Dear fellow car lovers,

I owned a 97 mercury grand marquis with the handling package that was destroyed by a driver that rearended me at 40 mi/hr when I was at a dead stop. My replacement car was a 2001 Lincoln Town Car Cartier L. Due to lack of engine coolant maintenance I was forced to replace my head gaskets on my 4.6L engine. I did a little research on coolant types and found the following. For reference you might want to check the website for Zerex brand coolants and Caterpillar Tractor company's pamphlets on fluid types. Yes you saw right Caterpillar. I will explain in a moment.

I am a scientist with a Ph'D in chemistry and do understand coolants since chemists deal with materials. The best coolant for heat transfer is water for your engines. This statement is verified both in the physical properties of water and by engineers who have tested water as a heat transfer fluid. But water has 2 problems with it that argue against using only water as a heat transfer agent.

1. Water, being a "universal solvent", will disolve many things. Engines have surfaces of copper, iron, aluminum, tin, and other metal alloys that make up the engine. Since salts will develop over time due to disolved carbon dioxide (carbonic acid) in water and heat, when water is in direct contact with these metal surfaces, corrosion will develop and engine damage will result.

2. Water also expands when it freezes and will cause cracking in the block and heads when it freezes.

To deal with the freezing problem very early in coolant history, methanol and ethanol mixtures with water were used. This is a problem since both alcohols will burn quite nicely and will lead to problems with fires. An alternative was found though with the substitution of ethylene glycol mixtures with water as a freezing point depressant in mixtures with water. This has been so successful that this type of coolant mixture predominates in the market today and has been used with variations for over 70 years. However for some who may be environmentally concious, propylene glycol is marketed as a substitute antifreeze but is not recommended by any engine manufacturer in existence today. The reason is heat transfer. Water, with an arbitrary heat transfer value of one, compares with ethylene glycol with a heat transfer capacity about half as much as water with propylene glycol having a heat tranfer capacity of one quarter that of water. Modern engines create tremendous amounts of heat and the coolant is needed to conduct the heat away from parts that may melt, bend, or warp when exposed directly to the heat of burning gasoline.

If you notice I said nothing about corrosion. Corrosion problems have been noted for many decades in engines which lead to the development of additive packages for coolants. One note however needs to be made here about the color of coolants. Any coolant can be dyed whatever color is desired by the purchaser of the coolant. As a result, do not rely solely on the color of the coolant to tell you the type of coolant. Also in discussion with a Zerex representative about coolants it was mentioned there is no "universal coolant" with a corrosion additive package that is compatible with all coolants. So do not get caught in this trap.

This said there are 4 different types of coolants with additive packages that are not cross compatible with each other. However all of the coolants contain ethylene glycol for freeze suppression and some sort of buffered basic salt additives for corrosion inhibition. I will name the coolant types in order of use.

1. The first is called Inorganic Acid Technology (IAT). This type of coolant has been around for many decades and works quite well when maintained. This is used both in cars and in heavy trucks with different levels of anticorrosion inhibitors used depending on application. Since silicate salts are a major substituent in these coolants most of these coolants are opaque due to the undissolved silicates in the coolant. This, plus depletion of the corrosion protection additives over a relatively short period of time, requires this type of coolant to be changed every 2 years. This type of coolant is used in all pre 2001 Ford products with the exception for Dexcool as noted below.

2. The next type is Dexcool. This coolant is an organic acid technology coolant (OAT) and was developed by GM for extended service intervals. Ford did try this out in one of there vehicles for 1999 but found so many problems with this type of coolant they discontinued use of this coolant. The main problem is that this coolant uses 1,4-benzenedicarboxylic acid as one of the buffer constituents in the coolant. Coupled with ethylene glycol in the presence of oxygen and metal oxides, this will form a brown sludge in the coolant. Every mechanic including former GM mechanics recommend flushing and changing to a different coolant type AS SOON AS POSSIBLE. As far as I know, you must not use any coolant that is Dexcool or Dexcool compatible in your vehicle under any circumstances.

