Propylene Glycol anti-freeze engine coolant
recurve
10-08-2004, 04:03 PM
Hi, it's me. The bookworm wannabe mechanic. Looking for ways to extend the life of our trucks. Getting ready to do a coolant flush on our '95 and '97 Blazers. I am trying to decide what type of anti-freeze to refill with and have discovered three types:
1) traditional ethylene glycol (often a green color)
2) DEX-COOL "death cool" - a super ethylene glycol (often an orange color)
3) propylene glycol
I'm thinking about switching to propylene glycol from a company called "Sta clean" but I wanted to recap what I've read and get everyone's 2 cents about the merits of this.
Engine coolant's purpose - general info
==============================
Our trucks cool the engine by passing water past hot metal parts on the engine. The water absorbs the heat and then cools down again once it comes to the radiator. Water, by itself, does a fairly decent job of this without mixing it with "anti-freeze." I've read that in moderate climates, it's ok to use pure water without anything else if your engine is not driven hard.
So what does anti-freeze do? It lowers the freezing point and raises the boiling point of water. Instead of freezing at 32 degrees, antifreeze changes the freezing point to negative 32 degrees. Instead of boiling at 212 degrees, antifreeze changes the boiling point to something higher like 250 degrees. In cold climates, you won't have a brick of ice in your engine. In harsh driving conditions, the water won't evaporate as easily when temperatures rise and thus provide better cooling.
Ever wonder why salt causes snow to melt faster? It works the same way anti-freeze does. Any "salt" that can dissolve in water will lower the freezing point and raise the boiling point. Adding salt might drop the freezing point to 10 degrees instead of 32, if the outside temperature is 15 degrees then things melt. Adding salt to water also raises the boiling point, many people who cook in the mountains regularly add salt to their water to get the proper cooking temperature.
The green stuff - traditional ethylene glycol
==============================
The green stuff does an adequate job as long as it is changed every one or two years - flushed out and replaced (so I've read). This should not be neglected, even if your car seems fine. ethylene glycol is basically a type of "salt" that dissolves in water. Just like salt on the road will rust out the underside of your truck, the "salt" in antifreeze *could* do the same inside your truck. There are inhibitors that stop the antifreeze from becoming very acidic and eating away at things. After a year or two, those inhibitors are depleted and the coolant has become a crude battery. Things will start to rust.
Ethylene glycol is very toxic, and tastes great! Seriously, it is sweet and yummy. Just a little bit could kill a cat or bird or small child. It will eat away your paint if you spill it on your truck. Eat will destroy your bearings if you get a crack in your head gasket.
DEX-COOL aka "Death Cool"
==============================
DEX-COOL is also ethylene glycol based but has a different inhibitor package. It is good for five years or 100,000 miles (whichever comes first). That means you don't have to flush it as often (five times less often as the green stuff). But if it gets contaminated, perhaps by a bad radiator cap that lets too much air into the system, you'll get a lot of rust buildup before the rated "5 year" period. That's how it got the name "death cool."
The following link gives some good information about how to keep a DEX-COOL system in good shape. Note: the video it refers to is no longer available. It is now "restricted access" and you have to be someone named "David O" to get a copy. Luckily, the review of the video at this link is very thorough:
http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.htm
The other thing about DEX-COOL is that it is "silicate free" which means that it is less abrasive than the green stuff. This is good for aluminum parts which might scratch easily, at least that is the theory.
In a nut shell, think of DEX-COOL as being like the traditional stuff but it might last longer between flushes. Keep a good radiator cap on it and keep coolant levels up to the HOT level when it is cold - the key idea is to minimize the chance of air getting into the system.
Propylene Glycol
==============================
Propylene glycol is less toxic and has a bitter taste. In fact, propylene glycol can be found in some cosmetics. It won't eat away your paint like the traditional stuff and if you get a crack in your head gasket, it won't eat away your bearings. Propylene glycol is biodegradable.
On the downside, propylene glycol is more expensive than the traditional stuff. Also, it doesn't lower the freezing point as much as the traditional stuff. If it gets extremely cold in your neck of the woods, propylene glycol may not be an option.
I've found one company that does nothing but manufacture and market propylene glycol anti-freeze. They are Sta-Clean and their web site is:
http://www.stacleanantifreeze.com/
sta-clean is not sillicate free, but has a minimal amount. I wonder how much aluminum is in our Blazers and if this could be a problem? I'm seriously thinking about using this anti-freeze.
They claim that they have extended drain intervals similar to DEX-COOL because they have a good inhibitor package. They also sell the inhibitor package separately to add to the coolant.
NEO, AMSOIL, Prestone LowTox, and some other companies sell propylene glycol anti-freeze but from what I've read, it looks like sta-clean might be the best. Unfortunately, I can't find any impartial studies that clearly recommend one type of propylene glycol anti-freeze over another.
I'd like to hear everyone's thoughts.
