Is GM Dex Coolant really bad?

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Thread: Is GM Dex Coolant really bad?

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    Is GM Dex Coolant really bad?

    I was doing some reasearch on the computer about the Dex coolant system and found out it produces problems for people, my 1996 Lumina has this problem and I want to know if I should take it and get the coolant flushed right away.

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    Re: Is GM Dex Coolant really bad?

    What problem are you having?

    Have you changed your coolant? Dex needs to be changed every 5 years or 100,000 miles.
    DO NOT ADD GREEN COOLANT to Dex.

    In regards to Dex versus other coolants, it is much like a Ford/Chevy arguement. There will be two camps and lots of fighting back and forth.

    A little more info would help.

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    Re: Is GM Dex Coolant really bad?

    Pretty much every independent mechanic will recommend that you get rid of Dex Cool as soon as you can.

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    Re: Is GM Dex Coolant really bad?

    I'm pondering changing out my coolant as it's reached 60000 miles which i believe is the life of dex cool
    Should I have a full flush done when I switch?
    I'm pondering switching to Sierra antifreeze (safer for pets, etc...)

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    Re: Is GM Dex Coolant really bad?

    I was reading this last night, a page about Dexcool by one of the administrators at bonnevilleclub.com. This dude has over 20k posts...

    http://www.zillamotorsports.com/DEX/



    Dexcool. These gaskets were from 2001 and had 30-40k miles on them



    Without Dexcool. These are from a '95 Bonneville with 120k some miles

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    Re: Is GM Dex Coolant really bad?

    I have gotten rid of the Dex Cool coolant. Thank you for your help

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    Re: Is GM Dex Coolant really bad?

    I noticed when Dexcool isn't kept to the proper level and an air gap is left at the top of the radiator, it tended to crust up more than the green. Anyone else experience that?

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    Re: Is GM Dex Coolant really bad?

    There are 2 things you need to know about Dex Cool. The first is never add green coolant to Dex Cool, it will break down the Dex Cool and you will have a bad day. The second is that you have to keep your car full, don't let the coolant level drop. Green coolant leaves a film behind that prevents rust Dex Cool doesn't so if you have any air in the system you will get rust. Another thing is Dex Cool is officially rated at 100,000 miles but I'd change it before then. I change mine around 40-50k but that's just me.

    If you want to get rid of Dex Cool it shouldn't hurt your car to make the switch but be sure to flush out every last drop of Dex Cool from the entire system(radiator/engine block/heater core), you don't want it mixing with the green and gumming things up.

    I personally still run Dex Cool for the fact that the car had it in it when I got it and I don't feel like flushing it out and changing it. I can't really say how it effected my gaskets. The only gasket I've replaced is the one on the water pump when I replaced the distributor but the water pump gasket wasn't an actual gasket, the mechanic who replaced it a long time ago used some sort of liquid RTV gasket maker on it instead of a normal gasket.
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    Re: Is GM Dex Coolant really bad?

    Bought a 99 Cutlass new with the 3.1L and around 60,000 miles I had to replace the head gaskets. They were replaced with a different aftermarket gasket I think and Dexcool is still in it and no more problems. It has 150,000 or so on it now and running fine. I was thinking it was the OEM gaskets that somehow wern't compatable with the Dexcool. I don't know. But I do know that the Dexcool has not eaten through the replacement gaskets in the last 90,000 miles. So I guess if it is the Dexcool I am on borrowed time. I guess I will find out eventually.
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    Re: Is GM Dex Coolant really bad?

    The shop I worked at replaced many lower manifold gaskets. We put Felpros in and had no comebacks. Dexcool and all.

    If Dexcool is the real issue, why are the other engines not listed?

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    Re: Is GM Dex Coolant really bad?

    Quote Originally Posted by Craig L View Post

    If Dexcool is the real issue, why are the other engines not listed?
    Cause dex is not the issue. Bad intake designs/installations were. Properly maintained (hard concept for some) is the key here. Dex is good for up to 5 years/100K miles. Key word is up. Just like the regular is up to 3 years.

    If it calls for dex, use dex.
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    Re: Is GM Dex Coolant really bad?

    Dexcool is just fine for my cars. I change it every two years with a drain and rinse and rinse and then fill.

    The zillasport link above has it down to the T. The one chemical in DexCool as it was formulated early had a deteriorating ability on nylon that was used in the gaskets. The gaskets were changed and the organic compound in the DexCool was changed. But many people had some gasket deterioration by that time.

    Also if the system had air in it that increased the deterioration of DexCool.

    So change it every second year or 30-36K miles and keep the system completely full--burp all the air out of on refill and you'll be fine. Don't go by 150K miles or 5 years.

    I checked out the various "mixes with any" coolant formulations on the gallon containers recently and they have the same chemicals listed as DexCool. Check out the ingredient listings now. Several people have sworn that they're going with the alternatives and, well, it's the same chemicals with a different color. That must mean it's good stuff.

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    Re: Is GM Dex Coolant really bad?

    The DexCool settlement appears to be here soon. Info is at

    http://www.dexcoolsettlement.com/

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    Re: Is GM Dex Coolant really bad?

    Quote Originally Posted by GM lover View Post
    I have gotten rid of the Dex Cool coolant. Thank you for your help

    If you are going to change to something else you need to get EVERY FREAKING DROP of DEX out. Dex and the green stuff can react and there have been horror stories about it gelling when mixed (even in small amounts) with other coolants.

    Here is the rub... Flushing is NOT satisfactory. There are so many nooks and crannies in your cooling system that it is next to impossible to get all of the Dex out... The only way that I know is to yank the engine and turn it upside down... Then you also need to yank the heater core, etc etc.

    Replace the Dex every other year like the green stuff and you will be fine...

    Coolant has little to do with MILEAGE... TIME is the critical factor.
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