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Filling Up Radiator


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just wondering how people monitor/top up the water in their radiators?

on my honda it had a overflow place where you would top the rad water up, without opening the radiator cap...

but on my lexus is200 xreg, it doesn't have a overflow place... should i just add water straight in the rad and fill it up to the top?


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Yep through the cap is the the only way.

Make sure you have the motor running & heater on when you're pouring the water in. A good trick a mechanic friend showed me to get all the air out of the system is to full up a 2L plastic coke bottle with water then put it neck down into the radiator neck. This make a new high point in the cooling system & all the air will rise to it. You may have to full the bottle up a few times. Keep doing this until the radiator fans come on. When they come on it means the thermostat has opened & there's no air trapped behind it that could potentially stop it from opening.

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"Keep the car on and heaters"... ive never heard about this method, i usually top my rads when the car is switched off... never when its on...

do i fill up to the top everytime?

their is two places to check the rad and the overflow you say you cant see(every is200 has one!!!)...............fill the rad to the top and theirs a max mark on the overflow...

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Sorry I didn't read your post properly. The example I gave was for filling a radiator from empty.

As Ormi said there's a header/overflow tank located under the air intake where you can top up from

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stand in front of your car looking down now look at the rad cap...follow the radiator too the left and you'll see a small black cap thats the overflow....

here you go


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