Thanks,
-- recurve
1) traditional ethylene glycol (often a green color)
2) DEX-COOL "death cool" - a super ethylene glycol (often an orange color)
3) propylene glycol
I'm thinking about switching to propylene glycol from a company called "Sta clean" but I wanted to recap what I've read and get everyone's 2 cents about the merits of this.
Engine coolant's purpose - general info
==============================
Our trucks cool the engine by passing water past hot metal parts on the engine. The water absorbs the heat and then cools down again once it comes to the radiator. Water, by itself, does a fairly decent job of this without mixing it with "anti-freeze." I've read that in moderate climates, it's ok to use pure water without anything else if your engine is not driven hard.
So what does anti-freeze do? It lowers the freezing point and raises the boiling point of water. Instead of freezing at 32 degrees, antifreeze changes the freezing point to negative 32 degrees. Instead of boiling at 212 degrees, antifreeze changes the boiling point to something higher like 250 degrees. In cold climates, you won't have a brick of ice in your engine. In harsh driving conditions, the water won't evaporate as easily when temperatures rise and thus provide better cooling.
Ever wonder why salt causes snow to melt faster? It works the same way anti-freeze does. Any "salt" that can dissolve in water will lower the freezing point and raise the boiling point. Adding salt might drop the freezing point to 10 degrees instead of 32, if the outside temperature is 15 degrees then things melt. Adding salt to water also raises the boiling point, many people who cook in the mountains regularly add salt to their water to get the proper cooking temperature.
The green stuff - traditional ethylene glycol
==============================
The green stuff does an adequate job as long as it is changed every one or two years - flushed out and replaced (so I've read). This should not be neglected, even if your car seems fine. ethylene glycol is basically a type of "salt" that dissolves in water. Just like salt on the road will rust out the underside of your truck, the "salt" in antifreeze *could* do the same inside your truck. There are inhibitors that stop the antifreeze from becoming very acidic and eating away at things. After a year or two, those inhibitors are depleted and the coolant has become a crude battery. Things will start to rust.
Ethylene glycol is very toxic, and tastes great! Seriously, it is sweet and yummy. Just a little bit could kill a cat or bird or small child. It will eat away your paint if you spill it on your truck. Eat will destroy your bearings if you get a crack in your head gasket.
DEX-COOL aka "Death Cool"
==============================
DEX-COOL is also ethylene glycol based but has a different inhibitor package. It is good for five years or 100,000 miles (whichever comes first). That means you don't have to flush it as often (five times less often as the green stuff). But if it gets contaminated, perhaps by a bad radiator cap that lets too much air into the system, you'll get a lot of rust buildup before the rated "5 year" period. That's how it got the name "death cool."
The following link gives some good information about how to keep a DEX-COOL system in good shape. Note: the video it refers to is no longer available. It is now "restricted access" and you have to be someone named "David O" to get a copy. Luckily, the review of the video at this link is very thorough:
http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.htm
The other thing about DEX-COOL is that it is "silicate free" which means that it is less abrasive than the green stuff. This is good for aluminum parts which might scratch easily, at least that is the theory.
In a nut shell, think of DEX-COOL as being like the traditional stuff but it might last longer between flushes. Keep a good radiator cap on it and keep coolant levels up to the HOT level when it is cold - the key idea is to minimize the chance of air getting into the system.
Propylene Glycol
==============================
Propylene glycol is less toxic and has a bitter taste. In fact, propylene glycol can be found in some cosmetics. It won't eat away your paint like the traditional stuff and if you get a crack in your head gasket, it won't eat away your bearings. Propylene glycol is biodegradable.
On the downside, propylene glycol is more expensive than the traditional stuff. Also, it doesn't lower the freezing point as much as the traditional stuff. If it gets extremely cold in your neck of the woods, propylene glycol may not be an option.
I've found one company that does nothing but manufacture and market propylene glycol anti-freeze. They are Sta-Clean and their web site is:
http://www.stacleanantifreeze.com/
sta-clean is not sillicate free, but has a minimal amount. I wonder how much aluminum is in our Blazers and if this could be a problem? I'm seriously thinking about using this anti-freeze.
They claim that they have extended drain intervals similar to DEX-COOL because they have a good inhibitor package. They also sell the inhibitor package separately to add to the coolant.
NEO, AMSOIL, Prestone LowTox, and some other companies sell propylene glycol anti-freeze but from what I've read, it looks like sta-clean might be the best. Unfortunately, I can't find any impartial studies that clearly recommend one type of propylene glycol anti-freeze over another.
I'd like to hear everyone's thoughts.
Thanks,
-- recurve
86TATpi
10-08-2004, 04:32 PM
Anti-freeze has additives in it. They lubricate the water pump, prevent rust and corrosion, raise boiling temp and lower freezing temp. Anti-freeze by itself will freeze. You seem to have the differences down pretty well. Ethylene works best, propylene is safer, dex-cool has a longer life. If the car has the dex-cool in it I keep it. The biggest problem I see with it is the claim of it lasting as long as it's supposed to and people don't check it.
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