DEX Cool

[Birdseyeview]

The 912 ULS Operator manual talks about max coolant temps for both "conventional" and "waterless" coolant. I'm planning to use the DEXCool that has been discussed on the forum. Is DEXCool considered "conventional" or "waterless"?

[Dave S]

"Conventional" = Ethylene glycol - normally diluted to 50% like in a car, the Dexcool brand is ethylene glycol

"Waterless" = 100% Propylene Glycol, One brand is Evans

An interesting factoid about propylene glycol is its common use as a food additive

[alexM]

"Conventional" = Ethylene glycol - normally diluted to 50% like in a car, the Dexcool brand is ethylene glycol

"Waterless" = 100% Propylene Glycol, One brand is Evans

An interesting factoid about propylene glycol is its common use as a food additive

Heavily packaged food maybe. Propylene glycol is the active ingredient in bowel prep, familiar to those of us over 50.

[Xengineguy]

The 912 ULS Operator manual talks about max coolant temps for both "conventional" and "waterless" coolant. I'm planning to use the DEXCool that has been discussed on the forum. Is DEXCool considered "conventional" or "waterless"?

I have worked on automotive cooling systems for more than 30 years. In that time I would say the worst
antifreeze ever Is Dexcool
i would recommend anything other than dexcool! GO 5 is a good coolant. Many newer import antifreezes
are great also. Do some more research before you use dex.

[Av8r3400]

I have worked on automotive cooling systems for more than 30 years. In that time I would say the worst
antifreeze ever Is Dexcool
i would recommend anything other than dexcool! GO 5 is a good coolant. Many newer import antifreezes
are great also. Do some more research before you use dex.


Good bad or indifferent, Dexcool is what Rotax specs for and recommends for the 912 engine. Personally, I'll follow their recommendation.

Evans waterless has (thankfully) fallen out of favor. It's not as efficient in heat transfer and is extremely difficult to source in an emergency.

[jiott]

Before you trash Dexcool which most of us have been using for many years without a single problem, please explain WHY Dexcool is the "worst antifreeze ever". We are willing to learn facts.

[109JB]

Most problems I am aware of regarding dexcool result from improper mixing of dexcool and "green" antifreeze. This isn't dexcools fault. I have over a million miles on dexcool without a single issue.

That said, the rotax owners manual I have does not recommend dexcool. It recommends BASF Glysantin or equivalent. Could dexcool be an equivalent? Sure, but there are also several SB/SI/SL s that basically allude to use of "conventional" antifreeze as being ok. IMO, any silicate free and nitrate free antifreeze will be suitable provided they have anti-corrosion properties that are sufficient. Any modern antifreeze should be able to handle this.

The most important thing with antifreeze is don't mix types. Dexcool + green equals gelling and that is bad, but it isn't just green. The colors are mostly just dye, so color doesn't really mean squat. I always use the same brand/type and if switching then the entire system gets flushed completely before putting the new brand/type antifreeze in.

Just my opinion.

[jiott]

John, sounds perfectly reasonable.
By the way, the latest 912 Owner's Manual refers to Rotax Service Bulletin SI-912-016 R11 for coolant recommendations. It lists several US manufacturers in addition to the BASF in their list of approved coolants: Prestone Dex Cool Ext Life, Shell Dex Cool, and Texaco Havoline Ext Life. It also basically says any "conventional" coolant that is silicate and nitrate free is satisfactory.

[Xengineguy]

Before you trash Dexcool which most of us have been using for many years without a single problem, please explain WHY Dexcool is the "worst antifreeze ever". We are willing to learn facts.

Sorry if you think I’m trashing a product. My experience has come from the automotive field.
I have owned a automotive/ industrial radiator repair shop for many years. I have seen the results
of using Dexcool in especially gm products. As mentioned the antifreeze can turn to mud/ pudding.
Also intake manifolds suffered extreme corrosion, aluminium radiators and heater cores rotted from the inside.
Personally I don’t believe that mixing different types of coolant was the cause. Though never recommended.
I believe the cause of the coolant failure was introduction of air into the systems. Over and over.
Systems with good overflow tanks, that only allow fluid in and out of the system worked much better.
At the same time GM was having so many problems one of my customers installed Dex in several
street rods and classic cars. All properly flushed before installing Dex. Two years later what a mess!
None of these cars had proper coolant recovery tanks.
If you can keep the air out, and replace the coolant every couple years you will be ok, maybe.

I have never seen any other coolant cause more problems than Dex.

[JustPlaneMike]

Why does Rotax Rick advise to only use green antifreeze?