My 07 just turned 36K. I did my coolant at 35K. Took off the lower radiator hose on the passenger side(thru the wheel well) and pulled a plug in the block on the drivers side(it has a green mark on it).
Got as much fluid as possible out and refilled with the prestone dexcool approved stuff. Lots of discussions on here regarding what coolant to use but I'm using what ever GM recommends until my warranty expires. I'll just change it frequently. Do some searches and you'll find plenty of reading material.
I've also changed out my brake fluid and power steering fluid. I'd do that also...it's not so much the the odometer as it is the time. Oh, one more thing, I did change my air filter even though the guage showed perfect and it only had 35K. It made a tremendous difference.

 

Heron thanks so much for the info,i will go tomarrow and get some prestone dexcool and put it in,again thanks for the help.

 

Moved to Maintenance & Fluids.

 

Since you are only changing about 1/2 of the fluid using the drain method, I suggest more frequent changes. For this reason, I do mine every 3 years or so.

 

Whats the proper way to change all of the fluid?

 

I need to do mine pretty bad, i have pondered on what i will replace it with

 

this is what i read about doing it, very detailed good directions
http://www.dieselplace.com/forum/showthread.php?t=374086

 

If you out of warranty what type of coolant would you all recommend?

 

There has been talk and I have read articles about Dexcool gumming up things like the rad caps and flush tank caps as in our trucks. I talked to a guy who said to flush out the Dex and change over to regular coolant (green stuff). I had to change my water pump so I ended up using 6the Amsoil 750k mile coolant and refilling with that. It comes full strength (concentrate) so you have to mix it down 50/50 when filling up. Now with the Dominator Coolant Boost out on the market I will add some of that in as well. It is great to get heat faster in the cab during cold weather.

 

I put in amsoil coolant, mixed it 70/30. 70 coolant/30 distilled water for best performance results. And I also added 25 ounces amsoil coolant boost. All per amsoil instructions. I can say it does its job, and very pleased with the results. I took it in and had it flushed with a machine. cost me like 60 or 70 bucks. I wanted it flushed good, so Thats why I did it that way. Even the guys at the shop couldnt believe how good the amsoil coolant was. the coolant was expensive, but good for 750,000 miles, you really only have to do it once well worth it.