I did mine last fall. 7+ yrs old but only 20,000 miles. Felt kind of silly doing it at such low miles but it's a cheap preventative maintenance item.

 

You can always test your coolant and go from there.

 

21k miles? Gary we gotta get you out and drive a bit more. For a sub $100 maintenance it isn't that bad to do by yourself. I have thought about doing the PH tests. Just to see how 8 years and 70k miles have treated it.
You just don't hear a lot of people talking about doing it. Maybe because you don't do it that often. Or that it is a just a cost of ownership and it doesn't look super cool on the build log.

 

I'm a bag fan of using distilled water for flushing any engine with aluminum cyl heads, more so with block.

 

A test should tell you if you need it or not. But it doesn't mean you can't flush it early. I did mine pretty close to on the recommended schedule. DId it in my drive way with distilled water. There are some great youtube videos on doing.

 

I've never "flushed" mine. But I still do an old-school method a mechanic told me to do back in the green antifreeze days. Every spring, I drain the coolant at the petcock on the radiator and then refill with new (50/50 Dexcool & distilled water).

 

Drain some out and see if it's cloudy or has any gunk in it. If not, pour it back in and keep rockin. I've personally never heard of anyone having serious engine issues due to 'bad coolant' but maybe I live a sheltered life.

 

What can I say? I don't drive a whole lot, especially since all the lockdowns. :roll: I used distilled water, too.

No problems from not flushing? Check out this thread...

Temp operating

 

I had mine flushed last May with 44,239 miles on it. Had the dealer do it while I was in for a free oil change. Cost was $149.
Truck was built in June 2015 so coolant was almost 5 years old.

 

I am in the same boat, and I have gotten the stuff to do it I just have not done it yet.

2009 with 141k never been done.. I have had it since 7k miles

 

Generally I change mine whenever I drain it out, or 5 years. Not even close to hitting the milage so I go by time.

I did mine on my 15 back in March or April of last year. And I did my 01 when I bought it just since it was an unknown.

It's kind of a rip off, but I use the premix. It's just a convenience thing for me, and no messing around getting a 50/50 mix.

 

I am not sure about any other trucks other than the NNBS, but since they dont have a drain and you have to remove the lower hose to drain the radiator, 50/50 won't really work because you can only get about half the coolant out that way. So, basically, you keep draining half and refilling it until it starts coming out clear distilled water. Then drain it one more time and refill with pure 100% coolant to get the 50/50 mix. But since you can only get half the coolant out any one time, you need the pure stuff or you will wind up with only 25% coolant.
I suppose you can use some kind of a flushing machine or something to completely drain it all at once, but I don't know how else to do it in your driveway other than how I described above.

 

Well thats helpful bruce, I was wondering how much would be left it in. I was going to capture what I drained and compare to the amount the manual states.

 

Bradley: I would check this thread out. It is what I used as a guide for my coolant flush.

2009 Silverado 100k Coolant Flush

 

From what I've seen, at least 2014-2018 Sierra and Silverados have a petcock to drain coolant.

 

Wow, GM actually realized how stupid it was to not have one and actually changed it up. Well, good for them.

 

My 13 has a replacement Delco with petcock

 

Well, I don't plan on doing more than one more flush, so I will just deal with the hassle until then. No need for a new radiator just go get the petcock. But, I am still kinda jealous. Wish I had a drain plug on my tranny pan too.

 

Yeah man, not worth the bucks for petcock, needing a new rad, then its a go.

Trans pan, agree, something I will be adding when I do fluid/filter.

 

I was gonna do it on my last pan drop, but I am not all that confident in my welding skills. My son is around now, so maybe next time I will go for putting a drain plug in it. He is a welder and could do it in his sleep.

 

I hear ya, for me I'm just going to get the pan with plug,
I can mig and have one but tig is what's needed here.

It's cheap
https://www.amazon.com/SKP-SK265811-Aut ... erado+1500

I believe Dorman makes one too for around $45

 

Yah, I guess for that price, what the heck.

 

Yepp I said the same, for that price it aint worth messing with, new pan is the way to go.

 

Putting my foot in my mouth here after realizing there's no drain petcock on the 900's, or at least on mine. Really sucks balls to have to use the lower radiator hose.

Anyway, I drained and "flushed" mine with distilled water the other day. I put the truck on an angle to get the block and pump to drain as much as possible and still the most i got out of her was 8 quarts. Manual lists capacity at 17 q. I dunno, 8q residual seems like a lot.

Either way, pink Dexcool is pretty yummy...kind of a watermelon fruit punch flavor.

 

EWWWWW, Yuk. Reminds me of the belly gulp of diesel fuel I accidentally swallowed while siphoning out a fuel mix that my pump jockey messed up.

Mike