Mixing Coolants

[polarzak]

MY 06 GM came with Dexcool (orange stuff) in the rad, and now I would like to drain as much of it out as possible and refill. Obviously I am not going to get all of it out. I bought Prestone (green) that says it can be mixed with ANY other antifreeze. Anybody out there mixed Dexcool with the Prestone that supposedly mixes with all antifreeze? Thanks.

[aleekat]

Yes.

[polarzak]

Originally Posted by aleekat

Yes.

Thanks for the lengthy and informative reply.

[aleekat]

Answered what you ask. Drained out my Dexcool. Added walmart green stuff that mixes with everything. No issues.

[polarzak]

Thank you. That was what i needed to know. (no issues)

[Blue Bowtie]

Check again soon and frequently for solids precipitation (sediment formation) in your cooling system from mixing silicate-free coolant and old-school antifreeze.

[polarzak]

Originally Posted by Blue Bowtie

Check again soon and frequently for solids precipitation (sediment formation) in your cooling system from mixing silicate-free coolant and old-school antifreeze.

Yes...a valid point. I went on the Prestone site and they say their premixed Long Life version is silicate free, however make no mention that their Long Life concentrate - which I bought - doesn't have it. I treat this vehicle better than my wife (or so she says) so I think I will just go buy some Prestone DexCool, and take the Prestone Long Life back.
Thanks for all the replies.

[MagicRat]

Originally Posted by polarzak

. Obviously I am not going to get all of it out..

Yes you can. Disconnect the heater hoses and the upper radiator hose.
Hook up a garden hose to one heater hose outlet and turn on the water. You will fill the block with water. Eventually water should come out of the other hose outlet and the upper radiator outlet. Let the hose run until the water coming out is completely clean and clear.
Then flush the heater core with clean water in the reverse direction of the coolant flow. Be sure to disconnect any coolant shut-off valves.

Then disconnect the lower radiator hose, or the radiator drain valve and let all the water drain, then hook up all the hoses. There will be some fresh water in the block, so you should add 2 or 3 liters of concentrated anti-freeze to the system first, then top the rest off with pre-mix antifreeze.
I think you are safest adding 60/40 antifreeze/water mix.

[polarzak]

Originally Posted by MagicRat

Yes you can. Disconnect the heater hoses and the upper radiator hose.
.

Thanks for the information; seems simple enough to do, however why disconnect the upper rad hose? Won't the thermostat be closed anyway?
Thanks.

[Blue Bowtie]

It can be flushed completely. Just make sure that happens if you decide to change to the older coolant. There's nothing wrong with the older coolant if you maintain it (change every 36 months).

[Tech II]

I don't believe in mixing, just complete flushing.....flush the core......remove the lower rad hose from the radiator and flush the radiator.......remove thermostat housing and thermostat, remove the block plugs, and flush through the thermostat opening.....

[polarzak]

Thanks everyone for the info. Seems like I must have lived right last week, as the local garage had a sale on flushing and refill...Only $30 more than for me to buy the coolant and do it myself. I took my jugs back for a refund, and then watched as they flushed it, and refilled with DexCool. The more I read about Dexcool, the more I concluded that in my engine, it is not an issue to use it.