dex-cool anti-freeze

[diamondwhite]

Folks,
I am ready to flush and replace the anti-freeze in a 2002 3.5L Aurora.

However, due to the dex-cool issues, I am somewhat reluctant to use this type of anti-freeze.

What type/kind of anti-freeze do most of you use when replenishing your anti-freeze after a flush.

[Marc]

I have been using Dex Cool in my 2001 4.0 since the day I got it almost 5 years ago. No problems in the cooling system so far.

[scottydl]

What Dex-Cool issues are you referring to? The Aurora cooling systems are designed for Dex-cool. Technically you can refill with anything as long as the Dex-Cool is *completely* flushed out... you don't want any mixing with the standard green stuff.

[95rora]

The problem with Dex-Cool that I am aware of is that it will eat your intake manifold gaskets. This happened in my moms 99 suburban and in my dads 00 blazer (actually he got it flushed before it could do any harm). I dont know if the aurora will have the same problem or not. Maybe the Chem E's at Prestone have fixed this problem, but it was a problem with the vortec engines.

[bld]

No problems on either of my '01 Blazers, after racking up many, many miles.

[BNICOV]

That's why you are supposed to change yor coolant. It turns acidic over the passage of time. Stick to the dex cool.

[JimW]

Agreed. Change the coolant regularily, I heard every 50 000 km or 30 000 miles.

As I understand it, Dexcool works far better in all aluminum engines then in combination aluminum/cast iron. You will not have any problems with the longer life Dexcool coolant in your all aluminum V8 engine.

Dexcool was invented primarily to help sell the 100 000km (60 000 mile) first tune up that most manufacturers stress. Higher quality plugs, higher grade stainless steel exhaust components, DexCool etc are all techonological advancements aimed at prolonging mileage between tune ups.

[Aurora40]

I'd also suggest sticking with Dex-Cool, and just being sure to change it at the appropriate intervals.

[auroralover]

Do you guys recommend a flush/fill, or a drain/fill? looking to get mine done in the next week or so before old man winter gets here.

[BNICOV]

Do a flush/fill as opposed to a drain/fill, you will get more of the old coolant out and it will help to flush out any deposits that may have formed. Make sure that the appropriate mixture of coolant/water is refilled. Make sure that it is not normal tap water, distilled water works the best in a cooling system as there are no minerals in it. Go pick up a couple of jugs and bring them with you to make sure it is done properly.

[Aurora40]

Actually, I'm the opposite. I would just drain/fill. The crap should be settled and drain out anyway. I wouldn't want to get tap water or flush solution in the engine and not have it drain out. The system won't totally drain, I'd rather have 50/50 old stuff in those parts than plain mineraly water or some chemical flush stuff.

Edit: there really shouldn't be any crud anyway. It's an aluminum motor, so there won't be any rust scale.

[Aurora5000]

Every January, I drain the radiator and add fresh Dex cool back into radiator. No flushing and it always has fresh fluid and pellets added each year. This was a suggestion from Bbob on the caddy board.

Rad. drain is on drivers side, use upper rad hose for pellets and new fluid.

[blackandsilver]

I have a 2001 3.5----what are the pellets you speak of? Are they something you can get at Autozone? Looking to flush it myself---How many Dex-cool containers fill system? thanks

[Aurora5000]

This is from the Cadillac Board:

I have been asked a number of times about whether you should use coolant supplement pellets with DexCool in the Northstar engine or 4.1/4.5/4.9 engine?


Simple answer: USE THE COOLANT SUPPLEMENT PELLETS REGARDLESS OF
WHICH TYPE OF COOLANT YOU ARE USING.

The coolant supplement/sealer works to seal any microscopic porosity or incipient leak in the coolant system. Internal coolant intrusion is not good for any engine and the coolant supplement is cheap insurance against any internal coolant intrusion.

The supplement should be added each time the coolant is changed. I think the confusion exists because factory installation of the coolant supplement was stopped in the late 90's as it was felt
the supplement was no longer required and added cost and made the coolant system look "dirty". This happened about the same time the DexCool was introduced so people assumed the two happenings were related. This is not true. There is nothing in DexCool that negates the need for coolant supplement , especially in an older engine.
Personally, I use the supplement in every car, snowmobile, tractor,etc. I own and I strongly recommend to everyone to use it as it is very cheap insurance.

