Dexcool No Longer GM Factory Fill!!!

[toocrazy2yoo]

You kept the same hoses on it for 170,000 miles? I just replaced mine this past thermostat changeout, but not because of what was going on inside, they were just hard and dull on the outside. Inside, however, clean as a whistle. Rubbing my fingers up inside where the coolant travels left no black residue on my finger (sort of an informal blotter test)and no "balling up" of the wall of the hoses.

Go figure?

 

[Ray H]

toocrazy2yoo, I especially appreciate the testemonial from a fellow Hyundai owner. I have an '03 Sonata V6. It's green factory-fill coolant had just turned a tad turbid (cloudy) when I drained and flushed the cooling system multiple times with distilled water a year ago September ('04). I refilled with SuperTech Extended Life concentrate (an unlicensed DEX-COOL clone) in the system that already had about a gallon of leftover distilled water in it, and have had no problems, but there was always a question in the dusty, cobweb-clogged back corners of my mind whether this stuff was really, really safe for Hyundai's engine gasket materials. Sounds like my all but unconscious concerns were unjustified. I've lost less than a pint over 1 year and three months, and that was probably normal evaporation through the summer months. (Had nearly a full month of 100+ F. days.) I figure I'll change it out, though, next spring before the hot weather again sets in. I have a jug of G-05 on hand for my ride's next coolant enema.

By the way, what happened to your water pump? Or was it merely a prophylactic replacement during the timing belt replacement? How did the impeller look?

 

[toocrazy2yoo]

Brand new. The radiator is eight years old, has 158,000 miles, give or take, and IT is brand new inside. It only took me two years to put 60,000 miles after the last time I changed it. I always have em change the water pump every time they do the belt, and also the tensioner every other timing belt. Together, they cost less than a hundred bucks, and Fairfax, Va Hyundai never has charged me labor to install them, just for the parts.

So, if the Dex-Cool is a happy experience for you, why are you changing? Lots of these announcements being made today. I tell ya, if your cooling system is tight, your cap is good, and the engine is good at expanding and contracting from a full recovery tank, I have NO idea why you'd change. The transitions and tampering with the vehicle all the time strike me as causing a much greater risk of trouble than a once-yearly flush using the same coolant as has been working for you.

Someone mentioned awhile back in this thread that if a coolant causes trouble in a car with crummy maintenance, THAT in itself is trouble with the coolant. I'd be willing to bet that if you run the radiator low with GO5, or Standard grade Prestone, or even plain tap water, you're going to leave evaporative residue behind.

This "I have to get the Dex-Cool out" thing sounds like a fad. Think I'll sit tight with what I have. Good luck with the new stuff!

How ya like the Sonata?

 

[Ray H]

As I indicated, I haven't had any trouble with DEX-COOL in the Sonata. I also used genuine licensed DEX-COOL (Texaco) in a '96 Accord over four years (whoops...) and the visible core tubes stayed bright-shiny clean the whole time. DEX-COOL's good stuff in my book, too. I'm just a bit more impressed with G-05 the more I read about it. The hybridized formula has OAT and reduced silicates for dual corrosion protection in the event anything damages the OAT layer in use. Silicates "repair" corrosion protection layer damage almost immediately. OAT layering takes several thousand miles to fully re-establish. I certainly didn't mean to discount our mutual experience with DEX-COOL, though. I'm of the opinion that people who've had "problems" with DEX-COOL actually had other problems that DEX-COOL can't mask. But it's easier to blame the antifreeze than admit to poor cooling system maintenance or inherent gasket and intake manifold material problems. GM puts sealing tabs in the radiators of most engines it currently builds. That suggests to me the company is cheaping out with a kludge to avoid instituting a proper fix - just get as many of the dogs through the warranty as possible and stonwall owners who have troubles while still within warranty... ("Gosh, Sir, what did you do that caused all this extensive cooling system damage? Boy, that's gonna cost ya'...")

