orange coolant?

[Boog]

My recently purchased 2000 GMC is my first to come with the ol orange coolant in it. I guess it's dexcool. I noticed the coolant recovery tank was stained inside making it hard to see the coolant level but didn't give much thought to that buildup elsewhere in the system. The truck runs normal temps just fine but now that the mornings are a bit cooler I sometimes need a warm defroster. Not even close. Luke warm air with temp knob on full hot. I first thought it had good coolant flow in and out of the heater core but after starting it cold today and monitoring the heater hoses I found hot water going to the core but very little coming out the return line. I popped both hoses off and first backflushed the core and large chunks of brown mudlike substance came out with some small flat hard particles in it. I reversed the flush several times until all that came out was clear water. Hooked the hoses back up and I have good hot air now.
Knowing there is that junk buildup in the system do I dare to use a brand name flush to remove all I can and go back with the conventional green coolant?
Many years ago I used a two part Dupont cooling system flush. It got the inside looking like new but the next day the water pump went out. I know, it was just time for it to go out anyway. Now with this newer one I don't want to go down that road.
Any suggestions on whether to flush and go back green or flush and go back orange or top it off and leave it be? Thanks.

[JohnC]

GM had some issues with the DexCool coolant when it first came out. It was great from an environmental stand point, but if your system got low it would eat it up fast. I would suggest flushing the system. When you totally get rid of the DexCool you can go back with the old green antifreeze. You just can't mix the two. Several of the companies now have the antifreeze that will mix with either one. That is something I would consider. Just for convenience next time you need to add a little, and don't have one or the other. Hope this helps. I had a similar problem with a 00 Grand Prix that I had. Opened the radiator cap, and it was all muddy looking. So I had it flushed, but they did replace it with the DexCool, and I just made sure and kept an eye on the level of it, and never had a problem.

[truckdude239]

i see thesse vechiles all the time with dexcool it was a great coolant when serviced propley every 5 years or 100k mile WHICH ever came first. me i just flush it out and go with green coolant

[Boog]

I know I can use plain water and run it through until it comes out clear to get rid of the dexcool, though some recommend using only distilled water to flush with. I wonder if the Prestone Super Flush is worth trying? I'd like to get as much of that mud out of there as possible.

[truckdude239]

i've use the stuff they seel at advance auto parts don't remember the name but it worked well i'd pull the thermostat out and flush the engine block with clean water also

[68C15]

GM had the insight to install a stop leak addative when the truck was new. it hardens when exposed to air. normally this is not a problem. until you get even the smallest amount of air in there. air goes to the top (heater core) and the stuff sludges up. I am guessing you had water pump gaskets go bad (extremely stupid design IMO). I am investigating some different type gaskets for my customers.

[special-K]

Go green,Dexcool sucks!! It`s great as long as oxigen doesn`t mix with it.Hmmm...this is the planet Earth,right?We exist because of the level of oxygen here,right?As long as your GM is on Earth I`d say something that mixes with oxygen is a good choice.I`d use a flush or even pay or a purge to get the gunk out.The gunk "is" Dexcool.
My`99 ZR2 didn`t go near 100,000 miles before that crap started fuddling everything up.And,i never had a leak.

[68C15]

plus Dexcool contains a plasticiser (compound that attacks and softens plastics).
case in point; 2 identical cars
1995 Century 3.1, green coolant
1996 Century 3.1, Dexcool

the 95 still has the original intake gaskets and not leaking after 135,000 miles. the 96 (also about 130,000 miles) has had the gaskets done 3 times now and the manifold repaired twice. both have belonged to the same company since new. both have the same gaskets.

[Spray-Bomb]

Like said, Dexcool is crap

Flush it & put good ol green stuff in it

[BIGphillip79]

Any you guys ever hear of or try Evans water less antifreeze. I used in my big rig and loved it. It has a boiling point of like 400 deg and because its waterless no need to worry about corrsion or cavitation of air bubbles. The best thing I like is you can run a no pressure system so I didn't have to worry about my gaskets. I got better mileage with cuz I ran the truck hotter, diesels run better warmer. Bad thing is its like 30 dollars a gallon. My big truck used like 12 gallons but I wrote it off as an expense. I know some guys are using it on dirt cars, but any a you guys try it.

[Gray Ghost]

I prefer the old school green stuff....another vote for the flush!