The standard green coolant and DexCool are both ethylene-glycol based products. The green coolant has a silicate based corrosion inhibitor and DexCool has an organic acid based corrosion
inhibitor. The silicates in the green coolant get depleted over time and the corrosion protection diminishes dramatically. That is why it needs frequent replacement. The DexCool lasts virtually
forever due to the different chemistry in the corrosion inhibitor. The ethylene-glycol is what give you the boiling and freeze protection. It never wears out but the corrosion inhibitors are equally important, especially in an aluminum engine. Corrosion protection in an aluminum engine is vitally important. Aluminum exhibits a phenomenon called hot transport deposition corrosion...microscopic bits of aluminum break away from the hottest areas (exhaust port) into the coolant and precipitate out in the cold areas of the cooling system (radiator). Cracks result
in the hot areas as stress risers develop. Cracked heads, coolant leaks into exhaust ports and failed head gaskets are common signs of a poorly maintained cooling system where the corrosion
inhibitors have failed. The cold rolled core of the head gasket will corrode from the edges where it contacts the coolant if the inhibitors have failed.

Poorly maintained cooling systems on aluminum engines are common unfortunately because the coolant stays nice and green even after the silicates have depleted and corrosion sets in because the alum corrosion does not "color" the coolant. An iron engine will tell you the corrosion protection is gone because you see red rust in the coolant. Also, the alum engines deplete the corrosion inhibitors more quickly than an iron engine.

DexCool is not designed for 18 wheelers or trucks. Big commercial diesel engines need nitrates in the coolant to prevent cavitation and erosion of the wet cylinder liners. I do not
think any big diesel engine manufacturer recommends DexCool. Any trucker experimenting with DexCool could have saved himself the bother and engine damage by reading his owners manual.
Conversely, because it does not work in a big diesel is no reason to not use it in a gasoline passenger car engine.

If the engine was completely drained and flushed and switched to DexCool that is fine. Continue to use the DexCool but I would still recommend periodic drains and refills. Since the engine was
"plated" internally with silicates from the green coolant the DexCool lifetime advantage is not as effective and it need periodic replacement as it becomes contaminated with silicates
from inside the engine thus depleting its corrosion protection over time. In either case...USE THE COOLANT SUPPLEMENT.

The green silicate coolant has two undesirable side effects that bear mentioning:
One is that the silicates are very abrasive and shorten water pump seal life by abrading the surface of the seal. Also the silicates can build up on the seal surface and "unseat" the seal
causing seepage. The seal is fine but the silicate contamination does cause a leak. The coolant supplement pellets tend to prevent the latter situation by cleaning the surface of the water pump
seal and preventing the silicate build up. The little fibers in the supplement literally "scrub" the surface preventing the silicate buildup. It doesn't seem to prevent erosion of the seal
by the abrasive silicates unfortunately. The second situation is more pronounced in occasional use cars that might also get a higher than the recommended 50/50 concentration of coolant (more coolant than water). The silicates can "congeal" in low flow areas like the heater core forming this
green "jello" that plugs the heater core. The lower the flow, the greater the coolant concentration and the longer the down times the greater the tendency to form the green jello. Usually it can
be flushed out with a strong water flow from a garden hose but it is a pain.
Both of these problems prompted the use of DexCool from the factory as well as the long term corrosion protection compared to the green coolant.

Switching the system over to DexCool will not necessarily give lifetime corrosion protection as previously explained but it will eliminate the two problems above which are worthwhile in themselves.
Neither the green coolant nor DexCool should ever be added straight to the cooling system. ALWAYS PREMIX 50/50 COOLANT/DISTILLED WATER. Premixing is important because you do not want to run a greater than 50/50 mix of coolant. The cooling system will loose capacity due to the lower heat transfer capability of the coolant and lower flow due to the added
viscosity of the coolant. The added silicates in the green coolant are not desirable as mentioned least the dreaded green jello form. The acid DexCool must be premixed as it is very
undesirable to introduce the acidic coolant directly or have a greater than 50/50 concentration.
My personal recommendation is to avoid flushing the system as it ends up introducing plain water and/or flush chemicals which are very harmful (minerals and caustic, respectively) Just drain the
radiator periodically and refill with 50/50 premix. do this once a year and the system is protected as a fresh charge of corrosion inhibitors is always being introduced and the coolant is always
being replenished. Since no Allantes ever came with DexCool it is safe to say that draining and refilling with either coolant would be recommended as DexCool in any Allante will be only partially
effective over the long run due to the inherent silicate contamination.

