I have 170k on the truck (1998 6.5 2500) and have no coolant leaks. My question, is there any danger in switching from Dexcool to the old green stuff or that new use anywhere coolant? I'm planning on flushing the cooling system, changing both radiator hoses and pulling the radiator cleaning everything out before the horse show season just regular maint. I am currently planning an intake gasket replacement on a 2002 Pontiac Grand Prix GTP because of dexcool, I would like to get rid of it if I could, I don’t want any problems with my truck. I was just wondering if any of you guys have had an experience where you switched and ended up with a leak or the new stuff reacted with the old stuff an now have a head gasket leak or something.

I have 170k on the truck (1998 6.5 2500) and have no coolant leaks. My question, is there any danger in switching from Dexcool to the old green stuff or that new use anywhere coolant? I'm planning on flushing the cooling system, changing both radiator hoses and pulling the radiator cleaning everything out before the horse show season just regular maint. I am currently planning an intake gasket replacement on a 2002 Pontiac Grand Prix GTP because of dexcool, I would like to get rid of it if I could, I don’t want any problems with my truck. I was just wondering if any of you guys have had an experience where you switched and ended up with a leak or the new stuff reacted with the old stuff an now have a head gasket leak or something.
i would not use old green stuff. get new green stuff and make sure you flush ALL of the red stuff out. i have heard bad things about mixing the two even in small amounts. Ed

I asked Bill Heath about this when I did my Heath Cooling upgrade. He said green is fine but extended life is even better. I heard somewhere there is a class action suit against GM over dexcool. Your doing a good thing losing it.

Please, enlighten me on why dexcool is a bad product? I just did a water pump on my mom's car (98 trans am) and flushed the cooling system w/ a garden hose (yeah yeah, redneck flush I know...) while i had it apart and it looked great while draining it. I put dexcool back in it and now i'm wondering if i've made a mistake.

I have read about the dexcool law suit to not that long ago I changed everything over to the green stuff to I will look for the web site.

I had a 97 Gmc Jimmy(one of the little ones) with the 4.3 that I had to have power flushed every 7-9 months. The temps would start to slowly creep up on me and I knew it was time to have it done yet again.

From what I understand, a PO must have mixed some of the green and some of the orange at some point. It resulted in a gunk build up and required a flush every so often. Didn't seem to matter how many times I had it done, the gunk would always come back.

I'm not sure if there is any way to 100% clean out the cooling system, switching from one to another, even the stealership I took it to didn't seem to have a sure fire fix for my problem. Just my .02.

What I have heard about the dexcool is that it is supposed to last about 5 years before you need to flush and change it.
The problem is that during these 5 years, dexcool apparently gets enough time to make "red mud" and loose it's cooling properties while getting cooling circuit dirty.

My father in law just shot a headgasket. The cooling circuit was stucked with red mud, completely clogged. My father in law is happy.
He'll be back to green stuff ...

A while ago when I changed my water pump, I found red mud too, and swap immediately to green stuff. I told him, but he was so confident with GM that he didn't believe me.

Now, USA is too far from us, but if he should have the possibility of a trial, sure he would have done. Believe me, I can't tell you his words concerning Dexcool

oh wow, i had no idea. Thank all of you! I'm not real happy it has dexcool in it right now but i dont think it'd be worth it to re-change in case i can't get it all out.

Yes, I think you can keep it inside. Just don't wait 5 years before flushing the cooling system.
BTW, I did flush mine with a garden hose too :D

I believe(not positive on this) the extended life can blend with trace amounts of dexcool without damage.

BTW, I did flush mine with a garden hose too :D
LMAO worked like a champ, huh? ;)

yup :D

I did not see mention of draining the block (block plug behind engine mount, apparently) - IMO you can't really flush until you're dumping at the absolute lowest point. Thanks for the post - perfect timing as I will be doing the SAME thing soon when things warm up (VA warm that is, not Alberta warm).

My wife's 99 blazer came with the dex-cool stuff. About the 4 year timeframe the heater started not working. I had always added any coolant with straight water no mixing of any green stuff. I replaced all the hoses, and reverse flushed the heater core, removed the block drain plugs too and flushed the crap out of it. The heater core was gunked up with what i would describe as "jello" stuff, and the radiator as well. I flushed it until the water was really clear and re-filled with green. No problems since and that's been about 4 years now. From now on, about the 3-4 year mark i'll drain the dexcool out, flush really well and replace with green. No more dex-crap for me.
Don

I read that the dex-cool class action suit was due to its affinity to eat through plastic parts in the coolant system. Resulting in rapid coolant loss and engine overheats and falures.

Our 6.5's have never been mentioned in association with this problem, probably due to the fact that we do not have any plastic parts in our cooling system, or at least none that the dex-cool like to eat.

