antifreeze

[EdH]

Anyone replaced the infamous Dexcool with real Prestont type antifreeze? How's it working?

[Ketch]

Originally Posted by EdH

Anyone replaced the infamous Dexcool with real Prestont type antifreeze? How's it working?

well....this is not an answer to your question. And sorry to jump all over your case here but I'm really alarmed at how many people still keep chasing this ghost.

And so here is a warning to all those who keep misleading people into this error of "fixing" DEXCOOL with the old style coolant.

After reading about some people thinking DEXCOOL itself was to blame for some problems, I seriously thought about switching when I fixed a manifold leak. That was over 5 months ago. But I have not had a problem EVER with Dexcool. But still I wondered why there were some issues. So I read as much as I could and even called Havoline, a licensee of DEXCOOL.

Long explanation but basically I came to the conclusion that, like most sophisticated technology these days, a little care and precision was required to make it work correctly. The problem is not DEXCOOL, the problem is user error.

And here's why....the problems experienced by some with Dexcool are easy to reproduce. Here what you do:

Don't drain all the coolant out of the engine.
Don't flush the engine.
Don't replace the thermostat.
Don't replace the radiator cap.
Don't clean out the overflow tank.
Don't correctly (and precisely) mix 50/50 Dexcool and DISTILLED water.
OH and don't use distilled water in your coolant mix...



I have not had any problems with Dexcool. Here's what I DID do:

I pulled the block drain plugs to get ALL the coolant out of the engine. Filled up with water and ran the engine until thermostat cycled a couple of times. Repeat draining via block plugs and radiator drain. Let engine cool off.

Purchased a cheap $7.00 green 6 gallon water container from Wal-mart, (made sure to Sharpie marker it with "COOLANT") and used a painters quart mixing cup to get exactly 50/50 mix of coolant and DISTILLED water. This enables you do have the entire 5 gallon batch mixed properly. Have six gallons and you can top up as needed as the air works its way out over a few days.

For the simple minded here, that's 6 gallons: 3 gal containers of DEXCOOL and 3 gal containers of DISTILLED water.

The manufacturers recommend fresh, DISTILLED water. For less than $1.25 a gallon, its a bargain.

.................................................. ........................
PLEASE DO NOT PROMOTE UNSUPPORTED, UNDOCUMENTED, UNTESTED so-called remedies for largely rumoured, unSUBSTANTIATED issues with Dexcool. There is little true evidence to support the issues with DEXCOOL. It is more likely that regular green antifreeze will cause problems down the road.

DISCLAIMER: I am not a current or former GM or related employee nor are any of my friends, relatives, associates or pets. I have no vested financial interests in this issue. I just tend to trust that hundreds of engineers, some with pHd's, and millions in research dollars is a safer bet that "oh, just try the old coolant....seems to work approach"

[EdH]

Ketch;

Thanks for your reply. From what I read, you are right on with the causes of the problems. However, in todays world it seems that a lot of "sophisticated technolegy" is only to make something work better in the beginning. A short term - short sighted improvement. Down the road the maintenance associated costs are higher. Parts, labor and the price of fixing it to make it work well long term also add to the bill.
It seems that the manifold design on the Vortec seems to be a major contributor of problems, but Dexcool has to share the blame as well. Let's be realistic here with a simple comparison of the two A/F's and why I refuse to use the stuff.
First off, why replace parts that don't need it? Again...extra maintenance costs. In 25+ years of using Prestone I've only replaced a radiator cap ONCE! NEVER a thermostat just because I was changing coolant.

Here where we live we have clean water. We drink right out of the faucet. Water out of the hose goes into the radiator....no extra trip to store to BUY water for vehicle...(seems humurous)

No need to go through extra pain to drain block. After draining radiator, one can tell about how much water is left in block and add enough "green" to get pretty close to the desired mixture. It doesn't have to be exact. Actuallb better that way if you want to adjust your mixture.

Down the road, if the cooling system should become low, (which by the way DOES cause a sludge build-up with Dexcool because of a reaction with the air in the rad., one would need to get a gallon of the orange stuff (oh, and don't forget to BUY some water too) just so you could mix up a batch to top the radiator off. Why not just add some water?