Only problem in 3 years with my Sonata was a defective domelight switch at delivery (replaced under warranty). It's still rattle-free but trades some handling prowess of the Honda Accord for ride comfort. I have the 2.7L DOHC aluminum V6 - so far, so good, mechanically. Decent fuel mileage (32+ mpg @ 75 mph highway, 21+ mpg in urban crawl), smooth, quiet, and starts as soon as the first cylinder fires - cold or hot. The transition between automatic tranny shifts is generally exceptionally quick & smooth, though the first 2-3 upshift when cold is sometimes a bit crisp. Overall impression? My '03 Sonata so far has been reliable, comfortable, economical transportation with just enough style thrown in to make it look a little upscale. (I love pulling up next to X-Type Jaguars just for the dirty looks I get from their high-maintenance matron drivers - life can be sweet - even in the slow lane!)

 

[thrace]

I have read statements that when a dexcool vehicle has a cooling system failure, it is due to lack of maintenance or a leak. However, if a system and chemicals in it are not tolerant of faults, then premature problems will occur. Imagine if an airliner or a car brake system had only one hydraulic system. In real life, they do not have just one. If it were in perfect condition, it would work perfectly. But real world leaks can occur even if all regularly scheduled inspections are done. Fault tolerance should be designed into a system and the chemicals in it.

 

[Ray H]

Enough intelligence to know to routinely check the coolant level in the radiator* weekly should be a requirement, but realistically, never will be. The good news is that the idiots who can't be bothered to routinely check on their radiator fill level get to learn the hard way. (And the economy has no trouble supporting radiator shops to accomodate these people's folly.

) Modern society has largely become sufficiently lazy that it demands no-fault insurance in every aspect of daily life. Baloney - things just don't work out that way.

*NOT merely the overflow bottle - pinhole leaks in the connecting hose can and do occur.

 

[kev99sl]

I just don't get all the DexCool bashing. All the (admitedly anectdotal) evidence I see says it is in all ways superior to every other coolant I've had experience with. My Saturn has nearly 250,000 miles on the stuff: only replaced the water pump once, and that because of a bad bearing. Coolant changed once in that time. (Not flushed, mind you, simply drained and refilled.) My wife's Civic, on the other hand, has had all the hoses and the radiator replaced at barely 150,000 miles, with all recommended maintenance done at all the recommended intervals. All the other GMs of the same vintage and running DexCool in my life have had similar results. And, while I haven't replaced the radiators in all of the other non-Dex cars I maintain, I have seen a lot more deposits, crud, nastified hoses, bad caps, etc. than I've experienced with any of the cars running DexCool. I think DexCool is a victim of a poorly designed cooling system in a few GM cars, that likely would have been trouble regardless of the coolant used in the application.

 

[Ray H]

One thing for sure - bringing up the subject of DEX-COOL on BITOG has the same effect as waving a red bandana in front of a bull...

 

[raaizin]

I would like to share my experience with Dex-Cool. In a word fantastic. I put it in my 96 explorer 4.0 in '98 (I am original owner) After 5 years drained and replaced with some more dexcool. Car presently has 156k miles on it. I changed the hoses when I did the 2nd drain and fill. This was at @143K. I cut each hose open and it was literally like brand new. I have the origianl water pump also, dont know if it is normal for a 4.0 waterpump to last that long. Who could argue with these results. I maintain my vehicles but would not consider myself fanatical by a long shot

 

[Kestas]

quote:

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G-05 ("HOAT") may well turn out to be merely a transitional brew to cash in on the hysterics that DEX-COOL was to blame for GM's faulty new intake manifold and cylinder head gasket technology from several years back

---

I don't think that's the case. Mercedes has been using this formulation for many years (at least 10). Maybe some older Mercedes owners can pin the exact number of years the manufacturer has been using it.

Conversely, I'm pleasantly surprised that a coolant formulation that used to be specific to Mercedes is now widely accepted for use on most vehicles.

 

[Ray H]

Mercedes has used G-05 for over two decades.

 

[Buford T. Justice]

Well one thing is for sure; Dex-Cool and G-05 are better than the old green conventional engine coolant. I believe Mercedes has used G-05 since ~1984. GM has used Dex-Cool since ~1995.

Conventional green engine coolant has silicates and phosphates. Dex-Cool doesn't have these. G-05 has a very small amount of silicates. Silicates protect surfaces very quickly. The organic protectants take time to start coating the inside of the cooling system, but once this layer of protection has formed, it appears to work quite well.

