(my theory) When ever you put a silicon based coolant in your cooling system you must and I mean MUST change your coolant every 2 years. The aluminum pipes on heater cores seem to often fail because of this. As the coolant ages the silicon tends to bond to each other forming larger particals and it begins to eat away at aluminum like a sand blaster. The silicon contained in green coolant isnt the healthiest stuff you can put in a modern cooling system. I've also seen hardened clusters of silicon bonded to aluminum surfaces. I've seen some pretty bad pitting on machined mating surfaces of aluminum. It's also a bad idea to mix the two, although the result doesn't immediately turn into witches' brew.From what 'I've experienced' and have seen the conventional green coolant attacts aluminum towards the end of its life cycle vigorously. 'Cars born with green coolant shouldn't be changed to orange,' Turcotte advises. But it eats old-style radiators with lead solder, and the inhibitors work too slowly to protect against the sort of corrosion that happens so fast it actually erodes metal-for example, the cavitation likely in the imperfectly designed water pumps of older cars. The GM Dex-Cool formula works fine in systems designed for it.

The promise of OAT is long-life corrosion protection, on the order of six years/ 100,000 miles for the initial fill instead of the two years/50,000 miles that was typical with the old green stuff. Interestingly, Turcotte says that as the materials improve for the white plastic overflow bottles of new cars, and they become less yellowing over time, automakers are becoming more venturesome in choosing coolant colors. It comes in too many colors to pretend this type is color-coded. Instead of OAT, most new cars now use a 'hybrid' antifreeze that's formulated with both OAT and the silicate inhibitors from green (Japanese hybrids have different inhibitors). VW, Audi, and Porsche are OAT users, too, but most others have resisted. Ford changed a few models to OAT, then backed away from it. General Motors pioneered this chemistry starting with 1996 models in the U.S. One of the new types is 'organic acid technology,' or OAT. Most of what you see on the shelves at Wal-Mart and AutoZone is conventional, including the yellow bottles of Prestone and the white bottles of Zerex. It turns out that an antifreeze transplant into older cars will work fine with one of the new types the other will probably kill the patient. The 'old' antifreeze technology started in the '60s, improved in the '70s, Turcotte says, and was superseded in cars of the '90s by two new technologies. Of course, no doctor writes the prescription before he considers the patient. I was hoping that technology, as it marches relentlessly toward obsoleting everything I own, might also have created new antifreeze formulas that would bring forbearance and frustration to the chemicals frolicking under my aging radiator caps. The next stage: As detritus migrates through the system, it settles in the most confined spaces.

A sticking thermostat can be an early indicator. Perhaps the battle is already going badly in your car. The freeze protection is permanent, but the additives are consumed in battle, so to speak.Ībout half the additive is made of buffers to control acid buildup the other half is corrosion inhibitors to protect metals. In normal circumstances, you also gain corrosion resistance. When you dilute that blend 50-50 with water, as the makers intend, you push down the freeze point to minus 34 degrees Fahrenheit. Modern antifreeze, he says, is 96-percent ethylene glycol, which provides the freeze protection, and four-percent additives. How and Why You Should Check Transmission Fluid.

Dex cool mixed with green coolant