| [GMCnet] Using DEX-COOL antifreeze [message #134844] |
Sat, 16 July 2011 15:57  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Someone recently asked me if they could use Dex-Cool in their GMC. I told them not to use it and gave them the following information that I had once saved.
First, the cooling systems on all older cars have at one time contained traditional phosphate/silicate blends of antifreeze. Thus silicate and phosphate residuals will remain in the cooling systems and continue to break away from surfaces, crevices, and tight areas, entering the new DEX-COOL coolant solution. DEX-COOL is not designed to properly disperse or keep these materials in solution. Therefore, they will seek and adhere to the hottest surfaces within the cooling system, forming scales and deposits. Since the hottest areas are the locations where the greatest amount Of heat transfer takes place, they are the worst spots to have deposits that impede heat transfer. The result is a dramatic affect on cooling system efficiency and performance. Also since corrosion is most likely to occur under deposits, using DEX-COOL could affect long-term corrosion prevention.
The second problem with using DEX-COOL in infrequently driven vehicles concerns the completely organic character of carboxylates in DEX-COOL which make them very good long-life corrosion inhibitors. Unfortunately, being organic, they are consumed by some types of bacteria. The bacteria feeds off the carboxylates, using them as a nutrient, so the corrosion protection that they offer disappears and creates, a potentially serious corrosion problem. This is not a problem in daily drivers whose cooling systems regularly operate at temperatures of over 170 deg F., where the carboxylate consuming bacteria cannot survive. However, it is a problem in vehicles not driven regularly or stored during the winter months.
Finally, in some cooling systems, DEX-COOL may interact with internal materials. For this reason, a recent service bulletin from GM specifically states, “DEX-COOL may be used in 1994 and later Buick models for improved water pump seal performance. It should not be used in 1993 or earlier vehicles because its chemical ingredients interact with internal copper-soldered joints.”
The bottom line is that by using a carboxylate-based antifreeze such as DEX-COOL in a system that contains residuals from the old antifreeze, you could actually do more damage than good. The best approach is to use a traditional antifreeze, the type the system was designed to use.
ALSO, be sure to change your antifreeze ever two years. The anti freezing characteristics of the product are still go after two years but the corrosion inhibitors, antifoam agents, rubber swell additives and water pump lubricant contained in the original antifreeze will deplete over time. It might last longer than two years at times but play it safe and change it anyway at two years and you won't have problems with it.
Emery Stora
77 Kingsley
Santa Fe, NM
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| Re: [GMCnet] Using DEX-COOL antifreeze [message #134874 is a reply to message #134844] |
Sat, 16 July 2011 21:46  |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
Karma: 1
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| Quote: |
Someone recently asked me if they could use Dex-Cool in their GMC................................
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Emery, When I read the labels on several brands of Dex-cool it clearly indicates that it is only recommended for certain late model vehicles and not all makes. Bottom line none included any vehicle manufactured in the 1970's
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: [GMCnet] Using DEX-COOL antifreeze [message #134897 is a reply to message #134844] |
Sun, 17 July 2011 06:48 |
WayneB
Messages: 233
Registered: July 2008
Location: Ontario, Canada
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| emerystora wrote on Sat, 16 July 2011 16:57 |
It should not be used in 1993 or earlier vehicles because its chemical ingredients interact with internal copper-soldered joints.”
Emery Stora
77 Kingsley
Santa Fe, NM
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Back in 1997 a buddy of mine decided to buy some Dex Cool from a GM dealer (expensive at the time)and use it in the cooling system of his pristine 1984 Pontiac Grand Prix.
Within 3 weeks a new radiator he had fitted was leaking badly, after the THIRD replacement rad I realised the stuff was dissolving or corroding the lead solder .
Even the rad shop that was supplying the Rads didnt realise what was happening, I told him I had read a warning about using the stuff in Hot Rod Magazine though, but he still stubbornly thought the rads were not being made correctly.
Not so long ago I was inspecting a 1973 Lamborghini Miura SV that was filled with Dex Cool, same thing as the Pontiac ,it was leaking coolant from the soldered joints of the radiator.
As for prolonging water pump seal life in vehicles designed to use it, I have seen no evidence that this is the case, they seem to need water pumps changing due to leaking seals just the same.
1976 23' GMCII By Explorer
[Updated on: Sun, 17 July 2011 06:50] Report message to a moderator |
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