How quickly will liquids in the coolant system mix

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Hey I need to top off my cooling system. I got some deionized radiator water but I want to keep a certain 50/50 mix. I have a coolant tester that checks what temp the coolant is for.

That said, how quickly will everything mix it to give an accurate measurement when I test it?
 
If you pour the water into the cooling system, not the overflow tank to balance the mixture just run the engine until the thermostat opens, run it for a couple of minutes and shut it off. Go do something useful until it cools and then test it. Don't open a hot cooling system unless you're into pain and don't bother testing the overflow tank, but top off it off to the full mark when you're finished.
 
Originally Posted By: OneEyeJack
If you pour the water into the cooling system, not the overflow tank to balance the mixture just run the engine until the thermostat opens, run it for a couple of minutes and shut it off. Go do something useful until it cools and then test it. Don't open a hot cooling system unless you're into pain and don't bother testing the overflow tank, but top off it off to the full mark when you're finished.



Oh ok. So definitely a car ride where the car gets up to temp will mix everything in?

So what about the about overflow? I looked and I'm low on coolant in the tank and the radiator.
 
Are you wanting to add water and coolant? I am assuming yes since you want to keep it 50/50.

Just get a small container. Dump one of water and dump another of coolant.
 
I would believe one heat up/ cool down cycle should mix things up. That was simple without the "how to mix coolant" advice, which you already know.
 
Once the thermostat opens, you'll be golden in a few minutes if you added it to the radiator. If you're concerned take a 15 minute drive somewhere, at that point it will be very well mixed.
 
Most coolant overflow tanks - at least Toyotas, have a return line to the cooling system. Whatever is added to the overflow ends up mixing in the cooling system pretty quickly if you go through a few engine on off cycles.
 
It's always better to pre-mix coolant and use that to top up, so it's always the same.

if you add water only, a cup or 2 won't matter, but a coolant change must never be
water and antifreeze added separately, localized boiling inside the block can occur,
fluids don't mix well in the engine soon enough to prevent over heating.
 
Most coolant overflow tanks - at least Toyotas, have a return line to the cooling system. Whatever is added to the overflow ends up mixing in the cooling system pretty quickly if you go through a few engine on off cycles.
 
If you want to add just water.. remove a small amount from the radiator.. add it to the overflow tank then add the water to the radiator..

(if you are worried about freezing)
 
You need to specify the vehicle and engine.

Some cooling systems mix the coolant in a matter of seconds. Others will effectively not mix coolant in the reserve tank.

Generally you can tell if the entire system is pressurized, or if the reserve tank is left unpressurized. An unpressurized reserve tank might never exchange coolant with the pressurized part of the system.

The HVAC system is another variable. Some systems use an intentionally leaky heater valve to keep the coolant in the heater core fresh (not depleting the corrosion inhibitors). But that port can easily be clogged, so you can't count on it. This matters when the valve is electrically controlled and the ECU won't open it for you.
 
Huuuh [censored] ok.

To be clear here, there is probably a 50/50 mix now but I can't see any coolant so don't know the colour or condition. Why I just want to fill the rest of it with some water and then when it's full and mixed I will then be able to suck some up in my coolant tester to see the colour condition and the current temp resistance. Anyways the coolant my mom, (old owner), didn't know if she changed the coolant or not. She had the car from new, 2006 Hyundai Tucson

I really just want to have a first idea of the coolant condition so that's why I want everything to be mixed in before testing you know.
 
50/50 either premixed or mixed prior to adding is the only proper way to add fluid. If its low, its low for a reason. Start with topping it off and taking it for a drive/squeeze some lines to get the fluid to mix around in the reservoir to test if how don't want to just drain it anyway.
Best compromise of cost and time is to drain/fill the radiator first and see what comes out. I'd say just open the drain and take a little out to sample, but you might as well just completely drain and fill it.

If she can't remember, than $15-30 worth of coolant is cheap insurance.
 
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