My 1999 GM Astro Van is a Lemon

I love my van. It's a 1999 GM Astro with serious power, seats eight, and took us across the country from Connecticut to California over a year ago. For a full-size van, it handles beautifully, and it has great pickup. So I was heartbroken when six months after we bought it from another military couple, it started overheating. And overheating. And overheating.

I know a little bit about mechanics, so I went over the coolant system carefully. Filled radiator -- check. Leaks -- none. Seals looked fine. The pump seemed to work okay, though my heat didn't work well and I knew that was a sign of a radiator problem. Finally, at a loss, I took it to a mechanic.

He quoted me $1200. !!!

The problem isn't in the van, though. It's not even in the coolant system. It's the coolant itself.

The Evil of Dex-Cool Antifreeze And Why It Will Make Lawyers Happy

This is dull, but bear with me. Antifreeze was first introduced to cars in the 1920s as a way to prevent engines from overheating and locking up; previously, coolants had been either plain water or air. Traditional antifreeze is ethylene glycol. The bright green color you see is actually a dye placed in the antifreeze to tell you that yes, this is antifreeze and it will kill you if you drink it. Antifreeze is supposed to be mixed with water at a 1:1 ratio in order to work properly, and must be maintained at the recommended level to keep your coolant system healthy.

Dex-Cool is different from other antifreezes. It is an Organic Acid Technology (OAT) antifreeze, and the manufacturer claims it has a life span of 150,000 miles -- which is at least half through the likely lifespan of the vehicle. But it has some issues. It is easily contaminated, for one thing; if you put anything in to dilute it besides distilled water OR if you expose it to air, it will turn into goo. Goo is not good for your car's engine.

Dex-Cool is colored pink or red, not green. But when it starts reacting in its transformation to goo, it actually turns a nasty dense orange-rust color. If you think you might have this problem but aren't sure, just go take your radiator cap off. It should be reasonably clean on the bottom. If instead it is coated with a muddy-rusty substance, you probably have the Dex-Cool problem.

Upon turning sludgy, this antifreeze gets into all the little gaskets and valves of your coolant systems. The first thing to go is usually the pump, sometimes the filter. But these won't be the last. In GM vehicles, the primary problem seemed to be the gasket, and that's what most of the class-action suits pending are looking at.

Yes, class action suits. There are several filed in the United States and another in Canada. One suit has reached a tentative agreement in Missouri, and though details have not been hammered out, it looks like it will cover only people who had manifold gasket repair work done within warranty and before July 2003, for certain GM vehicles where the lower intake manifold gasket was made of nylon/silicon.

Is This Enough?

I don't think so. We bought the van after 2003, but the mileage was still within warranty. The Dex-Cool was contaminated when we bought the van, so it wasn't our fault. The lower intake manifold gasket is definitely a problem, but the whole coolant system is contaminated with this now, and there is nothing that can fix it permanently except replacing the whole system.

So, probably, I won't get a taste of the class action settlement. No big deal; with the limitations, I don't see anyone coming out with more than a few hundred dollars. But -- I still love my van. So what I will do is go in and get a complete flush, now that I understand the whole problem. Then I will have it filled with NON-Dex-Cool antifreeze, diluted more than is recommended because hey, I live in Hawaii and I'm not real concerned about the freezing part. Then I will drive my van until its health problems finally kill it, hopefully in a couple or three years and no sooner.

If anyone reading this is considering purchasing a GM vehicle, check the antifreeze before you buy the car. What color is it? Look under that radiator cap just in case to see if there's any gunky buildup. If it's OAT antifreeze and you don't think you want to take the chance, don't buy the car. Also, ask the dealer if the car is one manufactured to use OAT. If it originally had OAT and now has green antifreeze, I'd bet that it is due to this problem, and unless the entire coolant system has been replaced, you have a chance of getting clogs in the future.

If you have an OAT antifreeze, I further recommend that you NEVER do anything to it yourself. It is a delicate balance sort of thing; if the dilution is off or if you use nondistilled water, you can set off the reaction that will create slime in your engine. Always take it to a certified mechanic that you trust, and always get the receipt and keep it with your other important car papers. GM's lawsuits may be settling up, but I suspect there are more lawsuits over OAT in the future.

Check the Resources section of this article for a link to the tentative class action settlement.