G12/Dexcool compatibility test......best way?

[wavinwayne]

I want to know what will happen if VW G12 coolant is mixed with Dexcool. From reading previous threads, it appears that the only difference between the two is a very slight difference in the PH#. In my thick wooden skull, this means the two coolants should be perfectly compatible.

If I simply mix equal amounts of each into a container, will this tell me if they are ok to mix, or would I have to conjure up some way to simulate an operating condition? I guess what I'm getting at is that the two might appear to mix fine in a container, but might seperate, gel, spontaneously combust, etc. when put into service.

My indy VW mechanic swears that the two coolants can not be mixed. I just want to see if he's right or wrong.

Any input is appreciated.

 

[Mickey_M]

Basically nothing will happen.

Mix the two in a jar and let it sit for a week or a month.


.

 

[wavinwayne]

Mickey_M,

Are you saying that nothing will happen because the two coolants ARE compatible?

-OR-

Are you saying that nothing will happen because the two coolants are just sitting there?

 

[Ray H]

I believe Mickey_M's saying there's no reason to believe terrible things will happen inside your car's cooling system with that combination since the two products' chemistries are so similar as to be considered the same for all practical purposes.

 

[Audi Junkie]

"My indy VW mechanic swears"

That's the LAST person whom you want advice on this from. Those guys swear everything has to be by-the-book. Ask him a few technical questions about the ingredients and his reference material on his answer and he (or she) will decend into some "seen it happen" or "common sense" retoric without having the facts strait.

Honestly, if I had a car with G-12, I'd be more than happy to put in 1/2 G-12 and 1/2 Dexcool just to prove a point. Read my previous post more carefully, some coolants carry both G-12 and Dexcool recommedations....for a reason.

quote of myself...

"For topping-off, Dex is fine as a temporary boost to the G-12. However, low coolant levels indicate there is another problem that must be looked at. Also, air is getting into the system, a know glop-producing problem with these types of ORGANIC ACID TECHNOLOGY coolants.

[thus the assumption that Dex has somthing to do with the glopping, because the owner had low coolant levels with air leaks in the rad seams and coolant expantion tank and topped-with whatever was handy ...in an already failing system, so later the tech finds the glopping and blames the mix itself]"


The whole mixing coolants thing is just paranoia and ignorance.

 

[ebaker]

I thought G12 was more similar to G-05 than Dexcool

 

[Ray H]

Might wanna invest in one of the antifreeze concentration testers like the pointer type from Prestone. I'm running SuperTech's version of Prestone All Makes "prestone" in my Hyundai V6 - made by Prestone for WalMart - and the temp gauge reads exactly the same as it did with the green-snot-of-death factory fill fluid. Another possibility is that there's an airlock in your cooling system. Is there a bleed screw or special "burp" procedure described in your GTi's owner's manual?

 

[brettpep]

I don't know about MIXING G12 with Dexcool but I'm running Prestone All Makes All Models (Dexcool) in my 1998 GTi VR6 with no problems. Course I fully flushed the radiator before I switched.

The one thing I have noticed is it seems to run just a tad hotter on the gauge. But it could be my mix is off so it is hard to know for sure.

 

[1pt8T]

There is a bleed procedure for the 1.8T. On most of them there is a bleed hole on one of the heater core hoses (I believe that is the highest point in the cooling system) where you slide the hose partially off with the engine and heater running. When air stops coming out of that hole, you push the hose back on all the way. I used to believe the system would purge itself of air if you ran the heater and drove the car for a bit because of the coolant recovery tank and other areas where air can escape, but I believe you ARE supposed to bleed after water related repairs.

 

[1pt8T]

Do you know if the Prestone tester will work with different coolants? I know VW/Audi has their own tool, but I was wondering if they are compatible between G12 and Dex?

 

[threeputtpar]

You probably won't get an answer from the member that you responded to because this thread is 6 years old, so I'll help.

I have the cheapo Prestone coolant concentration tester and it works 100% in G12.