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When to change antifreeze?

2013avalanche

Full Member
Joined
Mar 2, 2014
Messages
138
Have only 25,000 miles on my 2013 avalanche, coolant looks good, not much towing, gentle use. Is it ok to go 100,000 miles at this pace without changing coolant?
 
Copied from my manual:

Engine Coolant
The cooling system in your vehicle is filled with
DEX-COOL? engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add
only DEX-COOL? extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, see Engine Overheating on
page 5-26.
A 50/50 mixture of clean, drinkable water and
DEX-COOL? coolant will:
? Give freezing protection down to -34?F (-37?C).
? Give boiling protection up to 265?F (129?C).
? Protect against rust and corrosion.
? Help keep the proper engine temperature.
? Let the warning lights and gages work as they
should.
Notice: Using coolant other than DEX-COOL? may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs first. Any repairs
would not be covered by your warranty. Always use
DEX-COOL?(silicate-free) coolant in your vehicle.

Check your manual for information about your model year.
 
2013avalanche said:
Have only 25,000 miles on my 2013 avalanche, coolant looks good, not much towing, gentle use. Is it ok to go 100,000 miles at this pace without changing coolant?
You can't tell if coolant is good by looking at it. Follow the owner's manual requirements of 5 years. Changing the coolant is relatively cheap and will absolutely prevent future issues like electrolysis and internal corrosion due to depleted coolant additives.
 
I would only use distilled or purified water when refilling. Or only buy premixes 50/50. The "Drinking water" mention is not correct. If you use normal drinking water it generally has minerals in it that can coat your radiator by design as they are intended to coat the pipes (See Flint Mi for what happens when they DON'T put this stuff in their water).

I try to use ultra pure water and distilled if I can't find ultra pure water.

At best if you use drinking water you will use up some of the protective chemicals in the coolant to counteract the stuff in the water.

When I do mine I grab about 10 gallons of ultra pure water from work, flush out the old coolant by draining the radiator, refilling with water, run the truck until it reaches operating temperature for 5 minutes to know the thermostat is opening, shut it off, let it cool, drain out the coolant and repeat until I get just water out. When I get to that point I then drain out the radiator and top off with full strength coolant, run until it gets to operating temps, wait 5 minutes to allow full mixing then test the coolant for how cold it is good to.

You MAY be able to short circuit the process by removing the thermostat and leaving the radiator plug partially open and just topping off the level with water until you get clear water out of the drain then shut the truck off, remove the thermostat housing and open up the drain the rest of the way. Keep track of how much coolant you have to add to the system. When you pull the housing you should get out more coolant. The radiator doesn't hold quite half of the coolant on its own so you can end up wasting a little coolant if you use the method I first mentioned.

Also note that the coolant is toxic to animals and should be captured and disposed of properly. Dumping down a storm drain is illegal in most states if not all as it normally goes directly to a water source.
 
Dexcool recommends using drinkable water as well. I have always used tap water, maintaining coolant at the recommended intervals (Dexcool was every 3 years when it first came out), and have never had a coolant-related issue. I believe the risk is pretty small if using municipal water; extremely hard well water could certainly cause issues. The well water at my property has so much lime in it that it is very difficult to keep plumbing fixtures clean.
 
I just buy the 50/50 and be done with it.

I got no time for that measuring and mixing crap.

My time is worth more than the cost difference.

They should be able to measure better than I would care to do, anyways.

If you do need distilled water, most grocery stores have it in the bottled water section and it's cheap.

Whatever works for you.
 
EXT4ME said:
I just buy the 50/50 and be done with it.

I got no time for that measuring and mixing crap.

My time is worth more than the cost difference.

They should be able to measure better than I would care to do, anyways.

If you do need distilled water, most grocery stores have it in the bottled water section and it's cheap.

Whatever works for you.

How do you empty the 100% water out of the block before adding the 50/50 mix? Assuming you completely flush the old coolant out first until nothing but clear water is coming out. The block holds approximately 50% of the coolant capacity so you will only have a 25% coolant mix. That's why I use straight antifreeze - when I fill the system and it circulates I end up with a 50/50 mix.
 
MyBigToy said:
How do you empty the 100% water out of the block before adding the 50/59 mix? Assuming you completely flush the old coolant out first until nothing but clear water is coming out. The block holds approximately 50% of the coolant capacity so you will only have a 25% coolant mix. That's why I use straight antifreeze - when I fill the system and it circulates I end up with a 50/50 mix.

I don't flush.

Some may not agree, but this has worked fine for me.

There never is a chance to get 100% water in my block.

Whatever coolant is in there is the same 50/50 that is in the radiator and hoses and whatnot.

It seldom gets below freezing here, maybe once or twice every couple of years and my truck is garaged.

The coolant tester always show I have full range of coolant protection.

The system cools fine, as well.

The only time I have had to add any coolant was when I changed out the radiator and/or thermostat.

Then, whatever comes out gets replaced.

