It recently occurred to me that neither I nor my wife can remember the last time we flushed our radiators. We’ve only owned the cars about five years and I know I’ve done them both at least once, but holy cow has antifreeze gotten expensive!
Rather than change them both just because it’s been a while, I sprung for one of those bobbly-needle testers. Both coolants check out just fine, but what’s still bugging me is that the color of the stuff is all wrong. In both of them, the green dye is barely noticeable anymore, and has been replaced by a slight brown tinge in an otherwise clear fluid. Rust, I’m assuming.
I’m sure it would be better to change the stuff than leave it alone, but is it really necessary? The meter says we’re still protected. If I have to change both of these cars it’s probably going to cost thirty bucks.
Prolonged heating breaks down ethylene glycol into glycolic and formic acids, neither of which are good for engines.
If the fluorescent dye has broken down, or the pH has gotten too low for it to fluoresce properly, it is time to change your antifreeze.
*"Indeed, the hike in crude oil prices, the starting point for EG (ethylene glycol), has driven up cost, but China’s increase in textile manufacturing is playing the most significant role…
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In the United States, the largest consumer of antifreeze, demand hasn’t grown in 12 years, says Rightler. This can partly be attributed to longer lasting coolants and longer lasting engines.
The U.S. antifreeze market, which has kept annual consumption at around 200 million gallons a year, represented 25 percent of the world’s glycol demand in the past. But because of China’s ramped up manufacturing climate, U.S. EG consumption now is only 5 percent of worldwide demand. “What’s happening is the Chinese are expanding their polyester business greater than the U.S. and Canadian antifreeze market every year,” he says, adding that China consumes 24 million gallons of antifreeze per year."*
Antifreeze including corrosion inhibitors. The anti-freeze protection doesn’t change (that’s why it’s called “permanent antifreeze”), but the anti-corrosion additives get consumed doing their job. That’s why engine cooling systems should be periodically flushed and refilled with coolant containing fresh antifreeze. Failure to do this can cause premature failure of various cooling system components, and in worst cases can require very expensive repairs. If you think antifreeze is expensive, price a radiator, heater core, or cylinder head.
You have tested the anti-freeze property of your coolant. This is meaningless relative to the need for a flush and fill. If you want to do a meaningful test, test the pH of the coolant. In this case, though, you needn’t bother, as the rust you’re seeing makes it clear that corrosion is already in progress.
I suggest service the cars as soon as possible. Since corrosion is already in progress, double-flushing (first with a cleaning agent, then with water) may be necessary - otherwise the coolant may continue to be rusty even with new antifreeze.
Could we go back to alcohol-based antifreeze? Using ethyl aqlcohol ISO ethylene glycol would be much safer-I shudder to think how much poison is illegally dumped down drains and sewers. since cars all have sealed cooling systems, why can’t alcohol be used?