DEX-COOL

[GITZY]

after reading countless articles on this crap.i'am concearned about my brother in law's car.last week he bought a 2000 lesabre with only 46,000 miles on it.the car is from arizona all its life until last year when the owner moved to wisconsin.he bought it from a dealership so you would think the dealership would have fixed anything if it was leaking.how do you tell if you have dex-cool in the cooling system.also if it does have it can you drain just the radiator or do you have to do a complete flush to get rid of this crap.what antifreeze can you use in replace of it.

thanks for your input.

[01bonneSC]

Dex is Orange in color. You should flush it and replace with prestone all makes antifreeze and distilled water or the premix stuff.

[ChilinMichael]

Also for input, I prefer to disconnect and flush the heater core, engine and radiator separately. Especially when getting rid of Dex I'd do that, granted "all makes" antifreeze won't give you a problem if a little is left, I'd still play the safe side and get all of it out real good.

[SUSPECT 0]

With only 46,000 miles its probably fine.

You should also drain the oil to see whether or not the oil has coolant in it.

[01bonneSC]

With only 46,000 miles its probably fine.

You should also drain the oil to see whether or not the oil has coolant in it.

Doesnt matter, need to get the dex out. Time is also an issue, not only miles

[SUSPECT 0]

With only 46,000 miles its probably fine.

You should also drain the oil to see whether or not the oil has coolant in it.

Doesnt matter, need to get the dex out. Time is also an issue, not only miles

I meant that the LIM gaskets are probably fine.

[willwren]

Don't count on it. I bet if you pull them, you'll see their condition and be grateful you did it early. The UIM and LIM gaskets WILL fail, and if not caught in time, WILL cost you a motor. We've seen gaskets fail in as little as 20k with DexCool, and UIM failure in as little as 30k miles. It'll cost you less to do it NOW, and if you fix it right, you'll never have to do it again.

[01bonneSC]

With only 46,000 miles its probably fine.

You should also drain the oil to see whether or not the oil has coolant in it.

Doesnt matter, need to get the dex out. Time is also an issue, not only miles

I meant that the LIM gaskets are probably fine.

I know you did, 10 years of sitting in a corrosive solution still does damage.

[willwren]

Sitting is actually worse. DexCool turns acidic when it's exposed to air. When a car sits, the coolant settles and draws in air over time. It corrodes aluminum and gaskets, then starts creating sludge in pockets that don't have circulation.

Read www.dex-cool.net and believe it.

[Bonnefied_GM]

Sitting is actually worse. DexCool turns acidic when it's exposed to air. When a car sits, the coolant settles and draws in air over time. It corrodes aluminum and gaskets, then starts creating sludge in pockets that don't have circulation.

So would I be better driving my Bonneville than letting it sit in the garage until I get the manifold work done? It's supposedly leaking externally right now.

[renchjeep]

You would be best off by flushing the DEX out now, and refill with anything else (I prefer old-fashioned green), and then dealing with the UIM/LIM gaskets ASAP. The sooner the DEX is out, the better! It may save some aluminum parts.

[imidazol97]

Sitting is actually worse. DexCool turns acidic when it's exposed to air. When a car sits, the coolant settles and draws in air over time. It corrodes aluminum and gaskets, then starts creating sludge in pockets that don't have circulation.

I note that the article linked, which appears to be from several years back, mentions that DexCool was reformulated.

When was it reformulated? I suspect it would have been in 1999 or so, about the time GM changed the upper intake design at the EGR to help the problem that was happening.

The 2000 leSabre most likely has the newer DexCool with the updated antioxidant instead of the earlier antioxidant that detriorated under certain conditions.

After reading for years about how terrible the DexCool is, I looked on the bottles of Prestone's Mixes with Any Color and on Prestone's DexCool bottles. They list exactly the same ingredients. So I called technical support and asked what was the difference and I got the answer, to paraphrase, that they were functionally the same.

For the 2000 in question, I would be concerned about the long periods of sitting. I would have the coolant thoroughly rinsed out and replaced either with DexCool or Mixes with Any Color, machts nichts, because I believe they are NOW the same coolant.

For the 2000 I would have the throttle body removed and a new aftermarket gasket put on there to prevent the thin gasket installed by GM from seeping coolant into the air stream. I base that on what the mechanic I had do my upper and lower replacement told me. (I was in a hurry to get it done or I would have done it myself.) He said the original gaskets were too thin after the UIM warped slightly with age or heat against the throttle body and they seep. The recall GM did installing stronger screws to press the throttle body against the UIM harder to help prevent seeps and the adding of sealant tabs during the recall weren't enough: they should have replaced gaskets on the throttle body. The recall may not have applied to the 2000 because they may still have been using the coolant sealer from the factory.

I had run an oil analysis for $25 Blackstone on my used oil after switching to synthetic and they found traces of coolant after 7000 miles. So I was afraid the UIM/LIM had leaks. It turned out to be the throttle body seeping--only. Everything else was fine. That's after 109,000 miles on mostly DexCool. I had replaced it with Mixes with Any Color about 10,000 miles earlier.

