factory antifreeze
- Thread starter mbradley
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greasefingers
New member
Not sure but this something I found on the web. I lost the link, but copied it into Word.
Under The Cap, Larry Carley, Tire Review, November 2000
Today's Coolant Options Require Close Attention, Different Techniques
When you open a radiator cap these days, you're never quite sure what you're going to find. Antifreeze chemistry has undergone some significant changes in recent years, and the familiar green antifreeze long used in most vehicles is being replaced with a spectrum of not-so-familiar antifreezes that range in color from red to orange to pink to blue.
So it's important to know what type of antifreeze is in the system so you can add a compatible coolant, or replace it with one that provides equivalent or better protection.
Ethylene Glycol
Ethylene glycol (EG) has been the main ingredient in almost all automotive antifreezes for many years, and will continue to be for the foreseeable future. Straight ethylene glycol freezes at about 8 F, boils at 330 F, and carries heat about 15% less efficiently than water. But when mixed in equal parts with water, it creates a coolant well-suited to year-round driving for most applications.
The recommended 50/50 mixture of EG and water provides freezing protection down to -34 F and boilover protection to 265 F in a radiator with a 15 psi cap. If the proportion of antifreeze to water is increased to 70% EG and 30% water, the freezing point drops to -84 F and the boiling temperature goes up to 276 F. Mixtures greater than 70/30 are not recommended because the coolant's ability to carry heat declines as the proportion of antifreeze increases.
Straight EG antifreeze should never be used in an engine because it may allow the engine to overheat. Likewise, straight water should never be used because it provides no freezing, boiling or corrosion protection.
Propylene Glycol
Another base ingredient that is used in place of EG in some aftermarket antifreezes (like Prestone's LowTox and Safe Brands' Sierra antifreeze) today is propylene glycol (PG). The coolant's thermal characteristics are similar to those for EG: a 50/50 mixture of PG and water provides freezing protection down to -26 F and boilover protection to 256 F. If the coolant mixture is increased to 60/40, coolant freezing protection goes down to -54 F.
The main advantage of PG compared to EG, however, is that it is considered nontoxic to animals. That doesn't mean it is safe to drink, but it greatly reduces the risk of poisoning a pet.
Pure PG boils at 370 F and provides freezing protection down to -70 F, so it is sometimes used straight without any water at all as a coolant in racing applications. Running PG straight provides better cooling because there is no water to vaporize in hot areas of the cylinder. This also allows the use of very low pressure or even no pressure cooling systems.
While PG and EG are both compatible and can be intermixed without affecting cooling performance, intermixing the two different antifreezes is not recommended because doing so defeats the reduced toxicity advantages of PG. Also, if a vehicle's cooling system is filled with an extended life EG coolant, adding PG - not currently formulated for extended service - will reduce the service life of the coolant mixture to that of a conventional green coolant.
Intermixing PG and EG antifreeze also makes it impossible to get an accurate indication of the coolant's strength if you're using a hydrometer to check coolant concentration. The specific gravity of EG and PG are different, so a mixture of the two will usually indicate a lower freezing point than the coolant actually provides.
The best way to determine the concentration of PG in uncontaminated coolant (no EG present) is to use a refractometer. The reason is because the specific gravity of PG increases up to about a 70% concentration, then falls off considerably. Consequently, a 100% PG solution will read the same as a 45% solution on a hydrometer.
General Motors and others approve PG as an acceptable replacement coolant, but if making a change it's important to remove all of the old EG coolant before adding PG to the system.
Under The Cap, Larry Carley, Tire Review, November 2000
Today's Coolant Options Require Close Attention, Different Techniques
When you open a radiator cap these days, you're never quite sure what you're going to find. Antifreeze chemistry has undergone some significant changes in recent years, and the familiar green antifreeze long used in most vehicles is being replaced with a spectrum of not-so-familiar antifreezes that range in color from red to orange to pink to blue.
So it's important to know what type of antifreeze is in the system so you can add a compatible coolant, or replace it with one that provides equivalent or better protection.
