Coloring your cooling system service

Jan. 1, 2020
The good news is that most manufacturers are moving toward some type of Globalized Engine Coolant formulation in an attempt to fully utilize their engineering resources, lower development costs and shrink inventory requirements. This truly is good ne

The color game continues as Ford goes orange.

underhood cooling systems Ford engine coolant repair shop training technician training A/C training automotive aftermarket

The good news is that most manufacturers are moving toward some type of Globalized Engine Coolant formulation in an attempt to fully utilize their engineering resources, lower development costs and shrink inventory requirements. This truly is good news for shop owners, because eventually you will have to stock only one coolant for all engines just like you used to years ago.

The latest news is that Ford has announced a new Motorcraft Specialty Orange Engine Coolant will be used in all of its current production and new engines. The switch-over requires Ford to re-engineer some cooling systems on the current engines and to phase-out all of the other engines.

Depending on your past experiences, the news you might not want to hear is that we have seen this Specialty Orange Coolant before.

A Little History

In the early 1980s, Ford started working with antifreeze manufacturers to come up with globalized formulation.

European manufacturers were abandoning phosphate-based technology, because phosphates tend to form scale. At the same time Asian manufacturers were moving away from silicates, which had a problem getting into water pump seals and destroying them.

Ford first started using the newly developed coolants after extensive durability testing across every vehicle platform Ford had in production. More than 40 million fleet test miles were completed during the early 1980s.

As vehicles have became steadily globalized over the years, antifreeze technology naturally has followed. And by the early 1990s, the big three in coolant manufacturers — Chevron/Texaco, Honeywell and Ashland — responded to Ford's (and other manufacturers') requests and created coolants with an additive package that best suited all of their global markets.

The New Orange Coolant

Ford's Motorcraft Specialty Orange Engine Coolant, as you might have guessed, is orange-colored and relies on a traditional ethylene glycol-base with extended life additives. If properly mixed in a 50/50 mixture of coolant and distilled water, it provides year-round antifreeze, anti-boil and corrosion protection down to -34°F and boiling protection up to 265°F.

Besides a healthy quantity of ethylene glycol, Ford's new coolant contains 1 to 5 percent 2-Ethyl hexanoic acid (2-EHA), which is a very close formulation to another famous orange extended life coolant.

Being classified as an Organic Acid Technology (OAT) type, Motorcraft Specialty Orange Engine Coolant does not contain silicates, nitrates or borates. The OAT additives react with wet metals to form thin, strong layers of protection that deplete slower and offer extended service life, but must remain in constant contact with the surfaces in order to protect them.

Ford says you should use the coolant only when specified and that it does not play well with other coolants except DEX-COOL. So is Ford working with General Motors (GM) as far as engine coolant is concerned?

Well, not exactly.

While traditionally associated with GM, DEX-COOL is technically a coolant specification produced by many coolant manufacturers for a multitude of manufacturers and aftermarket suppliers. The Motorcraft product meets GM's DEX-COOL specification (GM 6277M) and is compatible with all other DEX-COOL engine coolants with similar specifications.

Lessons Learned

We have learned from prior experience with DEX-COOL that coolants containing 2-EHA should be used only in engines that have been updated with rubber, plastic and nylon cooling system components that can handle 2-EHA's capacity to make these components soft. This is being addressed by Ford by limiting the use of their Motorcraft Specialty Orange Engine Coolant to only updated or new engine lines.

We also have learned that 2-EHA is an excellent cleaner and will have the inside of any cooling system squeaky clean in no time. While this is not a bad thing in and of itself, it does create a problem if squeaky clean bare metal is exposed to a humid environment. Can you say rust?

This is why so many early DEX-COOL systems produced the brown sludge that choked up radiators and created a general mess for technicians.

In a recent training session at the Mobile Air Conditioning Society (MACS) annual convention, ACDelco trainer Mark Ingram addressed the problem. According to Ingram, the main issue that caused the rust problem was air entering the system, either from a malfunctioning radiator cap, leaking system or lack of maintenance.

This caused metal components to be exposed and loose corrosion protection from the additive package. Once the system was serviced, the cleaning action of the additive package removed the rust from the system and concentrated it (mostly) in the radiator.

Servicing the Cooling System

Ford states its factory fill of Motorcraft Specialty Orange Engine Coolant will last six years or 100,000 miles and should be changed every three years or 50,000 miles thereafter. So you might be asking why the difference in intervals?

Well, Ford uses de-ionized water for the 50/50 mix on the assembly line, and if it could guarantee that everyone who services their cooling systems in the aftermarket would do the same, the intervals would not be different. It obviously isn't taking bets that will happen. Because OAT coolant takes about 5,000 miles to establish protection, and any time the metal is not in contact with coolant the protection ceases, using pure water for the factory-fill mixture helps protect the system until the mixture has done its job.

So how do you know when the coolant has seen its useful life's end? According to ACDelco's Ingram, "despite the 100,000-mile service interval, OAT coolants should be checked often for degradation."

The tool of choice for checking coolant concentration for most technicians is the venerable coolant hydrometer, yet according to the gurus at MACS, it is the least accurate method.

Hydrometers measure the freeze protection of coolant by measuring the specific gravity of the solution of water and glycol and are meant to be used at 68 degrees. So what's the big deal about measurement temperature? Well as temperature changes, so does specific gravity. A 50 degree difference in temperature can change the calculated percentage of coolant concentration by 15 percent. How many technicians take the time to reference manufacturer charts to calculate for temperature shift when taking a reading with a ball/disc style hydrometer?

MACS' recommendation is to always use a refractometer for the best accuracy. They work by reading the concentration of water soluble fluids and are almost as easy to use as a hydrometer. Simply place a few drops of coolant on the prism, hold the unit up to a light source and read the scale.

Calibration, always important when taking measurements, also is easy. Simply clean the prism and place a few drops of tap water on it. Look into the eyepiece and check to make sure the separation line is at zero. If not, turn the adjustment screw until it is.

Because refractometers read on a Brix scale rather than actual percent, you must multiply the refractometer reading by your coolant's refractive index, which is usually located on the product label, to determine coolant concentration percentage.

Now that you have determined the system needs to be serviced and drained the coolant (you did remove all the engine drain plugs first, right?), how are you going to refill and vent the system? You probably already know that modern cooling systems can be tough to fill and in Northern climates, you must eliminate the air pockets so the heater works. But, you can't just lift the front of the vehicle and pour coolant into the fill neck.

First begin by checking your service information system for a manufacturer recommended procedure and air bleed locations. While you're in there, check all the drain plug locations and make sure you did not forget any.

While the best way to drain, fill and vent is to use a specific machine designed to do the job and backflush the system too, much can be said about the less expensive vacuum filler/bleeder unit. Many manufacturer assembly lines use vacuum filling because it is efficient and dramatically lessens the chances of forming an air pocket, especially in cooling systems prone to this malady.

Sure, you can do a complete drain and refill without special tools, but it might take repeated draining, filling, thermocycling and topping off to achieve a merely mediocre result. Aren't there are more profitable ways to spend your time?

As we approach 15 years since the first introduction of OAT technology and better understand the environment in which it works best, we are better prepared to utilize its unique properties to serve our customers.

Jim Marotta is a freelance writer with more than 17 years' experience in the automotive industry. He currently works as a technical writer for

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