1997 4Runner cooling system flushing tricks

[Ski Krazy]

Need the proceedure to flush the entire cooling system of a 1997 4Runner V6. The red Toyota coolant got mixed with 2 quarts of green.

[Brian R.]

I would drain the old coolant from the radiator, block, and reservoir, fill the radiator with water when the engine is cold and let the engine idle with the inside heaters on, front and rear. When the thermostat opens, keep the level of water in the radiator filled to the top. Once the engine is hot, shut it off and let the engine cool down a bit and then drain the water from the system - block and radiator. Don't bother putting water in the reservoir. If you're really anal, you can repeat this procedure as many times as you want. Just make sure you are filling a warm or cold engine with water, not a hot engine. A hot engine can boil water and cause you a lot of pain. Might damage the engine too.

Fill with coolant the same way, cap the radiator after the engine is hot and no more coolant can be added to the system - heaters on, and make sure the reservoir is at the full mark with coolant. After the water flush, to be safe, I would add 60% antifreeze/water to the system in case there is some water left in the engine block after your done draining the engine.

Another way is to buy a radiator flush and follow the directions.

[4Wheel]

Without "pressure" flushing (as Brian said) the only way to completely drain is to remove the brass drain plugs on both sides of the side of the engine, a little hard to get to. Then you may have trouble with air in the heater core so it might need to be "burped", generally not though.