glycols in waterways is BOD, not COD.

Don S/V ILLusion · Nov 9, 2012

Actually it is BOD but the difference is academic. You can use the cheap alcohol containing glycol and risk damage to the hoses and rubber components or spend a few extra dollars to ensure no damage. Your choice!

Sail123 · Nov 9, 2012

EG can explode. PG has no such warning label. Something to ponder.

Scott B · Nov 10, 2012

Did you not believe us the first time we tried to help?

http://forums.hunter.sailboatowners.com/showthread.php?t=146917

Maine Sail · Nov 10, 2012

Ducati said:
OK, this is what I used to winterize.

West Marine Pure Oceans -50° (-46°C) Marine Antifreeze provides the ultimate in cold weather and corrosion protection for drinking water systems and all engines. Its premium additive package prevents corrosion of aluminum, copper, brass and solder, but will not harm rubber, seals or hose materials. The 3X-died bright pink color provides excellent blow-through visibility. Formulated with non-toxic, virgin Propylene Glycol (30% Blend), it is tasteless and contains no alcohol. This product is ready-to-use; do not dilute it.
Provides burst protection to -50°F (-46°C) and freeze protection within a range of +12°F to +16°F (-11°C to -9°C)

Good enough or should I use something else?

It is fine unless:

A) It got diluted and you did not suck enough in to keep the freeze protection the same. I have numerous boats I work on, including my own, that take 5+ gallons. What is coming out the exhaust needs to have the same freeze point as what went in.. Merely "seeing pink" as many folks incorrectly do has zero meaning in actual freeze protection. It may be pink but the level/concentration of "pink" may not be anywhere near as strong as it went in.. On customers boats the first time I winterize I test with a sight refractometer at 3 Gal. If the protection is not identical to what it went in as I add another gal. I then test again etc. etc.. The next season I know exactly how much their vessel takes..

B) You live in an area of the country that regularly sees -10F or colder... In that case I would suck in 1 more gal or two of the -100...

zeehag · Nov 10, 2012

propylene glycol i also sold in other stores than west marine--omg!!! is lot less pricey in auto zone. yes they carry it. so does walmart. might wanna shop around. just because you have a boat doesnt mean you need to have to pay extortionally high prices. dont have to pay cost plus 400 percent for alleged marine propylene glycol when regular propylene glycol is exactly same recipe..LOL

thinwater · Nov 10, 2012

Gunni said:
What is a little alcohol to a raw water heat exchanger? Do I really need to use that pricy pure propylene glycol?

Thinwater: Not to quibble, but I think the concern with glycols in waterways is BOD, not COD.

No, not quibling.

However, PG and EG exibit virtually identical COD and BOD per pound. I should have said BOD for clarity, but the statement remains just as true.

thinwater · Nov 10, 2012

Sail123 said:
EG can explode. PG has no such warning label. Something to ponder.

Ethanol (drinking alchohol) can explode. EG and PG are both non-combustible when mixed with water and have flash points above boiling. Both EG and PG are double alchohols (glycols) and will burn if free of water, with ignition requirments about like lubricating oils, though somewhat less heat is released in combustion.

Check facts, please.

Witzend · Nov 10, 2012

thinwater said:
Simply not true, unless you have different data to present. Yes, propylene glycol (PG) is less toxic to mamals than ethylene glycol (EG) and thus PG MUST be used in all potable systems. However, the toxicity of EG and PG to marine organisms is low and equivalent.
http://www.riskworld.com/Abstract/1996/sraeurop/ab6ad040.htm

As comfirmation, please read the MSDS statements regarding marine toxicity of each product--chose the brand of your choise and look them up. Additionally, about 1/3 less EG is required than PG, making the EG less toxic and contributing less COD.

