Author Topic: Dexron Coolant -- be careful at service stations.  (Read 385 times)

Offline goodfellow

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Dexron Coolant -- be careful at service stations.
« on: August 31, 2019, 02:47:01 PM »
Just came back from visiting friends of Mrs GF, and we had a great time. On the way out, our host mentioned something about taking a "quick" look at his radiator. He has a 2015 Malibu with slightly over 100K on the clock and he wanted to change the coolant. Apparently the coolant had become "sticky" -- I looked at the radiator and indeed the stuff was like mud in the upper radiator.

My first inclination was to ask if he's mixed a glycol-based coolant with Dex, and he answered "no" to that question. I've seen Dex-Cool systems develop sludge after more than five years, but never like this. We quickly flushed the radiator and sure enough -- the sludge poured out the bottom of the radiator hose. The radiator seemed to clean up nicely, but at that point the entire system was likely in the same condition. I told him to flush the entire cooling system thoroughly and refill with Dexron. It only took a few minutes of my time, but during the flushing procedure, his wife mentioned that she had been on a trip last year and stopped to get an oil change at a local gas station -- they topped off all the fluids (incl. filling the expansion tank), and I suspect that they mistakenly added regular green glycol-based coolant to the system; which in turn caused this mess a year later.

Be careful -- watch what people add to your systems when you take it in for service. Better yet, educate your wives, girlfriends, family members on making sure the proper fluids go into your modern cars.

Offline slip knot

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Re: Dexron Coolant -- be careful at service stations.
« Reply #1 on: August 31, 2019, 03:14:33 PM »
I drained the red stuff out of my 98 GM as soon as the warranty was up. Even the line mechanic at the dealership suggested it.

Offline bonneyman

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Re: Dexron Coolant -- be careful at service stations.
« Reply #2 on: August 31, 2019, 03:42:12 PM »
Big 10-4 on watching service station attendants nowadays.

I know I had yellow-green coolant (silicate-based) in the Toyota, and orange Dexcool (mineral acid-based) for the wife's car and the van. And you DID NOT want to mix those. >:(

Now with the Toyota gone all I have to worry about is the orange stuff. But then a friend told me they've come out with a new green coolant that's "universal". And I think I saw that some Toyota's have red coolant. I try to stay informed, but geez it seems like coolant is all over the map these

Maybe you could do a write-up on auto coolants, Ray? I'm sure I'm not the only one who's a bit confused.
« Last Edit: August 31, 2019, 03:44:00 PM by bonneyman »

Offline stokester

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Re: Dexron Coolant -- be careful at service stations.
« Reply #3 on: August 31, 2019, 05:13:58 PM »
All the newer models of GM cars use the DexCool and have for many years now without any issue.  During the initial introduction of it there was a problem with the gaskets but this has since been resolved.

Like with oils, this is a fluid best left to the OEM's recommendations, most "universal" fluids are a compromise.
Yorktown, VA