Pulled The Trigger

[Ironhorse]

Well, finally after owning our '99 Tahoe 4x4 LS package for just over 13 years it is no longer in the stable. Traded it in on a 2005 Tahoe Z71 4x4, one owner with 136K on the clock and the 5.3 LS motor. Loaded with many more bells and whistles than our '99 for sure. Will take a bit of time to figure just how everything works, LOL.

It has the leather interior which wife and I are not fond of but nearly impossible to find a cloth interior now days. It had quad buckets and we had them switched out to a center bench. Lift up hatch instead of our cargo doors and it has the third seat. Grandkids you know, LOL. Rides great, on 17s instead of the 16s on the '99. '99 had 218K on the clock, bought it at 66K. Looked for a good long while trying to find something that didn't have a bazillion miles on it. Makes one think folks get in a vehicle and never shut the engine off at all! Time will tell if we will get the same number of miles and use satisfaction from the '05 Z71 but guess it was time to make the move.

Come Spring first thing I plan to do is a complete motor and radiator flush of the Dex-cool and install new fresh green coolant. Not a fan of Dex-cool at all.

[Palf70Step]

Congrats. I am like you, keep the leather and give me a cloth interior. I do miss the barn door style rear too. Good luck with your granny-kids ride!

[hatzie]

Keep using the Dex Cool and keep it full. The green stuff tends to have bad interactions with the seam gaskets at the radiator end tanks among other places. My 1995 GMC went through two radiators before I wised up.
I get the Prestone Dex-Cool premix at WalMart so I don't have to buy distilled water.

I run Dex-Cool in my GM stuff and Honda blue in my Accura. The Green Silicate stuff is for the antiques. Easier to keep track of what's there.

[Ironhorse]

Changed out the Dex-cool in our '99 Tahoe with the 5.7 when had to do the intake gasket replacement. That was nearly 90,000 miles back and never a problem. Only thing I did was put a large printed label on the radiator stating "Converted to Ethylene-glycol" Had been very pleased with the results and never had it turn to jelly.

[hatzie]

Originally Posted by Ironhorse

Changed out the Dex-cool in our '99 Tahoe with the 5.7 when had to do the intake gasket replacement. That was nearly 90,000 miles back and never a problem. Only thing I did was put a large printed label on the radiator stating "Converted to Ethylene-glycol" Had been very pleased with the results and never had it turn to jelly.

It's only the real early Dex Cool formulations that turned to jello but the reputation lives on...
I'd guess that 95% or more of it was people topping off the new OAT Dex Cool systems with "green" IAT Silicate coolants that were in common use at the time.

Converting from OAT to IAT coolant is similar to moving from synthetic oil back to dinosaur squeezins or bolting a carb onto your TBI engine.
It'll work but there's a reason GM started using DexCool, Synthetic oil, and electronic fuel injection... it wasn't to have something exotic in the cooling systems and crankcases and even the early TBI systems really do perform better on less fuel.

[mikelom]

I use Dex Cool also and have no complaints.

[mcmlxix]

!!

[biketopia]

Dex cool got a really bad rep in the beginning because people would let it get low, add whatever to the system and it would react. They saw 100k 5 year service interval and assumed lifetime. If you keep it full, and fresh it will serve you very very well. My duramax has dex in it and it has 180k on the clock and no cooling or antifreeze issues. The engine and cooling system is designed for Dex i'd stick with it, just flush it and get the pre-mixed if you don't want to mess with distilled water.

You're going to be very happy with that truck, my ex and I had an 04 that is still kicking with well over 200 on it. My big thing would be to check the brake lines, if they haven't been done, get prepared for them, it's common on that generation GM truck and SUV. Get a set from the dealer or find the part # and get them on amazon. The pre bent coated lines will last forever and A LOT easier to work with vs the Dorman stainless kits, plus they are half the price.