Alright, the guy at the dealership tells me one way to do this through the heater hoses heading to the firewall...the others tell me to pull the drain plug, drain it, fill the radiator with water, run it then drain it again...what about the surge tank? I need a step by step on how to do OUR vortec 4.8l V8's, not a general vehicle flush, how do i do this? 22K miles and my coolants almost brown with foam on the top

 

You probably already know this, but that brown crap is not good; maybe your coolant has become contaminated. Have you (or anyone else) added water or coolant to the system at some point?

The reason I ask is that the Dexcool in our trucks can become really evil if you mix the Dexcool with another type of coolant or if you add regular tap water. Hopefully, that's not what's happening with yours though!

 

The only thing is it sat on a dealership lot for one year, and driven to texas twice before that fully loaded with the previous owner without an oil change (about 7K mi) before he changed it, then he added water wetter to it before he traded it in when i bought it...so it hasnt been babied, theres brown foam on the top of the coolant and the tanks full of like discolored orange, i know its supposed to be bright orange so im a lil nervous thats why i want to flush this thing asap! I bought 2gals of Havoline 50/50 dex-cool approved coolant today, says its for gm trucks...thats the right stuff right, i dont need full strength dexcool right?

 

That's right, I use the 50/50 premixed stuff with no problem.

 

When doing the flush you want to drain the system and fush it out with water in a reverse flow, this will wash out the larger crap that gets stuck on the inlet side of the heater core and radiator. Disconect both heater hoses and flush the heater core seperate this will help to keep the sediment out of the cooling passages in the engine block, be carefull not to use too much pressure or you will mess up your heater core. I would pull the radiator and flush it seperate also this will give you good access to clean the cooling fins out at the same time. Now that you have all of your hoses off run clean water into the heater hose nipple off the engine to flush the block.
After you have flushed the system re-install all hoses with new clamps (not mandatory but good insurance) and fill the system with a 50/50 mix of antifreeze of your choice and distilled water. Antifreeze alone has poor cooling properties, it's only purpose is to increase the boiling point and freezing point of water. Using distilled water will reduce the depossits that form over time in your cooling system.

 

I agree with all of the above. The only two additional things I would do are pull the water pump to flush it separately and gain access directly to the engine water ports, and also get a wet/dry vac to suck as much of the hose or tap water out of the system as you can before you start refilling everything.

 

Pk so disconnect the two coming off the firewall and spray into those with water...pushing all of it out where?

 

One is the inlet and one is the outlet. Spray into one and everything will come out the other one.

 

witch one is the inlet

 

Yeah im guessing the one out of the firewall end is the inlet and the waterpump end is the outlet? this si so confusing i want a step by step from someone who does these trucks all the time...surge tank water pump radiator, so much to flush i need steps 1-?