PG
Ecotoxicity: Water flea Daphnia: EC50 > 10000 mg/L; 48 Hr; UnspecifiedBacteria: Phytobacterium phosphoreum: EC50 = 710 mg/L; 30 min; Microtox testFish: Goldfish: LC50 > 5000 mg/L; 24 Hr; UnspecifiedFish: Guppy: LC50 > 1000 mg/L; 48 Hr; Unspecified If released to water, 1,2-propanediol is expected to degrade relatively rapidly via biodegradation. If released to soil, relatively rapid biodegradation should also occur. Significant leaching in soil can be predicted.

EG
Ecotoxicity: Goldfish LD50= >5000mg/L/24Hr Guppies LC50= 493,000ppm/7D Shrimp (salt water) LC50= >100ppm/48Hr

Certain gasket and hose materials--neoprene--do not care for PG but do well with EG.
http://www.coleparmer.com/Chemical-Resistance

For example, zinc is lethal to fish but people take zinc pills. Dog should avoid chocholate. Toxicity is not so simple.

I'm just trying to be acurate in my postings by looking up the information first.

___________

No, as others have posted, it's not worth doing over.

According your referenced web site, as I indicated Neoprene rubber is not affected by Ethel Alcohol. Debunking this issue.
http://www.coleparmer.com/Chemical-Resistance

If PG is moderatly reactive with Neoprene as indicated by this web site, than there should be equally as much a concern with using it in domestic water systems as in fresh water coolant systems and there does not seem to be.

Also The toxicity study you reference. Indicates:
" Based upon the limited available data, no general distinction can be made between aquatic toxicities of ethylene and propylene glycol formulations. There is considerable variability in the observed toxicities of different commercial formulations, especially those of Type II. The chemical factors which account for this variability are unknown".

So I'm not sure this has been looked into carefully enough to indicate that there is not an issue. We do know the EG will metabolize and this is what cause the toxicity and PG is not, so why would you want to dump this is the water in the light of this known information?

zeehag · Nov 10, 2012

why do you dump it into the water--isnt there a way to catch the fluid when you wish to rid boat of it without having it run out the bilge and into water??

Maine Sail · Nov 10, 2012

zeehag said:
propylene glycol i also sold in other stores than west marine--omg!!! is lot less pricey in auto zone. yes they carry it. so does walmart. might wanna shop around. just because you have a boat doesnt mean you need to have to pay extortionally high prices. dont have to pay cost plus 400 percent for alleged marine propylene glycol when regular propylene glycol is exactly same recipe..LOL

Zee,

I paid about $3.50 / gal for six cases of WM Pure Oceans when it was on sale. This is a true PG product with a corrosion inhibitor package. It is not a cheap Propylene Glycol/Ethyl Alcohol blend like you get at many stores selling if for $2.99 - $3.99...

I can't buy Pahnol or any other PG product that has the same specs for much less. The WM price was less than my commercial Hamilton Marine price and less than ANY local option that had a PG product with corrosion inhibitors.

Being that I go through cases of this stuff I SHOP AROUND. Wal*Mart charges $4.99 per gallon for the Prestone PG product and $2.99 for the SuperTech PG/Ethyl Alcohol blend. That is $1.50 more per gallon than I paid at WM. Wal*Mart does not have sales on PG....

You need to compare like for like products most of the $2.99 - $3.99 RV antifreeze products are now a propylene glycol / ethyl alcohol blend. I checked locally with about 15 sources and WM had the best price... Who knows maybe next year they won't and I'll get a good deal on Pahnol or Dow...

zeehag · Nov 10, 2012

maine--in mexico--we do not have west marine---an zaragosa, in puerto vallarta, is beyond belief--have seen no kind of anti freeze there--we need to use the auto and wally places, and under 5 dollars us isnt bad-- the green stuff is all over here, but it is difficult to find that good pg here in my areas of mexico--at least we only need the anti corrosion and anti boilover protection here....nothing will freeze where i am sailing at present....i will post the location when and if i can find good ones here--i still have usa-bought or mazatan-bought antifreeze.