How to Change Radiator Coolent?

Appreciate steps in changing radiator coolent.

For example, do you warm up the engine until thermostat opens up and only then drain? Any bad side if drain and change when the engine is cold?

Reply to
Here&There
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It is very simple. Don't do it while the engine is hot!

1) Open the radiator fill cap.

2) Open the drain c*ck at the bottom of the radiator, put a deep pan to catch the coolant and let it drain.

3) When done draining, close the drain c*ck, fill the radiator with water (don't put the radiator cap on).

4) Start the engine and warm up, until you can feel the upper radiator hose getting warm.

5) Shut engine, drain again.

6) Now fill the radiator with a 50/50 Coolant/Water mix.

7) Start engine, let it warm up. Shut engine, wait a few minutes for air bubbles to escape, top off radiator, sut the radiator cap.

Done!

Reply to
Rajsircar

Does that mean the thermostat need not be open? What about draining when the engine is cold?

Do coolent in the heater get drained regardless thermostat open/closed?

What's the purpose of steps 3--5?

Reply to
Here&There

The thermostat does not need to be open.. It will close shortly after all the coolant drains out anyhow.. The only reason you would want to run it is if you wanted to get some sediment out of the system but changing the coolant when it's hot really sucks and could be hazardous to your skin.

The coolant in the heater will probably halfway drain out, it's not controlled by the thermostat, it is, however, controlled by the heater control valve.

Steps 3-5 is to flush the system of the old coolant. You've drained the system the first time but there's still coolant in it. So you fill it with water and try to dilute the old coolant as much as you can.. You can repeat steps 3-5 as many times as you want until you feel all the old coolant is out but once is usually enough. Also while you're doing steps 3-5 make sure you turn on the heater in your car, that way the heater control valve will bypass coolant into the heater core and flush that out as well.

-Bruce

Reply to
Bruce Chang

I wanted the change when it's cold for the very reasons you brought up, but wasn't sure until now.

So far it all makes easy enough, except step 4 calls for draining when "warm". Doesn't that mean thermostat is open and coolent should be hot rather than warm?

4) Start the engine and warm up, until you can feel the upper radiator hose getting warm.
Reply to
Here&There

That means the thermostat is open and coolant is circulating through the engine block. If the thermostat doesn't open, you won't get a effective flush of the coolant in the block.

-Bruce

Reply to
Bruce Chang

Thanks Bruce and Rajsircar. Now I am raring to go.

Reply to
Here&There

Good advice but it helps to do it on a slope if possible. Aim the front of the car downhill.

Use distilled water only to mix with the AF fill.

Reply to
davefr

remember the heater is your second radiator that can release the dirty stuff back into your new stuff when you turn it on. ONLY a issue if its real dirty when you are changin g the coolent for all quotes there is an equally opposite quote

Reply to
Askari

When you are finished flushing your radiator as you described, won't you be left with an antifreeze mix that is way too low (much less than 50%)? You are only filling the radiator with 50% antifreeze, whereas the rest of the coolant is now water from your flushing. Wouldn't it be better to know the capacity of your entire coolant system, and then add pure antifreeze to the radiator (after flushing the entire system with water) until you're at 50% and then fill off with water?? Or am I missing something?

Greg

Reply to
GBannish

snipped-for-privacy@aol.com (Rajsircar) wrote in news: snipped-for-privacy@mb-m28.aol.com:

This procedure does not apply to all vehicles, especially those with coolant bleeders or those with the thermostat in the lower hose.

Reply to
Death

I was going to post the same comment. In my experience, most radiators seem to be roughly half of the cooling system volume, so I do the drain, water refill, run, then drain again. Then I just put straight antifreeze back in to fill it up. Every vehicle I've had took right around 2 gallons of antifreeze doing it that way and most had a spec in the book of being around 14 to 18 quarts. Using 2 gallons in a 16 quart system gives you 50-50 mix when you are done. If the whole 2 gallons doesn't quite fit I pour the rest into the overflow/recovery tank (which I have flushed and emptied).

-- Elbridge Gerry, of Massachusetts:

"What, sir, is the use of militia? It is to prevent the establishment of a standing army, the bane of liberty. . . Whenever Government means to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise a standing army upon its ruins." -- Debate, U.S. House of Representatives, August 17, 1789

Reply to
AZGuy

a while back I had a old radiator roded out because of stuff blocking it. The guy flushed the system except the heater was off. A hundred miles later I had to do it again because when i turned the heat on, the stuff from the heater blocked the radiator again. Probably just severe cases only. It was really a bad thing though since I was partly accross the state.

Reply to
David Askari

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