When I drain out the radiator's water , how can I properly refill it , so no air will be "trapped" inside?

Question

The " trapped" air will cause the engine to overheat.

Answer 1

The fact that people are so flagrant about their small amount of knowledge of cooling systems amazes me.
I've seen more than enough engines overheat due to cooling cavitation. It isn't a very serious issue, true, but of course it happens. Anyone who says it isn't true has never heard of a reverse cooling system, in which it is necessary to bleed the air from small screws in spots along the system to prevent air cavitation.
That said, where I work, our normal process for cooling system filling entails filling the system, and then running it until the thermostat opens. When this happens, most of the air is released and you'll notice the coolant level drop about 1/4 gallon in the fill cap depending on the type of car. The system can then be filled and driven. However, it is true that problems can still happen; a lot of cars are built differently and have their own quirks, but this works 95% of the time.
And no, we don't charge people more to do this. Its better to do it than have someone's car overheat three days later because you thought it was "just an old wive's tale".

Answer 2

Fill it back slowly, let the bubbles gurgle out, then top it off. Repeat until it stops gurggling. Give it some time to settle. Then run it for a bit, let it cool, then refill. You may have to recheck it after a couple of days.
you'll always have alittle air until you actully run the engine, but that wont hurt anything. Once the pump is going and it builds pressure most of the air is out. Just make sure you let it cool all the way down before the next step. AND keep an eye on your resivor tank.

Answer 3

Having to go through complex procedures to "burp" trapped air out of cooling systems is just a scam crooked mechanics use to part you from your money. Any air will work it's way to the radiator, so you just top it off a few times after you've test driven it far enough to get it hot enough to get the coolant circulating.
If you keep the overflow reservoir full, the radiator will blow out any remaining air when the system heats up and suck up water when it cools down.

Answer 4

air will find the highest point in any closed system , sometimes it is the heater so an " old wife " will be cold . with the car running , cold , and the rad. cap off , fill the rad. , rev the engine up and the level will drop , put more in at this time , a helper is nice at this point , put the cap on ,let the rev's drop and fill the overflow tank to the cold mark , keep topping it off over the next week or so . good luck , be safe.

Answer 5

THere is no proper way to fill a radiator.You just fill it up,any air in the system will work itself out while you drive.There is no trapped air,thats an old wives tale.