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Tricks to doing a coolant flush? (2007)

16K views 5 replies 5 participants last post by  Meves 
#1 ·
Hello,

New here; taking over maintenance on my parents' 2007 Equinox. Now 99k, they have had it since new. It was my mom's company vehicle so had fleet maintenance done by the book for the 1st several years/60k or so but nothing the last few years since they bought it other than engine oil. Among other things, I was wanting to do a flush on the coolant, not just a radiator drain. I searched the best I could and I found this helpful post:

http://www.equinoxforum.net/index.php?topic=4435.msg58894#msg58894

But it only covers a radiator drain and I am wondering if there are block drains so I can get more out at once? I was hoping to drain the block as well as radiator, refill with dH20, run to open heater core, drain again then refill w/Dexcool. Will that reservoir fill procedure work for me if I am able to do that?

Also I am looking to exchange the ATF via the cooler lines. Have done this before on other vehicles - any tricks here (I am aware of using T-IV compatible fluid)? Or if there is a DIY somewhere; I searched but did not find one. Thanks in advance!
 
#2 ·
Several highly regarded mechanics have told be to get the Dexcool out and only use a high quality green coolant.
I've had heater cores partially plug up with Dexcool and supposedly that won't happen, or won't happen as soon with regular green coolant.

Just my 2¢
 
#3 ·
Dexcool of the 90's had lots of problems, and has had a bad rap since then. If you maintain the vehicle and stick to the service schedule, Dexcool isn't a problem. The reason Dexcool exists (along with the likes of HOAT, Ford Gold, Honda...) is because the old fashion green coolant doesn't last nearly as long. Dexcool is good with 5 years or 150K miles, green stuff is good with 3 years 36K miles. I don't care what the jug says on it, if it's green stuff it's the old formula and isn't going to last as long.

With that said, I had hard time getting Dexcool in my area a few years back. I flushed my old car out and went with the Green stuff because I could buy that at any gas station (if needed). I also just accepted that I would be flushing ever 2 years. However these days, I could get Dexcool at Walmart.

It sounds like you are pretty confident in the actual flush, but I can't say if there are any block drains. You do get most of it when you drain the radiator.
What I have done in the to get around that is to just flush the block out with tap water ( I've also done the chemical flush) with the lower hose disconnected. Once it's all running nice and clear, I poured through about 2 gallons of distilled water to displace the tap water. Getting to the 50/50 ratio isn't easy or cheap. This depends on your total capacity, but I did the same thing with coolant that I did with the distilled water. I poured in 50/50 until the color of what is running out of the engine looks good. That's why I say there isn't that much in the block as on my old 3800, that only took 1/2 a gallon. I also drained and filled my heater cores separately so that there isn't a hidden pocket of water there, but they were easy to get to.
 
#4 ·
To address ORO's question, I would suggest draining the radiator (engine cold), the refill with tap water, run for a minute or two (heater on). then drain.
Refill with tap water and run and drain again. If the drain water is pretty clear, add new coolant per manual and fill with distilled water to top of radiator. If drain is still not clear, repeat fill and drain. The overflow/expansion tank may have to be removed to empty and clean depending on easy of doing so. A siphon can get most of that coolant out.
 
#5 ·
Example---


On my 2003 Trailblazer----
50,000- partial fluid was removed/refilled.
111,000 - I replaced thermostat- fluid partial drain/refill
133,000 - upper/lower hoses replaced- coolant drained/refilled.
173,000 - coolant drained/refilled. (1 week ago)


If your parents vehicle was maintained- and dexcool changed based on mileage/time...
it will be fine- and you should not have a need to flush it.
Everytime Ive drained coolant on my Trailblazer- it looks brand new.... Nice clear and pink/red.
No corrosion, no globs, nothing...
what comes out-- looks like whats going in. (except the older stuff is 'depleted')
I simply drain and refill.
In fact I just buy PRESTONE- PREMIXED 50/50 DEXCOOL (GM aproved). and refill- I dont mess with premixing the concentrate with water. its just easier.


So if you drain yours-- and it comes out clear and pink... I would just refill.

I would flush when the coolant comes out rusty looking like older cars.


This is an image of the inside of the Trailblazers coolant passages @ 111,000
You can still see the small circle patterns of the lost foam casting method.
Super clean inside those passages.

 
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