Ethylene Glycol
Ethylene glycol (EG) has been the main ingredient in almost all automotive antifreezes for many years, and will continue to be for the foreseeable future. Straight ethylene glycol freezes at about 8 F, boils at 330 F, and carries heat about 15% less efficiently than water. But when mixed in equal parts with water, it creates a coolant well-suited to year-round driving for most applications.
The recommended 50/50 mixture of EG and water provides freezing protection down to -34 F and boilover protection to 265 F in a radiator with a 15 psi cap. If the proportion of antifreeze to water is increased to 70% EG and 30% water, the freezing point drops to -84 F and the boiling temperature goes up to 276 F. Mixtures greater than 70/30 are not recommended because the coolant's ability to carry heat declines as the proportion of antifreeze increases.
Straight EG antifreeze should never be used in an engine because it may allow the engine to overheat. Likewise, straight water should never be used because it provides no freezing, boiling or corrosion protection.
Propylene Glycol
Another base ingredient that is used in place of EG in some aftermarket antifreezes (like Prestone's LowTox and Safe Brands' Sierra antifreeze) today is propylene glycol (PG). The coolant's thermal characteristics are similar to those for EG: a 50/50 mixture of PG and water provides freezing protection down to -26 F and boilover protection to 256 F. If the coolant mixture is increased to 60/40, coolant freezing protection goes down to -54 F.
The main advantage of PG compared to EG, however, is that it is considered nontoxic to animals. That doesn't mean it is safe to drink, but it greatly reduces the risk of poisoning a pet.
Pure PG boils at 370 F and provides freezing protection down to -70 F, so it is sometimes used straight without any water at all as a coolant in racing applications. Running PG straight provides better cooling because there is no water to vaporize in hot areas of the cylinder. This also allows the use of very low pressure or even no pressure cooling systems.
While PG and EG are both compatible and can be intermixed without affecting cooling performance, intermixing the two different antifreezes is not recommended because doing so defeats the reduced toxicity advantages of PG. Also, if a vehicle's cooling system is filled with an extended life EG coolant, adding PG - not currently formulated for extended service - will reduce the service life of the coolant mixture to that of a conventional green coolant.
Intermixing PG and EG antifreeze also makes it impossible to get an accurate indication of the coolant's strength if you're using a hydrometer to check coolant concentration. The specific gravity of EG and PG are different, so a mixture of the two will usually indicate a lower freezing point than the coolant actually provides.
The best way to determine the concentration of PG in uncontaminated coolant (no EG present) is to use a refractometer. The reason is because the specific gravity of PG increases up to about a 70% concentration, then falls off considerably. Consequently, a 100% PG solution will read the same as a 45% solution on a hydrometer.
General Motors and others approve PG as an acceptable replacement coolant, but if making a change it's important to remove all of the old EG coolant before adding PG to the system.
NoDak
Senior Member
ugh refractometers. had to do this when i was in the USAF working as a HVAC person on heat systems back in the 90's.
we had one that was a pita to use. you had to dab some PG on and look up to the light (sunlight as anything else tended to give false readings) to tell the freeze point. messy and you had to clean the plate and plastic cover gently to prevents scratches.
the base i worked at ran a hi-temp system (brine water at 350-400F and up to 300-400 psi in sched-80 pipe) which transfers heat from the high system to a medium system running PG/H20 (180F at 25-40psi)
hated doing the 55gal drum fill ups of PG into the medium systems cause you had to check the freeze points over several days to make sure you got it down to a decent point.
stuff is just nasty to deal with and if i remember, it stains and shreads clothing pretty easy since i had to get new bdu's after topping of systems before winter.
we had one that was a pita to use. you had to dab some PG on and look up to the light (sunlight as anything else tended to give false readings) to tell the freeze point. messy and you had to clean the plate and plastic cover gently to prevents scratches.
the base i worked at ran a hi-temp system (brine water at 350-400F and up to 300-400 psi in sched-80 pipe) which transfers heat from the high system to a medium system running PG/H20 (180F at 25-40psi)
hated doing the 55gal drum fill ups of PG into the medium systems cause you had to check the freeze points over several days to make sure you got it down to a decent point.
stuff is just nasty to deal with and if i remember, it stains and shreads clothing pretty easy since i had to get new bdu's after topping of systems before winter.
