: when i get the heater core replaced to i stay Dex or go green

01-26-11, 03:35 PM
OK just as it sounds once i do replace the heater core im thinking going green
only reason there is dex in there now is because i forgot to tell my Mechanic to use green not dex
and now from what i hear it would have to be flushed out probably 3 or 4 times in order to get all the dex from the system and even then it might not get it all
so what should i do
when it comes time

01-26-11, 05:29 PM
Use DEX-COOL and exchange it every 3 -4 years. Pup, this has been covered a thousand times: DEX-COOL or good ol' green coolant - you take care of the system with regular maintenance and exchanges or it will come back and bite you in the butt.

01-26-11, 09:15 PM
4 me what i was planning no matter what i use i was gona have it changed once a year in the beginign of Summer each year cause that would be like 35 to 40k every year but is that over doing it ?

01-26-11, 09:17 PM
yes, that is waaay over-doing it

01-26-11, 09:39 PM
Ok so only every 2 years is what would be best for me wich would be about 70 or 80 k question or should i say not go by years and jsut knowing that i drive as much as i do just do it every 50 or 60 k question

01-26-11, 10:03 PM
GM says 5yrs or 150K (i think... someone correct me if i'm wrong)

many think that is too much time...

if i was you and wanted to be careful i would just do a 3 year cycle

01-26-11, 10:32 PM
5 years and HG's are already rusted half way out with Dex. I have seen this first hand. No longer than 2 years max with dex in the system. Coolant is cheap, HG's are not. Even with the green stuff, I require a 2 year change interval to maintain the 5 year head gasket warranty. I prefer the green.

I tore my 98 STS engine down about a week ago. No carbon build-up (for some reason :D) and the rings were free. HG's were fine. No damage or corrosion. I ran dex in it for the first year, had a heater hose blow and switched to the green. About 2.5 years I had those HG's in that engine. I see no issues down the road, even putting a 5 year warranty on HG work I believe I have very little to worry about and will not have many comebacks, even in the final warranty year: provided the cooling system is maintained as Sub mentions-

01-26-11, 10:38 PM
To each his own opinion.

Every year= excessive and unneccessary
Every 2 years = my recommended change interval
Every 3 years = the limit IMO
Every 4 years = really pushing it
Every 5 years = GM's recommended.

My 2004 Bonneville GXP's HG's looked pretty bad and very rusty. And I did the work in Dec/09. 5 years (+ a few months likely, forget the date of manufacture).

Dex may have been reformulated at some point and may have been improved, but after what I've seen from both green and orange, green all the way for me. But like I said, to each his own.

01-26-11, 11:01 PM
so is orange dex the only thing it does is just last longer and have difrant acids in it ?

and green doesn't last as long but has more acids in it or something i am confused about that

the reason im worried is how many times would i need to have it flushed in order to make sure all the dex is out since i don't wana mix dex with green and then what about the radiator possible anything could be stuck in there that wont come out and then maybe get mixed in i just don't wana get these screwed up by mixing

01-26-11, 11:24 PM
Don't get confused about anything --------run either green or DEX and change it every 3 years in the spring. Problem solved.

I did my DEX in 11/07 and did it again in 11/10. The fluid that drained out looked exactly the same as what went in 3.3 years ago.

01-27-11, 07:13 AM
And Sub still has no problems with his HG's :) :thumbsup:

Maintenance and fluid changes can make a world of difference. It can be the difference between replacing head gaskets, or an entire engine, and not doing anything at all to it-

01-27-11, 10:17 AM
awesome thanks guys this helps me to decide and all better gona stick with the Dex this way also in case i ever go to a dealer for work or if i forget and slips my mind to tell the shop not to use dex cause i have green then they mix green with dex and ill be screwed
so this helps and all

another question was Dex just designed to last longer ? what is it that makes it called Dex Cool is it designed to run cooler also question or is that just the name they slapped on it question

01-27-11, 10:31 AM
I believe it was mostly for the 5 year/100k mile change intervals. It won't cool the engine any differently than the old green. Dex came out in the mid '90s when the engines were just about all running the 100k mile platinum spark plugs. So with the Dexcool, GM could claim "no scheduled maintenance for 100k miles..."

With the green stuff GM spec'd changes every 2 years or approx 30k miles.

I do my green coolant every autumn, and also the Eldo I change the Dex every year (overkill, but it was probably never changed in the first 7 years...). My cast iron LT1 '96 Chevy had the the Dex done maybe once in its life... but that's apples and oranges.

Rippy, you're right about the new cars @ 5yr/150k miles. That must have been a recent change from the old 100k mile spec.

01-27-11, 11:37 AM
yeah i think someone corrected me recently on that... i had said 100k and they told me no 150k ... i felt a bit dumb