Dex cool corrosive to Aluminum?

[Diesel Dog]

Speaking with a mechanic friend who has an 8.1 he just picked up brand new. He has a couple hundred miles on it and is replacing the dex-cool with Prestone. His sources have told him that dex-cool, as well as the other vehicle makers long life coolant are corrosive to aluminum. He is going to completely flush the system. Anyone else hear of this? Just though I would pass it on, if there is any truth to it, quick and cheap insurance to flush and replace the coolant.

[Colorado Kid]

My understanding is that just the opposite is true....the primary reason that the long life coolants (red) were created was to better protect alluminum components without the uses of silcates which, while helpful for protecting alluminum from corosion are abrasive and very hard on water pumps. Earlier alluminum friendly coolants had silicates, and earlier "low silicate" formulas were not OK for alluminum. I think your friend has found a quick and simple way to void a significant portion of his warranty.

[Kennedy]

My '96 has 134k on it and has had Dex Cool in it all it's life. I too, have heard horror stories about Dex Cool, but havent had seen any problems personally.

What I have observed is that in the presence of oxygen, it can be very corrosive, but then again, so can conventional glycol.

I once pulled the upper rad hose on my '96 to swap out thermostats. The next time into it, the housing was pitted where the Dex cool had been in contact under the hose. ALL internal surfaces were just fine. Quite a few 6.5's lost the heater QC nipple in the thermostat housing. Many several times. Once again, I think they weeped a bit and the Dex cool/air got to them from the pipe joint. I now use dielectric grease (I suppose plumbers grease would work equally as well) in a thin layer under my hoses, and on the pipe threads of these manifolds. I also run a ground wire from the rad to chassis. IIRC, it was VW that had electrical charge induced corrosin problems??? and found that grounding the rad solved this.

Dennis B (White Truck in the forum) has advised me that his preference is to run the surge tank as full as possible to minimize the amount of oxygen present, and I have followed suit.

[mark45678]

I do agree that the new orange stuff is good for most metals . what I dont agree with is leaveing it in for the 5 years like the OEM says is ok! most of the cooling systems that I have opened up with stuff that old(orange stuff) have lots of crap in them. I say change it every 2~3 years and your head gaskets, intake gaskets ,water pump seals will never let you down.NEVER MIX GREEN AND ORANGE STUFF..... you will get heavy pinkish pudding!!!!! not a good thing.

[CleviteKid]

Ford did not invent Dex-Cool, so they spread rumors about it. Dex-Cool is an excellent coolant, but has to be used properly, in properly maintained cooling systems. I always mix Dex-Cool with distilled water (80 cents a gallon at the grocery store) for best performance and corrosion protection. And I change half the coolant every year.

Dr. Lee

[mackin]

CleviteKid ,

Just wanted to SAY YOU THE MAN !!!!!!!!! I heard those rumors too ridiculous.......
MAC :D :D

[Luis]

DD....If my mechanic said he was going to flush the dexcool out of his vehicle I think I would start looking for another mechanic. Not that I'm an expert but they put it there for a reason and I'm sure his sources are wrong. What about warranty issues?
I'd think twice and hard about that.

[CleviteKid]

Dr. Lee, so you change half the coolant each year, how do you do that, right bank in odd years, left bank in even years ??? And won't it all get mixed together when you run the engine for a year?
You confused me.

The Clevite Kid . . . :confused: . . . tongue.gif

[Diesel Dog]

OK, Ok, guys, don't shoot the messenger. The guy works on my work car. He is a good mechanic, just trying to pass something on that may have been important. Apparently it is wrong. I am glad for that too! Thanks.
;)

[dmaxstu]

I recently had occasion to do bussiness with our local radiator shop, he told me not to use that orange stuff in copper cooling systems, but it was good in the aluminum rads. Which meant I had to re-do my coolant in the intercooler in the boat I had welcomed the infrequent coolant changing in the boat 'cause it's a hassle, but I had better get back to changing it on a regular basis. Stu

[tonkater]

Phil, the service manager at Town and Country Chevy in Kent CT , told me there have been some problems with dex cool clogging the radiators /heater cores solid , and that gm even issued service bulletin about it.(he mentioned Tahoes ) He felt it was an issue of the production line plastic pressure cap not sealing.So perhaps this coolant is very volatle with air.

[Lone Eagle]

Some people just have a hard time with anything new. This is modern technology and has been around for years in industrial applications. Later! Lone Eagle

[ 03-28-2002: Message edited by: Lone Eagle ]</p>

[Wilky]

Coolant/water that circulates pass Aluminum will cause electrolysis/corrosion. This can not be stopped, but can be reduced. Now which coolant is better to reduce the corrosion is the question. Distilled water is better because it is less conductive. I would not worry about this corrosion in relation to the Heads, the effect is very very slow.

[White Truck]

There have been several good comments posted, thought I'd add a couple more. The difference between Dex Cool and regular antifreeze are in the additives. They are both an ethylene glycol base. Some of the additives in the old green stuff were actually somewhat abrasive to the water pump seal, so that is why Dex Cool gives longer seal life. The additives in the green tended to settle out of suspension, Dex Cool additives don't. The significant difference is how the additives behave toward corrosion. The green additives are used up at a constant rate, protecting surfaces against corrosion even if no protection is needed. The Dex additives don't actually do anything until a change in the surface exists, then the additives react with the surface of the metal to prevent corrosion. They deplete at a much slower rate as a result. The only problems I have seen are from poorly maintained systems that are allowed to run low with air in them. They can get rusty and have a lot of build up in the upper radiator and overflow. Of course, regularly checking the cap and maintaining the overflow about an inch above the hot line will prevent any problems. Vehicles that use a pressurized overflow tank with the pressure cap on the tank instead of the radiator seem to have virtually no problems, since there is no regular flow of coolant past the seal.