"BTW, I did flush mine with a garden hose too :D"

Thats the way I did mine, worked great. I even called the city to see where I should safely dispose of my old coolant they told me to let it go down the city drains, they said it was good for the sewer system. I didn't argue as that was also the easiest method of disposal.
They did tell me not to let it pool up anywhere an animal could get to and drink it.

Thanks for the reply's. My plan was to drain all the coolant, fill up the truck with water add flush (Napa brand) and run till warm, drain again. Fill up with water run till warm and drain again. Drain radiator and block drain (if I can find it) pull radiator clean real good, install two new hoses and fill back up with something other than dexcool, probably the all brand coolant from Prestone.

I read on here last year about cleaning your radiator, removing it and actually cleaning the airflow passages. My truck was running warmer than usual so I thought I would try something. I didn't pull the radiator out last year, but I took the shroud off the top and looked down between the radiator and the condenser, man what a mess. I dropped a shopvac down there and got as much out as I could then from the back of the radiator I flushed forward, took off the grill and loosened the oil cooler and the trans cooler, behind them was like a rats nest. This year I’m going to do the job all the way, I couldn’t believe how much cooler the truck ran after I did what I did last year. I never thought about the cooling system getting dirty, but after I pulled 2 plastic bags out and about 4 inches of leaves I find my self paying more attention to every vehicle I look at now. Some of you guys are pretty smart:)

I guess I'll be the guy that says 260000 mi with orange coolant. my heater still works,my truck stays "semi" cool towing,original water pump,etc. I have had a leak for 5yrs at the goofy connector at the tstat but that is the only problem.....

If Dex Cool was "BAD" GM would have abandoned years ago. Vehiciles with the most common problem have air intrusion into the cooling system !! If you read & use the GM info to the letter you will not have a provable DexCool related problem. My opinion backed by facts,not myths. Gm has actually incresaed service interval lengths & is reported to be considering declaring it for the life of the vehicle as standard use. Just think about how long cooling system componets last when DexCool is used as intended.Well' other than the heater hose O ring @ the crossover connector. A common problem for sure!!!

Google DEX cool suits seem to be vehicle specific, and proper PH is part of why it's bad sometimes, along with folks mixing it with green not knowing any better, a lot more to the "rest of the story" kinda like all 6.5s are bad if you ask right individual.

IMO if there is better to do than why not toss the dexcool if there is even a chance ? I have two friends who worked at the GM Dealership and said get rid of the stuff. I flushed mine with the garden hose too but I did it when i was doing the waterpump upgrade so I put the hose right into the waterpump ports. I know I got it all out. It was running nice and clear through every orifice. Heath doesn't use it and that's good enough for me.

I’ve been doing some thinking, cold and ice here lot’s of time on my hands. What kind of coolant is used in a commercial diesel, an 18-wheeler? I’ve heard about cavitations causing pitting in the cylinder liners of a sleeved engine. Has anyone ever had a problem with that in a 6.5? I would assume Dexcool is diesel approved with out an SCA additive to be used in a Duramax right? I was thinking why not flush the system and use whatever coolant they use in a big truck. Like the Rotella Coolant if I could find it, or the Fleet guard brand, or the Motor craft Diesel coolant. What do you guys think?

All of you should be draining you cooling systesm,, every 2 years anyway,,, that way you can take out the radiator and clean it!!!!!! Besides its good practice! LoL

I think why try to "reinvent the wheel"???? Really study the Dexcool. It works as designed in our trucks. Air intrusion into the cooling system is the natural enemy of the dexcool. That was shown by the faulty S10 radiator cap to radiator relationship causing clogged radiators. Bottom line if you educate yourself on how to maintain the cooling system & identify the maladys that happen with the 6.5's propensity to spring leaks you will be likely to become satisfied with GM's coolant choice. Heck man it is installed in ,what 14000000 vehicles manufactured in the US market each year.!!! This group of folks hereare a small percentage of GM owners & there is daily reports here of major abuse done to the 6.5 engined trucks.

http://www.getahelmet.com/jeeps/maint/dexcool/

http://www.getahelmet.com/jeeps/maint/dexcool/


Now that's a pretty good article! Thanks!

Rob :)

Regular coolant + water wetter works perfect for me.

i heard all the horror stories about dex-cool but after running it for 252,000 miles i'll keep using it. I change mine out every 2 years and when the water pump went out at 225,000 miles i put new radiator hoses on and the inside of the old ones were just fine. no pitting or weird sludge everywhere. I replaced the heads due to a crack (big suprise for a 6.5) and the head gaskets were in excellent shape. No problems there. They key here is to change every 2 years or so OR test the PH of the coolant system often and add additives as needed to keep the coolant in check. I'm not yet sold on the fact that its "long life coolant" so i'll keep changing it every few years