I saw a prior posting that Dex-Cool isn't all it's hyped to be. I checked the Internet and found the bottom line about Dex-Cool is the following:

change coolant every two years no matter what type of coolant you use;
flush the cooling system well when changing from green antifreeze to Dex-Cool;
check coolant regularly for changes in color (due to air exposure).

It's been my experience with my 240 bricks (1 year in two cars) that the temperature gauge is lower since I have been using Dex-Cool. However, I had to change my Dex-Cool after a year in one brick because the coolant changed to brown and didn't float all 5 balls.

Am I missing anything?

We just had to replace the rads on 6 trucks (150's and Rangers) due to the Orange County service shop replacing the Sierra brand coolant with DexCool at the last routine service.
6 months later all had major rad damage (rot) and we had to swap out all the water pumps. The thermostats looked like a blob of frozen Orange Crush and it took 3 to 4 hours of run time on the Power Flusher to clean the crud out of the block on each truck.

The clue was when the Temp Sender began to take an inordinate time to register warm up and when we had a lower hose failure due to object impact damage the cut developed a "stalagtite" of DexCool ooze...

Anyway the stuff is "not good" as Martha the soon to be con would say...

You might want to do just a bit more research on the stuff.
check out:
http://www.dexcoolcase.com/
http://www.geocities.com/b_gillie/dexcool_problems
and many others.
I've had to fix a number of dexcool related problems on customer cars .The GM cars that came with the stuff from the factory suffer the worst.That brown stuff will eventually clog the whole system,
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-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel

Just a couple more anecdotes - nothing scientific...

A little over three years ago I went on a flushing binge, putting the Dex-cool by Havoline in everything. Everything then was three NA 240s. A year or so later I began reading some of the scary stuff about its eating gaskets and solder joints - even aluminum on 960s I think? Just left it in, no problems.

Then I had a sudden-loss-of-coolant experience, thankfully not catastrophic, where the thinnest portion of the paper water pump gasket seemed to have dissolved to mush. Red coolant squirting out. Ahh - blame the red coolant, because of course I did excellent work installing that coolant pump.

Red coolant got booted from that car, but I believe my practice of coating the gasket with red silicone, and too much at that, was the reason, not the coolant. I think now the gasket slid out of place while tightening such that only a small amount remained between the pump and the block. It lasted a year and 20K miles before breaking.

Then I read (Steve Ringlee kept a close watch on this topic) something authoritative sounding to the effect that the red coolant was really designed to be compatible with modern cars and not recommended for older cars. So I've just been using green stuff since, but still have red in two cars, well past the two year flush time.

I see traces of it around the expansion tank pressure cap, but other than that, no problems.
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Art Benstein near Baltimore

I have had the same (positive) experience as you, and that with running DexCool for more years then you.

Likewise, my temp guages read just under half.

What is also true, soon after converting over from the green stuff, the Dex Cool seems to loosen up a lot of gunk from the cooling systems. I believe this is why it is recommended that it be cganged every two years.

At least I'd change it within the first two years of installing it. Maybe one year, if I am seeing sludge and debris in the overflow bottle, as I now have in my boiling-over 740 turbo.
--
"Can't understand why people abort Volvos, either"

Dexcool works fine with several caveats:

1. You neeed to keep the coolant level above "minimum" in the reservoir bottle at all times.
2. Dexcool does not do well with soldered brass radiators.
3. You still need to change it every two years if the car was not built with Dexcool installed.

Hey, Steve...

Is the Nissens rad a problem with DexCool? as far as the soldering goes, I mean?
--
"Can't understand why people abort Volvos, either"

OK, my ONE data point is as follows: I replaced my OEM radiator in my 90 745 with a Nissens brass/solder unit (all metal). I replaced the Dexcool. Within a year, the solder joints began to leak. So I chucked the metal radiator and replaced it with a Volvo OEM aluminum/plastic unit. Put back the Dexcool. Zero problems three years later.

Dexcool does a fantastic job with one exception: on soldered radiators. So if you replace your radiator with a soldered unit, use another coolant.

BTW, I just switched one of my 95 940s to Zerex G-05 (the new hybrid with a little silicate). We'll see what happens. So far, it performs just like Dexcool, running cooler at the temp gauge.

Personally, I can't attribute any trouble to Dexcool, although that isn't necessarily a great measure of whether or not to use it. I've been using it for a _long_ time and haven't had any problems related to it. I have noticed that my coolant remains red for the whole time I use it, although I generally change it out one time per year.

Dexcool got a bad rap for a few reasons. First, the very cars it was designed for, General Motors cars, were the ones with the worst problems. They experienced problems often associated with gaskets (defective) that allowed air into the system, and allowed coolant levels to fall below acceptable, or at least optimum, levels. As a direct result, Dexcool was turning into brownish mud and eating away/clogging cooling systems.

Second, there was some discussion about it's effects on lead solder radiators, which seems to be a good reason not to use it in those units.

Third, it seems to find leaks where there might not have been any previously. I always can spot a reddish color at the ends of hoses and once in a while, a little orange stain where it has shown itself around the seams of the radiator or elsewhere, but I have never had any measurable leak over the course of a year, so I have to believe that it is still a reasonably sound replacement coolant. If you flush regularly (the radiator, I mean) you'll have decent luck with Dexcool. If you tend to let it go for a long time without flushing, any coolant is bad, and if it runs at a less than "min" level, it may even be bad for the cooling system. Just a few things to consider.
--
a Brickboard.com Expat

Good to see you contributing again.
--
Art Benstein near Baltimore

Coincidently, Toyota also uses a red coolant. But me dealership tech/neighbor tells me it is not DexCool, but some propriatary coolant.

He also says to keep using Toyota brand in the Avalon.

How could I dispute him, since ther seems to be no aftermarket equivalent?
--
"Can't understand why people abort Volvos, either"