I change hoses and thermostat at the same time I change out a radiator, which I have done twice on this truck with one time I found out later was not needed.

Pin hole in a hose I didn't find until I was well into the repair was the problem.

My bad, but I do have a new radiator, so I guess that's something.

So, I have very seldom had reason to refill the coolant.

Two big refills over the past 100K miles I have owned the truck should be fine.

I've never seen anything from the parts that come out that indicated I needed to do a flush.

If I did, I would flush.

At 225K miles and no gunk or signs of corrosion indicated, I feel confident that I will be OK without doing so.

Any remaining coolant in the system is going to be 50/50.

Once the repairs are done, I refill the system with 50/50 like is what is already in the system.

So, 50/50 comes out, then 50/50 goes back in.

The only cooling related issues I have ever had with this truck, other than that sneaky pin hole in the hose, were directly related to a worn out clutch fan.

Replaced the fan clutch and the problems went away.

But, what I know?

???
 
I prefer to flush the block, but it is a lot more work that way.
The quick and dirty way is to put the correct amount of pure coolant into the system, and top off with water until it's full.
But if you want to get all the water out of the block, take the block drains out.
My old GMC truck had them, and I imagine Chevy motors still do.
Anyway, a lot of crappy rusty poop came out of there when I took the block drains out and blasted it with running water until it was clear.
Then once all the water drains out, simply refill the system with premix and you're good.
I did it the first way on my Avy last time around.
I think I will remove the block drains next time, just to see if it runs clean...and then I'll have an idea of how well maintained it was by the former owner.
My 2?.

CarMech1969
 
When using Tap water you need to check to make sure your locality does not use phosphates in their water. If they do it will eventually coat the coolant lines in your vehicle to the point it will be very difficult to get it out. Again limestone and some other minerals can greatly reduce the protective components of the coolant. Things you can't know for sure unless you have the water tested. I can assure you that if your water does have phosphates in it, as most municipalities do, you will coat your coolant system with chemicals and minerals that will degrade your system over time. I am in the water treatment business and have held state licenses for almost 30 years.

I know I have had vehicles that have shown signs of coolant issues from our city water. I have also had issues with heater cores plugging up then basically coming apart using city water... So again. I strongly suggest against using it.. Just because you haven't recognized any issues yet doesn't mean it isn't causing corrosion or other issues within your coolant system somewhere.

Rodney
 
All good points.

But 50/50 insures no city water in my system.

Solves that problem for me.

(y)

 
We have 3 different approaches. Rod's is likely the safest approach, followed by mine, then EXT'S (due to leaving older, at a minimum somewhat depleted coolant mixed with new coolant).

I owned my Avalanche for 14 years and never had an issue with cooling by following the coolant manufacturer's recommendations.  I have been servicing my coolant like this for over 40 years now with never an issue, so the track record of success is fairly good.

I guess it boils down to picking your poison and living with the potential consequences. I do know one thing for certain - any of these methods is better than not servicing the coolant system based on the coolant manufacturer's and GM's recommendations.

 
I wonder what the whipper snappers do these days.

(y)
 
Most shops use tap water but then they also power flush the system and they enjoy your return business when you have to get it power flushed again.

Using 50/50 mix does work if you drain out the system fully. Then again if you dump the radiator every year or two and top it off with fresh long lasting 50/50 then you probably never will have an issue. (Long lasting as in 100,000 / 10 year coolant.)  That $6 or whatever it is now for a gallon is pretty cheap.

When we used the green stuff and flushed the system out every year or two it make a much higher impact. But again will depend on where you are located and what they add to your water. If you used tap water from flint a year or so ago it would likely have caused issues for any vehicle. But then again, corrosive water would have likely cleaned out the block... ;)


Rodney
 
With all the policies/laws about hazardous waste disposal and the cost or time involved to get rid of old radiator fluid and oil etc. I'm kind of surprised there is still a percentage of people being "shade tree mechanics" anymore. Combining that with homeowners associations wanting to keep neighborhoods in perfect shape with no unsightly or noisy activity. Then the complexity of newer vehicles with all the sensors and black boxes making it hard to work on vehicles on your own.
I know some things about the past were hard on the environment but it sure was easier when you could just let your radiator fluid run down your driveway and just hose it off into the gutter. The old oil was poured in sidewalk/driveway cracks or anywhere you didn't want grass to grow...Surprised we survived our childhood at times... >:D
 
Depending on where you live, some of those practices still exist.

A lot of places, I bet.

Our local government closed our only recycle center a year ago.

When publicly asked what we should now do with our paper and plastic waste, we were told to just toss it in the trash bins.

It still goes to the same landfill dump as it always had.

Now, they are just not going to pay a guy to stand around by the recycle dumpsters all day.

:E:

To their credit, they do hold a spring cleaning event where you can bring oil, paint and other waste in to a collection point at the local high school.

Now, where all that stuff ends up is anyone's guess.

At least it is out of my garage.
 
I am in the transmission pan drop and filter change camp, as well.

:laugh:

 
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