[Big Daddy]

When I did mine about 2 years ago, i opened the rad drain plug, took the the rad fill cap off drained everthing from the system, refilled the rad with distilled water ran it for about 20 minutes cranked up the heat. Then done a second drain of the system, I purchased 4 litres of of coolant & premixed myself refilled the system took the vehicle for a test drive 20 minutes cranked up the heat, then home topped off the coolant all good and checked on the level a week later. I also flushed out the coolant reserve I forgot to mention.

 

[Big Daddy]

There is no radiator cap, the radiator is filled from the reservoir. It’s fine to start with 4 qts but I ultimately added more than that. If you fill the reservoir above the “full” line, you will eventually purge the excess when the car is at full operating temps for an extended period. This is assuming you did the fill procedure correctly when performing the service.
I did a write-up when I changed mine.

4th Gen RAV4 Coolant Drain and Fill

Changed the coolant on my 2015 RAV4 today and took a couple pics. This is a simple drain and fill of the radiator, if you want to get all crazy and drain the engine block then the volume of fluid will probably be more. The design of the cooling system on this generation makes it one of the...

www.rav4world.com

You need to go & take a second look there is a radiator cap, I even just checked my 2021 XLE which has a rad cap also.