So my advice for GITZY is to recommend a used oil analysis to see if there are seeps.
I then recommend asking about the throttle body gasket replacement which is relatively cheap and they can clean the throttle body area while they doing that.
I recommend a thorough rinse of the coolant and replacing with whichever coolant you like.

My lower in take gaskets were in good shape (despite 100,000 miles of that supposedly awful DexCool) and the upper was good. I however was assuming worst case and had the mechanic put in a APN upper with the metal sleeve to protect the EGR passage and metal covered lower gaskets. So the old girl is good for another 100-150K miles.

The $25 oil analysis accidentally found the slight seep--it was worth its price.

[willwren]

In spite of the supposed reformulation, we have seen no functional change in the effects of DexCool. The mixes with any uses a totally different OAT than either formulation of DexCool. Organic acids vary greatly, and are proprietary in design, so you won't be given that information over the phone or by any other means.

[imidazol97]

Prestone All makes All Models etc lists
ethylene glycol
diethylene glycol
sodium 2-ethyl hexanoate
sociium neodecanoate

An old reference to sodium 2-ethyl hexanoate
is
"Do not use Prestone universal in any Taurus. This is an Organic Acid Technology (OAT) coolant. The Prestone "Long-Life (5yr 150,000mi)" coolant contains sodium 2-ethyl hexanoate according to the bottle, which is probably the salt formed from mixing 2-ethyl-hexanoic acid with sodium hydroxide base. From the August 2004 issue of Motor magazine: "All DexCool-approved coolants to date use two organic acid rust/corrosion inhibitors, one called sebacate, the other called 2-EHA (which stands for 2-ethyl hexanoic acid). ....The rust inhibitor 2-EHA poses another issue: It's a plasticizer (softens plastic), so it has been blamed for coolant passage gasket leakage. Softening (and the resulting distortion) was reported by Ford, which encountered gasket leakage problems when it tested a DexCool type formula on its V8 engines. Ford also saw similar issues with other gasket materials. That killed the OAT coolant idea for Ford". Use the Zerex G-05 long-life (Ford specification WSS-M97B51-A1, A.K.A. "yellow stuff") instead which is a hybrid organic acid technology product not based on 2-ethyl-hexanoic acid. A complaint has been filed against Prestone for misleading advertising in the use of the word "universal". One can also use the good old fashioned short-life green stuff and replace it more often. "

Note that this calls the 2-ethyl hexanoate a "plasticizer." It's in the current Prestone Mixes All Types antifreeze.

The sodium neodecanoate is referenced elsewhere as an additional OAT.

The plasticizer is in the Prestone Mixes as well as the Prestone DexCool.

Is there a hidden component in these formulations?

[willwren]

If you search on DexCool formula, you will find references here and there that state proprietary or intellectual property claims to some of the ingredients or amounts. You will NEVER find a detailed and fully accurate formula for any anti-freeze or 'coolant' product on the market.

[imidazol97]

The mechanic who replaced my gaskets refilled with a local auto parts chain's "long life" antifreeze, which is dark green. I'm considering draining and replacing with a recommended coolant.

I was curious then and now about the formulation of that antifreeze and whether it's as effective at protecting the aluminum/iron parts of my 3800 as the DexCool/Mixes with Any Color antifreeze is.

Here's the component list from Prestone for their long life:
Prestone® Extended Life Antifreeze/Coolant (AF-2000)
Ethylene Glycol, 2-Ethyl Hexanoic Acid Sodium Salt, Water, Sodium Hydroxide, Neodecanoic Acid Sodium Salt, Sodium Tolytriazole, Dye, n-Propanol, Polypropylene Glycol.

That doesn't quite match the forumulation on the bottle which has diethylene glycol on it. But this includes Na Tolytriazole, which is a lubricant and antioxidant; normal-propanol, which is an alcohol; and polypropylene glycol.

[ChilinMichael]

If you switched to green from Dex, you better make real sure the system was flushed VERY thoroughly.

[00Beast]

All coolant is Ethylene Glycol. However, not all Ethylene Glycol is the same. It's like reading a bottle of Coca-Cola and one of Pepsi. They both use the same ingredients, however "Natural Flavors" is a HUGE area, and completely changes the makeup of the solution.

Also, why do you think we switch to the aluminum gaskets? Problem solved.

[Bing]

Waiting is like playing russian roulette with a completely loaded gun. It just makes sense to do the preventative maintenance with a dex-cool car. I would just do the whole top end update, like Willwren suggested. Having gone through a motor self destructing, I would suggest taking care of the car now. Just my 2 cents though.

[Bonnevillans]

I recently went to the Pontiac dealer asking about switching out the dexcool in my 02 grand prix with 20k miles. They insisted Not to change out the dexcool as it was reformulated....just make sure to change it every two years not five as it claims....I don't drive the car on a regular basis...any more on the dexcool? I changed it in my 96 bonneville to pre stone with no problems when I did the Uim and lim....