coolant questions?

[teslagadget]

new to the forum here and just picked up a nice 99 tahoe with 171k. Just had a simple question as ive heard that the vortec 5.7s dont like the dexcool and should be replaced with just regular green. Is this true or not. Also wanted to ask what your tahoes operating temp is. I live out in the desert and it seems that the dealer or the previous owner put a 160 t-stat in. Im thinking they did this as temps rise to 120 plus out here but im sure that the opertating temp needs to be around 190 or so. The temp gauge doesnt move much and is always at about 160 even with the a/c blasting. Thanks matt

 

[clkelley]

Honestly, none of them "like" Dexcool. In the wrong mixture it can be harmful to seals, etc in the cooling system. The green stuff is a little better, although I know of other better options. The only issue with the "better" options is that they cost more, but are environmentally friendly, non abrasive and offer service intervals of up to 250K miles. They also offer more consistent operating temps in all temps and while loaded.

As for the thermostat, I would replace that with a 190* unit. the engine needs to operate at a certain temp for the best overall performance, etc.

 

[teslagadget]

ended up finding a small coolant leak coming from the top oil cooler line so i went ahead and bought new radiator, 195 failsafe t-stat, and 2 gallons of dexcool 50/50 mix. Seems to now run at the correct temp. thank smatt

 

[the baPhoon]

I use only water wetter in both the Tahoe radiator, typhoon radiator and intercooler.
I'm in central az so I don't really worry about freezing. But I've noticed one helluva drop in iats in both trucks.

 

[Woodstock]

Doesnt matter what you run in it, as long as you dont mix it with anything else. Mixing dexcool with the old green stuff will cause it to gel/sludge up and make a mess for you.

 

[Andrew99Tahoe]

When I bought my 99 Tahoe i noticed it had the green coolant. I did some research and I found that a lot of people ditched the dex-cool because itll gum up systems if there is any air introduced to it. At that point itll basically cost a lot to fix it. Although green coolant doesnt have as high as a temperature tolerance, it is more dependable and more common. Adding green coolant to a dex-cool system is a mistake that happens a lot.