Coolant

[bradyjames]

I drive a 2005 Tahoe z71. I Have about 160k miles on it.

What coolant should I be using in it? I know it calls for dex-cool but I’ve read on other GM and Chevy forums that it’s bad and eats away seals and gaskets over time.

So when I bought it I put in a new radiator and water pump and filled it up with Peak 50/50. I haven’t had any issues with it. It’s been running great for the past year and it looks just as clean as the day I put it in.

Recently, I had a small leak. Turns out my thermostat housing wasn’t tightened down to spec. That was my own fault. My mechanic noticed that I was using the wrong coolant though and mentioned that I should be using dex-cool - so here I am lol. He claims that GM has a new dex cool formulation that doesn’t eat away at seals and gaskets and recommended that I switch.

Is there truth to this? Should I stop using Peak 50/50 and switch to the new dex cool?

Any insight or wisdom would be much appreciated.

Thanks

 

[HiHoeSilver]

I drive a 2005 Tahoe z71. I Have about 160k miles on it.

What coolant should I be using in it? I know it calls for dex-cool but I’ve read on other GM and Chevy forums that it’s bad and eats away seals and gaskets over time.

So when I bought it I put in a new radiator and water pump and filled it up with Peak 50/50. I haven’t had any issues with it. It’s been running great for the past year and it looks just as clean as the day I put it in.

Recently, I had a small leak. Turns out my thermostat housing wasn’t tightened down to spec. That was my own fault. My mechanic noticed that I was using the wrong coolant though and mentioned that I should be using dex-cool - so here I am lol. He claims that GM has a new dex cool formulation that doesn’t eat away at seals and gaskets and recommended that I switch.

Is there truth to this? Should I stop using Peak 50/50 and switch to the new dex cool?

Any insight or wisdom would be much appreciated.

Thanks

Yes, there is a new formula. The problem was it's tendency to go acidic.

Truly, any coolant has a finite service life anyways, and should be changed accordingly. The green vs orange debate will be mostly opinion. Just don't MIX them. Pick one, flush the system well, and go for it.

Full disclosure, I run Dex.

 

[OR VietVet]

Dex here too. I would stick with the new Dex formulation.

 

[bradyjames]

Where can I buy the new dex at? Any parts store?

 

[Fless]

Where can I buy the new dex at? Any parts store?

Yup. WalMart, any autoparts store, ranch store, etc.

 

[bradyjames]

I think I will make the switch. Not to sound like an idiot, but is it possible to buy the wrong dex? Do they still stock the old dex formula on shelves or is it a fool proof grab lol.

 

[HiHoeSilver]

I think I will make the switch. Not to sound like an idiot, but is it possible to buy the wrong dex? Do they still stock the old dex formula on shelves or is it a fool proof grab lol.

As long as it says DexCool on the bottle it will meet the GM spec. The old stuff is long gone. Avoid anything that says "universal" or "add to any color."

The only other thing to watch is if you buy pre-diluted or full strength. You will pay about the same for each bottle, but much less for the distilled water to double your volume.

 

[Fless]

Agree with @HiHoeSilver. I don't know if the formula has changed recently (doubt it), but if you're worried about it buy from a store that has good traffic, meaning they turn over their product relatively quickly. I looked at the AC Delco site and the GM Spec is GM 6277M if you care to look for that on the bottle. That should be Extended Life, something like 5 years / 150K miles on the label.

 

[OR VietVet]

Definitely none of the old mix still around. Get the specs for the current mix, like Steve said, and can double check at RA for the Dex-Cool listed there and buy it at a store or auto parts shop you trust. Follow all directions to the letter. Distilled water mix is the best so if the numbers are close, like Nate says, the pre mix could be the way to go. Is there a shelf life difference between pre mix and full strength?

 

[Doubeleive]

dexcool or equivalent, flush it annually. I don't care if they say it's good for 5 years that's just asking for it. It's not like it's a high cost maintenance item, better safe than sorry....