First there were 100,000-mile platinum-tipped spark plugs.
Now there is a new engine coolant formulated to last five years/100,000 miles – that’s three years/70,000 miles longer than conventional coolants.
Dex-Cool, which is made by Texaco, is being used exclusively by General Motors in some buildout 1995 models and all 1996 cars and trucks except Saturn and Geo.
GM postponed using Dex-Cool in Saturn cars until the 1997 model year because it did not have enough data to make use of the new coolant possible in 1996 models. Geo vehicles, built in conjunction with Suzuki and Toyota, use a different coolant.
Dex-Cool is ethylene glycol-based like other coolants, said Wayne Bradley, senior project engineer at GM’s Service Technology Group. What sets this new antifreeze apart from the rest, aside from its bright orange color, is its inhibitor formula, which forms a film on aluminum surfaces and protects engine surfaces from corrosion.
“It’s the inhibitor package that depletes with age and limits the life of antifreeze,” Bradley said. “Dex-Cool is made possible by a change to organic acid-based inhibitors.”
Bradley said GM went to the extended-life antifreeze because studies show that customers want longer service intervals. Studies also found that many consumers change their antifreeze every five or six years rather than at the manufacturer-recommended two-year/30,000-mile interval. In addition to its longer life, Bradley listed other Dex-Cool benefits:
It enhances the performance of the water pump seal and protection of the heat exchanger.
Longer service intervals reduce the need for new coolant and decrease the impact of used coolant on the environment. Used coolants contain lead and other contaminants absorbed from the engine that are harmful to ground water.
Dex-Cool should not be mixed with conventional coolants. This is especially important in vehicles with less than 3,000 miles, Bradley said. If conventional antifreeze is mixed with Dex-Cool in new vehicles during dealer prep, the engine should be drained and refilled with Dex-Cool.
However, if the two coolants are mixed after the vehicle has been driven 3,000 miles, no immediate problems will occur, but the service interval is reduced from five years/100,000 miles to two years/30,000 miles.
Bradley said GM has taken several measures to alert service technicians and consumers that a vehicle has been filled with Dex-Cool:
Orange coloring (conventional coolants are green).
Under-hood labels that caution “Use Dex-Cool Coolant Only.”
Owner’s manuals of 1996 GM vehicles specify that the engine has been filled with Dex-Cool, and a supplement GM has added to its 1995 owner’s manual to alert consumers and service technicians.
Bradley said it is “imperative” that independent aftermarket service shops learn about Dex-Cool, so that they won’t inadvertently top off a Dex-Cool-filled engine with standard coolant.
Dex-Cool may be used in older GM and non-GM vehicles, except those with high-lead solder radiators.
Older vehicles can be filled with Dex-Cool, but vehicles with more than 3,000 miles will not benefit from its anti-corrosive feature, and the recommended service interval remains at two years/30,000 miles. Older vehicles would benefit from Dex-Cool’s enhanced water pump seal properties, Bradley said.
