what is the best coolant to use in my truck. is it just the gm stufor can i use aftermarket stuff. i am thinking about changing my coolant out. i just siezed a bearing and broke my belt. i figure that i have to put the belt on and why not change the coolant. i have 77,ooo miles and dont know if it has ever been changed. thanks

Use gm dexcool, change it every 5 years. If you do use aftermarket coolant make sure that it meets gm specs for LONG LIFE coolant.

Hey thanks i will just stick with dexcool. i have to pick up my parts at the dealer any way. thanks agian.

My pleasure, use a 50/50 mix with distilled water and the total system holds 22 quarts of coolant, so pick up 11 or so quarts of dexcool if your goning to drain the system completely.

You can normally get dexcool at walmart for a significant savings.

I agree there is no need to buy it at the dealer. I just used Prestone's version last week to do mine. Each Fall I drain the radiator and refiill with fresh 50/50 mix. Draining the radiator empty's 3 gal from the system. In my opinion its much easier than doing a full flush every few years. There is no way I'd go 5 years between changes.

myself I just went to the local speedy lube. It as $70 to have it done, but without the drain cocks, it's just annoying to do on the newer vehicles. Took around 20 minutes and they sucked out the old and put in the new. All is good. For a once every couple of years maintenance, it's just easier to have someone else do this one.