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How Did You Flush Your Coolant?

tweba99

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tweba99 Enthusiast

tweba99

Posted
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I am going to go ahead and flush my coolant this weekend since I am over 100K now and I wanted to see how everybody flushed theirs with the 6.0. I usually drain it and pull the lower hose from the radiator to drain the block also and then cycle it through with water, super flush, and the heater on high for about 5 minutes and then turn it off and flush the water out and fill it back up with antifreeze if it comes out clear and if not, I repeat until it does. I know this way is the messy way but it usually gets everything flushed out. Any suggestions on my method or ways you have done it to make it easier?

takethebounce Enthusiast

takethebounce

Posted
Posted

Last time I did it, I picked up one of those backflush hose adapter kits, it was about $5. I cut a piece of extra hose I had and attached it to the adapter, then pulled off my heater hose and attached the extra section to the heater out side and the adapter to the hose. I didn't want to leave the backflush kit on the truck, thats why I cut the extra hose.

 

There is a drain plug and I would assume one on yours. Lower left (drivers) side of the rad. Just a 1/4 turn and it should open up. Saves on pulling the lower hose off.

 

With the backflush adapter I hooked up a garden hose and flushed out all the old coolant. I removed the garden hose and added the super flush. Some people say its bad for aluminum parts but its only in there for a few minutes. I ran the engine as you did for 10-15 mins then drained it. I hooked up the garden hose and pulled off the rad cap then flushed it out until the water was clear. Drained the system again, put the heater hose back on as it was and then started to top off my system with the Dexcool.

Freyguy Enthusiast

Freyguy

Posted
Posted

I researched a good bit, and found this method was widely used.

 

I ran it hot so the thermostat would open. Then I would drain the radiator from the tube at the bottom and it also drains the tank. Then refill with distilled water. Run again for 5 mins at a decent rpms. Drain, fill again, then repeat. I did this until what came out was pretty clear. I think I bought 12 gal of distilled water and went through almost all of them. On the last drain, just fill back up with straight antifreeze/Dexcool to get close to a 50/50 mix.

tweba99 Enthusiast

tweba99

Posted
  • Author
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I researched a good bit, and found this method was widely used.

 

I ran it hot so the thermostat would open. Then I would drain the radiator from the tube at the bottom and it also drains the tank. Then refill with distilled water. Run again for 5 mins at a decent rpms. Drain, fill again, then repeat. I did this until what came out was pretty clear. I think I bought 12 gal of distilled water and went through almost all of them. On the last drain, just fill back up with straight antifreeze/Dexcool to get close to a 50/50 mix.

 

This is pretty much the same method that I use. I "think" that i have a coupon for a free coolant flush so if I can find that, I will let them do it and MAKE SURE they put dexcool back in. If not, I will just do it myself and make a little bit of a mess again in my driveway. :)

masterp2 Enthusiast

masterp2

Posted
Posted

A good DIY flush involves removing the thermostat(s). If you use a flush agent, this will be most effective.

 

If you don't, the radiator will see very little/no flush action.

  • 3 weeks later...
1999 Tahoe 4x4 Enthusiast

1999 Tahoe 4x4

Posted
Posted
I researched a good bit, and found this method was widely used.

 

I ran it hot so the thermostat would open. Then I would drain the radiator from the tube at the bottom and it also drains the tank. Then refill with distilled water. Run again for 5 mins at a decent rpms. Drain, fill again, then repeat. I did this until what came out was pretty clear. I think I bought 12 gal of distilled water and went through almost all of them. On the last drain, just fill back up with straight antifreeze/Dexcool to get close to a 50/50 mix.

 

This is pretty much the same method that I use. I "think" that i have a coupon for a free coolant flush so if I can find that, I will let them do it and MAKE SURE they put dexcool back in. If not, I will just do it myself and make a little bit of a mess again in my driveway. :cheers:

 

Hot engine and cold water? I would be too worried to crack the cyle heads. Do it with a cold engine and remove the thermostat, then you won't have to worry. Plus this way you can replace the $15.- thermostat too. It is a relatively inexpensive item, that can cause major head ache if it goes.

 

This is how I did it on my 5.7 / 1500. Please note that the fluid capacities might be different on your rig.

 

I removed the thermostat and put the housing back on, opened the upper radiator/hose connection at the radiator. Extended this radiator hose with an adapter and some clamps so, that it leads out of the engine compartment into a bucket. Then with the engine cold and running I started to pour water into the radiator throught the filler neck. It took long about 5 minutes/50 gallons after finally undiluted clear water came out of the engine through the hose that lead into the bucket.

With the engine running I stopped adding water filling the radiator, and cosequently within seconds water stopped coming out of the hose. NOW ACT VERY QUICKLY (don't let the engine run this way too long). I left the hose connection open and filled in8 liters of coolant with the engine running while observing the open hose side where still only fresh water appeared. I stopped the engine and I closed off the system, I topped it off with appox 2-3 liters of 50/50 antifreeze and aired it out at the same time.

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