3. The third type is the G-05 spec coolant. This coolant uses a Nitrated Organic Acid Technology (NOAT) additive package. This type is used by Ford, Chrysler, Audi, and Mercedes Benz among others. This is a good coolant but needs servicing every 3 years. You will find this in all 2001 and later Ford products.

4. The forth type is Caterpillar's EC-1 specification coolant. To meet this specification you must test 6 engines for 6000 hours of use with at least one engine having a radiator with an aluminum core and one engine having a copper/lead solder core. It is required when these engines are finished testing you test both the coolant and tear apart the engine to note any wear/corrosion in the engine. The specifications are writen so tightly that to pass essentially you should have no corrosion or wear in the engine. When I asked a Caterpillar representative about use of their coolant type and did they see any coolant related issues their answer was no if all their recomendations are followed to the letter. This unique coolant will last for up to 6 years or 600,000 miles if you follow Caterpillar's recomendations. Since they build engines for 24/7 operation with little downtime for maintenace, this is a big thing they have done to improve reliability of their product.

All coolants use water for dilution to get the freeze protection. Common dilutions are a 1:1 ratio glycol/water for -34F freeze protection or 3:2 ratio of glycol/water for -54F freeze protection. All coolant manufacturers and engine manfactures today require the use of distilled water or deionized water in their coolant mixtures. This is due to dissolved salts in the water from standard tap water, well water, or drinking water that create scale inside the engine block and block the coolant passages. This said the recommended procedure for changing coolant (rarely followed) is below. This procedure will flush any old stubborn dirt (think corrosion) out of the block.


1. Flush old coolant out of cooling system with distilled water until water runs clear. This will take about 20 gallons of water in a Ford Crown Victoria/Mecury Grand Marquis/Lincoln Town Car or other 4.6 liter Ford engine.

2. Drain water in coolant resevoir and radiator and add coolant concentrate to restore 1:1 ratio or 3:2 ratio of glycol/water in coolant.

3. Make sure there is no air pockets left in the engine before running down the road.

To change coolant types from the old green coolant to either the late model Ford G-05 coolant or Caterpillar's EC-1 coolant following the recomendation of Caterpillar for changing from the old IAT coolant to the EC-1 coolant is a good way to go.


1. Flush old coolant out of cooling system with distilled water until water runs clear. This will take about 20 gallons of water in a Ford Crown Victoria/Mecury Grand Marquis/Lincoln Town Car or other 4.6 liter Ford engine.

2. Add Caterpillar coolant cleaner and run engine for 30 minutes. (This cleaner is less harsh on the cooling system and will get your engine clean)

3. Flush cleaner mixture out of cooling system with distilled water until water runs clear. This will take about 20 gallons of water in a Ford Crown Victoria/Mecury Grand Marquis/Lincoln Town Car or other 4.6 liter Ford engine.

4. Drain water in coolant resevoir and radiator and add coolant concentrate (Either G-05 or EC-1 coolant) to restore 1:1 ratio or 3:2 ratio of glycol/water in coolant.

5. Make sure there is no air pockets left in the engine before running down the road.

I used this procedure in my 2001 Lincoln Town Car and have found that I pulled a lot of black sludge out of my engine and now I find the engine warms faster and runs better than before. It is in all cases better to maintain coolant properly than to spend $3000 on a head gasket/intake manifold replacement as I had to do.

Good luck
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Stalag;___________Just for Rizzo I am posting this in my sig. Coolants
2001 Lincoln Town Car Cartier L, 1997 Mercury Grand Marquis (extinct)
On my LTC the following mods/upgrades were added. Heinous motorsport control arms, Command Automotive SD-1 rotors (these rotors can no longer be obtained), Calipers by Goldlinebrakes.com in silver with Hawk HPS pads (now running Ford OEM), MSD COP's. MZT is also applied with programming from BOC. j-mod is now done. Final rebuild of transmission done by Gearstar.