draining cooling system how to:

[spongebob]

My engine has 100% water in it and getting ready for winter, Im ready
for draining it and putting in anti-freeze..

as you know there's no drain fitting (stupid move)..how can I make sure all the water is out?

I know I have to pull the lower hose, but what else??

[DmaxMaverick]

Pulling the lower hose fully drains the radiator (easier than accessing the drain petcock, if has one), but the block only drains to the water pump level. To drain the lower block, you'll need to remove the block drain plugs, one one each side. Replacing the block heater will also drain most of the coolant, and near completely on the one side. The drain plugs are at the left/front, forward of the engine mount, and right/rear, behind the starter. It's reported by some that they are painted or marked yellow, but I didn't find any yellow on mine. It's a very early LB7, so they yellow paint may have not yet arrived at the time.

[spongebob]

freeze plugs???

[DmaxMaverick]

Freeze plugs may be more thorough, but I was referring to the threaded drain plugs.

[gbeaird]

Yeah, there are threaded plugs on either side of the block. Removing a freeze plug would work, but would be a TON of work hammering another back in. Not sure why you'd want to drain the block, as long as the water's fairly clean. It'll just mix with the AF you add to the cooling system. Since you're up in the Great White North, I'm sure you're working towards a certain mix, and testing it with a tester to make sure you get it right?

[sctrailrider]

May be a good time to run a cleaner then flush and fill...

[spongebob]

May be a good time to run a cleaner then flush and fill...

I worry about a cleaner, if there's any weak spot in the head gasket it could set it free...

[More Power]

This video has a clip at about the 22:30 point that shows how I drain the coolant. I use a combination of the radiator drain valve on the lower right-rear corner of the radiator and then remove a heater hose that connects to the lower radiator hose. You could skip using the rad's drain valve.



By the way, I believe Dex-Cool coolant is a lifetime coolant (Dex is good for as long as you own the truck). Unless it gets contaminated in some way, drained coolant can be reused. I saw no deterioration in the cooling system when I replaced my 2001 GMC's water pump in 2017, some 17 years since new. The Dex was original. The inside of the water pump looked as good as new. No corrosion, no deposits, coolant was still orange and semi-transparent (still looked like the new stuff).

Havoline, the original maker of Dex, revised their recommendation for service intervals to beyond 250,000 miles. GM's original service interval recommendation was 150,000 miles. There's a sticky forum thread in the Duramax 6600 forum about the long life aspects of Dex-Cool.
https://www.thedieselpageforums.com/...other-coolants

[spongebob]

thanks More power..