i've always just drained the block (2) and radiator (1) petcocks and refilled with no problems on any of my cars. i think you'd need to have a flush done where they have a way to hook up the hoses to a machine to dispose of the old fluid, etc. though.
tony

 

So you drain out the coolant that is in the engine block and refill the radiator, is the pump running dry until the thermostat heats up and is opened and fluid circulates? Or how is the engine getting fluid in it before you start the car?

 

Here's what I've done with both my Camrys.

Drain radiator through bottom petcock drain and refill with distilled water. with petcock closed. Leave radiator cap off and run engine till it reaches normal operating temperature with the heater on full blast inside the car. Drain radiator again (careful not to burn yourself) refill with distilled water.

Repeat the above steps until fluid coming out of radiator is clean. Always use distilled water.

The last time you drain the radiator, refill it with full strength Toyota red antifreeze. In the over flow reservoir add half antifreeze and half distilled water. Run engine with radiator cap off and add mixture to radiator as needed to completely fill it as it will burp letting any air out. Replace radiator cap.

Keep a watch on the overflow reservoir over the next few days and add 50/50 mixture if needed.

This sounds like a lot of work but it's not that bad. Good luck.

 

I open the radiator petcock all the way, put the garden hose in the filler, and regulate the flow so it just dribbles over the top of the radiator. Then I start the engine and let it run for 15-20 minutes. When the water coming out of the petcock is hot and clear, shut off the water, shut off the engine, wait a while until the radiator is empty, tighten the petcock and fill with full strength genuine Toyota coolant (nothing else has the exact same chemical formulation)

 

So I just followed the instructions on the back of the jug. Drain, re-fill with distilled water, heat up, and drain and repeat until the fluid comes out clear.

It took almost 8 gallons of water to flush out. Playing with my antifreeze tester, looks like last time it was filled without being deluded very much. Or maybe not any at all. A bit of corrosion on the bottom of the radiator cap and blue specks stuck to the side of the reservoir tells me that a coolant flush was a bit overdue.

Does it usually take that much water to flush it out clear?

 

In my Camry 2000, there was pink coolant in my radiator. I had to drain a radiator a little to replace one of the switch. I didn't have Pink coolant but had Green Anti-Freeze Coolant, I mixed little water with green coolant and topped it off ( about half a gallon), that means I mixed green coolant with pink coolant. Is this a big problem?