Sooo, in order to make this "sophisticated technolegy" work, it seems that much MORE work time and money is required to maintain it. This extra expense will far offset the longevity of the Dex. and potential problems it can cause.

One more thing. As far as unsupported comments; in all the years that the green stuff has been around, I don't remember EVER hearing a fraction of the issues with it as I hear about Dexcool the few years that it's been around. So I can safely say that the "regular green antifreeze " will NOT be more likely to cause problems down the road.

Thanks again for your reply. It seems that this ghost really DOES need to be chased some more so as to get the best solution on the table. Not that mine is the best, but I explained why I prefer the green and I know it's not a bad choice.

[digithead]

You are forgetting some good stuff. Research and engine design. "old stuff" is just that, old. WHen engines weren't mostly aluminum!! Now that they are the manufacturers use DEXCOOL for a reason, to prevent corrosion. Its not a gimmick. Its called "low phosphur/sulfate" content. THat is not good stuff on aluminum. You SHOULD stick to DEXCOOL in these motors as recommened in your manual. Also, water. Distilled has low mineral content. Thats a good thing to. Your tap water may be 110% safe and clean, but it still can be "hard" water with minerals. For $3.75 why would you not give it the best? The truck sells for over $40K and you wont spend $3.75? No sense to me for sure.

[EdH]

Actually we don't have hard water. Very low on minerals and absolutely NO reason to "buy" water. Yes todays engines may be designed for better efficiency, but obviously not all designed for quality and/or longevity. Change my a/f every two to three years and have rarely had a problem with corrosion. Nothing that a system flush doesn't cure.

[digithead]

I wouldn't so much worry about the water, as you say, if yours is definately not hard. But the engine does need low sulfur/phosphate content like DEXCOOL.

[Delta Dart]

Many GM vehicles had stop leak pellets added to the cooling system at the factory and in the case of my 94 Caprice the factory service manual calls for the addition of two sealant pellets when refilling the coolant system. These pellets guickly turn Dex-Cool into sludge.

I flushed the cooling sytem in the manner Ketch described(had to pull knock sensors to clean out block) and refilled with Dex-Cool minus the pellets and am happy to report no problems, no sludge.

My question is why did GM put this heater core plugging crap in the cooling systems of new vehicles?

[digithead]

Wow, I have never heard of any manufacturer putting in pellets at the start! Planned to leak? For what its worth, I belong to a large BMW newsgroup, where all swear by Dexcool or its equivalent and its all we run in our cars. I will grant you though, we survived MANY MANY years just fine on good ol' Prestone, but then engines had much more steel and less aluminum.

[EdH]

Well, you people are starting to convince me to lean towards the Dexcool, but my 96 Sub. shop manual also says (after flushing radiator) to be sure and add stop leak pellets. I will definitely use D Darts method and go without the pellets. One more thing that I'm wondering. Does any of the other manufactures put Dexcool in their new vehicles? Thanks for all your replies. ALL opinions are what makes these boards work.

[Regency Burb]

I was told the stop leak from the factory is to seal the plastic tanks to the radiator. Since they can't be welded, they were crimped on with an o-ring type seal. a little stop leak to seal the leaks as they appear. Don't know if its true, but it made sense to me.

[digithead]

I do know that DEXCOOL is very common in many GM vehicles.

[MarioM]

Originally Posted by digithead

Wow, I have never heard of any manufacturer putting in pellets at the start! Planned to leak? For what its worth, I belong to a large BMW newsgroup, where all swear by Dexcool or its equivalent and its all we run in our cars. I will grant you though, we survived MANY MANY years just fine on good ol' Prestone, but then engines had much more steel and less aluminum.

GM has used "pellets" for decades -- take it for what it's worth. NEVER use these. They are old technology and WILL cause problems. Bar's Leaks has
newer technology and has proven itself. I'm sure other brands are just as good.

The comments about the Dexcool and aluminum are true. I have read and been advised that newer vehicles that use Dexcool may have sensor problems if the older "green" stuff is used in its place. The lifetime quoted for Dexcool is a fairy tale -- change it sooner and clean the system and no sludge will accumulate. AND, the thermostat is a periodic service item. They wear and eventually stick with disastrous results. For the few buck, why take the chance?