The Mercury Cougar used Dex-Cool from 1999-2002 when the Cougar was discontinued. This is documented on page 72 at this link...

http://www.fcsdchemicalsandlubricants.com/fad/pdf/catalog.pdf

Both Dex-Cool and G-05 are marvelous formulations. This idea that GM switched to Dex-Cool to screw their customers over on cooling system repairs is stupid. I am pretty sure all manufacturers add the protection tablets at factory-fill.

GM and the other American auto makers knew that the time had come to switch from the conventional green engine coolant they were using up to ~1995 due to consumer demand for a longer life engine coolant. My guess as to why Ford and Dodge use G-05 is probably due to licensing & money. Why should they pay GM for their engine coolant? I would bet Zerex cut them a **** of a deal on G-05.

I don't think Dex-Cool eats gaskets. A lot of the 4.3L engines used in the S-10s had crappy plastic head gaskets that were accidentally over-torqued at the factory which caused them to eventually crack. There may have been a recall (I cannot verify) on these head gaskets which are suppose to be metallic now. You can even use Fel-Pro gaskets which I believe are made out of cork.

Another thing on the S-10s was the original radiator cap. They use the weighted close/open valve design radiator caps. Stant makes the 10320 radiator cap which uses a spring-loaded valve. It is a vastly superior design as compared to the factory one and costs about $4 at any Advance Auto Parts store.

It only takes about 20-30 seconds to check your coolant overflow tank to verify it is at the required fill level and then to take off your radiator cap to verify your radiator is also full of engine coolant then to put the radiator cap back on.

For my family's GM vehicles, I like to use the Zerex 50/50 Dex-Cool for top off if needed since it is mixed with distilled water. Since switching my 1998 Ford Mustang GT to G-05 over 6 months ago, it has NEVER needed to be topped off with more coolant. I do have a 60/40 mixture of G-05 and distilled water both in the Mustang and in a left over G-05 engine coolant jug. I think the coolant is only as good as the water used so I use distilled water with my coolant.

My only complaint about G-05 is that it is so clear-colored. I wish it was dyed green since Zerex claims it is the direct replacement of conventional green coolant.

I think Ford uses a more intelligent design in regards to combining the overflow tank and the radiator (overflow tank being only way to fill the radiator as well) as compared to GM which uses a separate overflow tank which has a cap to fill it connected to the radiator through a small rubber tube with the radiator also having a cap to fill it. I am basing that statement comparing my 1998 Ford Mustang GT to my family's GM vehicles which are a 2003 Chevy S-10 and a 2004 Chevy Blazer.

 

[johnd]

I too, have had pretty good luck with Dexcool. When I got the Camero in 2000, the Dexcool had three years on it and was still clear but a little weak in color so I changed it. In a 5.7 one half of the coolant drains out if you use the radiator drain or bottom coolant hose an half stays in the block. In order to get the other half you pull the knock sensor on the passenger side and a bolt hidden under the frame on the driver side. After pulling and replacing that bolt once I vowed not to repeat it and lose another four hours of my life. I now drain out the half that comes out every two years and fill back up with Dexcool/distilled water. This has turned out to be an excellent compromise. I monitor the Ph and in two years the Ph has usually dropped from about 9 to about 7 and the change brings it back up. I pressure test the cap every season to see if it is still up to snuff. I'm glad my Dexcool story continues to have a happy ending.

 

[occupant]

So far I've gathered three things from this topic.

1) Dex-Cool doesn't like mixing with air either from a leak or from an empty overflow bottle.

2) If kept clean and full, Dex-Cool will last as long as it is intended to.

3) OEM GM radiator caps are crap.

So my 164K 1997 Lumina which appears to have clear clean Dex-Cool in it, and very little mud formation in the overflow bottle, should benefit from regular bottle checks and a new radiator cap?

And my wife's 117K 1998 Lumina which has green coolant and a sludgy radiator cap and a very muddy overflow bottle, should benefit from a complete flush and a new radiator cap? But should I put Dex-Cool back in it or keep the green stuff? it appears to have had issues before with the Dex-Cool from the light gray sludge on the inside of the radiator cap and neck, so stick to green to avoid further buildup?

 

[occupant]

What exactly is that gunk on the underside of the radiator cap? Silicates?

 

[Ray H]

Rather than conventional green, might consider Zerex G-05 as replacement. It's a hybrid of OAT chemistry and reduced silicate content.