Several more things come to mind regarding the overall coolant issue. You will see at truck stops a "heavy duty" or "long life" silicated green coolant. NOT RECOMMENDED. Too much silicate
concentration for a gasoline engine. Highly likely to gel and/or cause water pump seal problems. Just as DexCool is not designed for heavy duty diesel use the "heavy duty" silicated coolant is
not designed for passenger cars.

I recommend Texaco DexCool coolant. Texaco developed the stuff in conjunction with GM and is the OEM supplier. Others market a "DexCool compatible" long life coolant but I would recommend the Texaco product. I also recommend Prestone.

Bbob

You can get the coolant supplement pellets at any GM dealer. Also you can find them at war mart in the golden tubes. 6 pellets(GM) or 2 golden tubes. I believe it is Bars Golden Seal.

Will have to check. All that it is... ground up ginger root. You install in the upper rad hose NOT the overflow tank.

[Wacko]

Anyone notice the Google ad at the top of this page (well, it was there when I read this thread)?


Dex-Cool Investigation
Dex-Cool corroding your GM engine? Coolant leak, gasket problems?

I didn't read it but thought it might be relevent.

[oldsauroraman1]

diamondwhite said:

Folks,
I am ready to flush and replace the anti-freeze in a 2002 3.5L Aurora.

However, due to the dex-cool issues, I am somewhat reluctant to use this type of anti-freeze.

What type/kind of anti-freeze do most of you use when replenishing your anti-freeze after a flush.

The issues with Dex-Cool were several years ago and they have been taken care of. It's very safe to use now.

[1997aurora97]

As others have stated definatly use the Dex-Cool it is recomened at the dealer . I would also recomend a flush and fill at least every other time or if you go over on you mile intervals. The dealer also told me that you no longer need the pellets the new Dex- Cool already has the additives in it.

[Aurora5000]

1997aurora97 said:

As others have stated definatly use the Dex-Cool it is recomened at the dealer . I would also recomend a flush and fill at least every other time or if you go over on you mile intervals. The dealer also told me that you no longer need the pellets the new Dex- Cool already has the additives in it.

I have never heard of Dexcool with the pellets added.

Have you, Bob?

[Aurora40]

aurora5000 said:

1997aurora97 said:

As others have stated definatly use the Dex-Cool it is recomened at the dealer . I would also recomend a flush and fill at least every other time or if you go over on you mile intervals. The dealer also told me that you no longer need the pellets the new Dex- Cool already has the additives in it.

I have never heard of Dexcool with the pellets added.

Have you, Bob?

No. I'd imagine they'd settle out. Plus, you don't want to add the sealant stuff to the surge tank. I suspect this is just another dumb service/dealer guy. When my dad bought Dex-cool so I could drain/fill his to address minor leaking (pellets fixed the problem, it was a small drip from porousity), the service guy told him it was pre-diluted.

If I hadn't read the bottle, my dad would have used it straight. Of course it was not pre-diluted, my dad bought twice as much as he needed, and he would have probably ruined his engine if he'd used it undiluted.

Read the bottle, and believe only what it says on it. Service people and dealership folks are generally idiots. Not always, but the majority of them. Thankfully the mechanics are usually competent.

[Wacko]

I know a guy, one of the precious few who works at a dealership that is quite competent. He first worked at a Cadillac dealer so, he would have some expertise here. I'll drop him an email. I tend to be skeptical too regarding coolant with pellets already added.

He then went on to work for a Dodge dealership. Now he is with Chrysler-Jeep. He just picked up a Dodge 2500 with the Hemi. He has like a one-mile commute. What a tease it must be to have all those ponies yet such a short ride.