Is there any reason to switch? Does the Dexcool, run any cooler than the green stuff?

 

Dexcool is for later model cars. In the hayns manual it gives you the specific years to run Dexcool. I know my 86 requires Regular

 

Don't quote me on this, but I thought I remember reading that Dexcool came from the factory starting in 96 (?).

 

There was a lot of discussion about this a while back. You may want to do a search on the subject. The short of it is that it does not do as good of a job as does the old green stuff in terms of either lubrication or cooling. The summary of the forum wisdom is that you are better off running green with the highest percentage of distilled H20 you can run in your area. Thats because water cools best but you need freeze protection and for those of us with aluminum heads and cast iorn blocks, we need the very best in corrosion protection. And the rest of the wisdom suggests that you change it frequently. After having to replace my head gaskets because of corrosion, my coolant gets reqular attention. :cool:

 

A lot of headaches can be avoided if you stay w/ the factory stuff. The switch can be done, but you have ot know what you are doing.

 

A couple of years ago a flushed my 90 vette and truck and replaced each with Dexicool. The main advantage of Dexicool is that is not as abrasive on the water pump seals and is supposed to last longer. I'm always for trying new stuff.

A month or so ago I discovered that my truck's coolent had jelled! :eek: I did a thorough flush and replaced with the old green stuff. The vette is fine, no sign of any problems, so I left it alone. Not sure why it jelled. It did not seem to overheat at all.

 

Jelled orange stuff is caused by not getting all the green stuff out. (Flush not good enough.)

One of the risks of switching.

 

Had never heard about the abrasive quality. :confused: GM developed Dexicool for longer life - 5 years 100k vs whatever it is for the green stuff. I have heard that the jell phenomenon results from orange and green mixing. I have Dexicool in my truck and and wife's car; both are been ok. Have green in my 89 vette. I think mixing the two is the problem. :D

 

I have an article on "Red" vs "Green". Can e-mail if you like?

 

They started the Dexcool late 95 for what it's worth. I would stick to what came with the car originally.

 

What he said.

 

When he say's abrasive, I guess he refers to water pump failure. An element of the green stuff is being blamed for water pump failure. I think it was the phosphorus.

FYI: Green or Orange stuff is there to prevent boil-over as well as stop corrosion. May people forget the last part,...... Use the correct amount, regardless of your climate zone.

 

DexCool and Green are both ethylene glycol based, the difference is the additive package (about 10%). DexCool uses an Organic Acid corrosion inhibitor while ‘green’ uses a silicate additive. From a cooling perspective, the two are identical. Lubricity, I would guess DexCool has a slight edge.


Actually the two can be mixed according to Texaco! The benefits are lost, but no harm should come from the process other than reducing the life expectancy to two years.

The "gelling" seems to be caused by a series of events with DexCool. First it seems there must be air in the system and heat. Speculation is rampant on what occurs next, but best guess is cavitation at hot spots combined with sealing tablets and perhaps some rust picked up in the system. Anyway, state change occurs and DexCool becomes what some folks have coined "DeathCool". It can be nearly impossible to clean once this happens.

Always run DexCool full with a new pressure cap and no leaks in the system. GM recommends the overflow level should be at "full hot" when cold.


Nope, see above!

Lou, I would very much like a copy. pcluscombe@luscombe.net

It’s the silicates in ‘green’ that are said to increase water pump seal wear. DexCool does not use silicates, so they advertise reduced water pump seal wear. They may be right. I don’t know how significant the difference may be.

Anti-freeze increases the boiling temperature by about 10*F. Water boils at 212* at 1 atmosphere, a 50/50 mix of water and AF boils around 222*. The 15psi pressurized cooling system is what extends the boiling point to 265*F.

GM/Texaco recommend to never run DexCool below 50/50 concentration Not sure why, but would not take any chances.

Couple other notes:

GM does not recommend using DexCool in pre 94 cars. Personally I agree with the post above that recommend not using DexCool in a car that did not come with it.

Texaco informed me that if the pH falls below 7.0, the DexCool should be flushed.

A positive spring pressure vacuum valve pressure cap should always be used with DexCool, these are not common and may not have come with the car. Stant makes a couple versions, and GM makes them now as well.

If DexCool is used in an engine that came with ‘green’ the life expectancy is reduced to two years.

If DexCool is mixed with green, the life expectancy is reduced to two years.

DexCool must be in contact with a surface to protect it from corrosion.

‘Green’ silicates "plate out’ on to the surfaces of the water jacket, radiator, heater core, etc., and will provide protection from corrosion even if the coolant is not contacting the surface.

The useful life of ‘green’ is two years.

I run 60% distilled / deionized water and 40% green in my 89. And it is flushed every two years, if I let it go that long.

I run 50% DexCool to 50% water in my 99 truck. It has been flushed 3 times so far; once the dealer said it "failed" the test (when I started trying to find out about DexCool), once it failed my pH test, and once during warranty engine maintenance. GM has a neat machine for this flushing, which is quite impressive and quite costly for the person paying for the flush.

 

'96 plus came with it.. only 94-95 can switch from green stuff to dexcool.

 

:nono:

My 95 came from the factory with Dexcool... it had a supplement added to the owners manual stating the change half way through the production year and specificed not to use the green stuff.

 

Me personally, I had one of those bad experiences with dexcool in my 97 camaro after Jiffy lube changed my coolant. Man at the dealer told me it was because someone at the jiffy lube must have mixed some green in there even though that article says you can mix it, this is what I was told. had one heck of a time cleaning the jelled sludge out. Changed it over to green after this experience, never had another problem. :yesnod:

 

Lou, I'd like to read the article too- bcsmith4@unity.ncsu.edu Thanks!

 

salicitate = sand

Ron

 

I'd like that article too. jmec@cswnet.com

 

I put the orange stuff in mine, seems to be fine but would appreciate the article as well, thanks.
michael.harris@rayisd.com