So i e been searching on how to do a radiator flush on my wifes yukon 5.3 flex fuel and i cant really find some good info...i know that i can only use dex cool coolant but does anyone have a step by step on how to go about doing it myself? The truck has 76k miles so its about time...

 

With that mileage your not gonna have much gunk or grime so you could drain and fill.
Or you can unhook hoses and with a garden hose back flush it. Meaning spray into upper rad hose till it comes clean out the bottom then from the bottom spray. Unhook heater core lines and again threw each. Wash out resevoir.

 

I thought the service interval for the new DexCool stuff was like 150K mi.

 

5 year 100, 000mi I thought. It gets so acidic over time and sludges up. Why not do a little early maintenance

 

If you want to wait that long stuff is nasty crap by 150K and the radiator and heater core are trash.

I hate dexcool it sucks. I just use the old time green antifreeze mixed 50/50 with distilled water and change it every 2 years regardless of mileage.

Drain the system as much as you can fill it up with straight distilled water drive it a few days or an hour or so re drain it follow this procedure 3 or 4 times until it is pretty clear straight distilled water. Then drain again and fill it up with green concentrate antifreeze not that 50/50 pre mix garbage and you are good to go.

Green antifreeze wont hurt a cooling system protects better than dexcool and won't eat up a cooling system like dexcool does. You just need to change it every couple of years. Just like you did years ago when detroit made quality cars that you had to maintain to keep them running. Dexcool was made for the buy it and drive 150K mile people and never open the hood until everything is completely trashed due to negelect crowd. Then go talk to a salesman upfront and start payments all over again.

I dump dexcool as soon as I buy a vehicle then maintain said vehicle and everything works great. My 2011 has had green in it since I bought it. I purchased it up front then drove it around back to the shop dumped the dexcool and put in green didn't even have 2 miles on the odometer.

 

Do not put the green stuff in it. If you dont get all the dexcool out your going to have problems. It will turn to sludge. Theres nothing wrong with dexcool as long as you dont mix green stuff with it. Get 50/50 mix or distilled water and mix 50/50 Dont know if your still under warranty but put green in it and its void as far as any cooling problems go.

 

Nah my warranty is all over so theres nothing to void...i think im just gonna wait till i hit 100k...i work maintaning forklift and lift trucks so i have a water distiller at my disposal...

 

The newer trucks like these seem to do fine with it since they have the pressurized puke tank that does not allow the coolant to be exposed to air. Nothing wrong with letting it go 100K if it still looks pretty n pink.

 

Could also do a PH test with a strip and confirm

 

It looks pretty pink...the level looks a little lower on the dump tank than it was when i first bought it...i did open that tank at least 3 times so idk if thats bad