bad coolant in engine cooling system

There's lots of nooks and crannies where the fluid is hard to clear out. How many locations have you drained it from? Once you identify that we can let you know of the additional places to go after.

 

You're never going to get all the coolant out. That is why Toyota recommends the 1st coolant change at 120k miles, then every 50k miles after.

Do you have pink coolant in the car now? If you do, it probably won't improve anything by you changing it out.

 

Drain* and do the refill procedure with Toyota Super Long Life Coolant. Drive the car a week or two, and repeat. Maybe once more. Each repetition whittles away at the amount of old coolant in the system.

* Really try to drain the best you can. For example, if you disconnect the lowest coolant line on the exhaust heat recovery system you'll likely drain a lot more. FWIW, I've found the engine block drain tap (very hard to access, on back of block) is a waste of time, just drains a few tablespoons.

 

You really can't get it all out unless you pull the engine and tip it over. A lot depends on what is in there now. The best thing may be to repeatedly drain and fill to remove more and more of the old coolant. It can be done with the premixed Toyota coolant but that might be expensive at $25-$30 a gallon each time.

If it is sealer, tap water or an incompatible coolant, you want to flush most of it out. You could buy about 8 gallons of distilled water ($1 each) and just fill and drain it with the distilled water five times. Each time you fill, warm up the engine for coolant mixing and circulation. After five times, drain and add a quart of distilled water and 3.5 qts of Toyota concentrate. At that point you have a very small amount (~0.3 fl oz) of the original in theory. It can be done in a day this way.

 

Always use concentrate coolant; if your system flushing. You won't be able to get the concentration correct if you use 50/50 premix due to dilution.

I checked my GMC truck the other day; I was only around 20% concentration - thanks to my brother doing the antifreeze change a few years ago. Luckily I live in California, where I don't experience many freezes. I dumped about a gallon out and replaced with concentrate to get the proper mixture.

 

Like Toyota Long Life Coolant (without “Super”). There’s a link in my signature with strategy for doing that.

 

Yes. I have done this and just used the radiator draincock.

 

Looks like you got it all... Only thing not mentioned is Inverter and heater circuit... But I'll defer to @Mendel Leisk 's advice on this. He has way more experience.

 

You have coolant be happy is it staying at the level in the jug where it needs to be be happy coolant is coolant is coolant pretty much You're in a car that tries not to get that hot to begin with and cooling is used throughout the systems everywhere The radiator is split up in two pieces to cool all kinds of silliness be happy enjoy your car Don't worry about SLC coolant or whatever you're talking about no matter I have regular coolant and all my Priuses it makes no difference nothing changes Dex cool green cool blue coolant Ship coolant . Nada . Drive on!

 

i'll never forget my first toyota coolant check; pink! i immediately went out and bought some green prestone and replaced it

 

Well if your system holds 7.3 quarts; you'll need about 3.51 quarts of concentrate to achieve a 50/50 mixture. If snow doesn't stick to the ground where you live and drive; I wouldn't worry about it too much.

 

That coolant just didn't seem manly enough for you?

 

Are you ok Tom? Just, I noticed you used a couple of periods and an explanation mark...

Toyota Canada sells SLLC with 55% coolant fwiw.

 

mendel, i had to think about that for a minute, especially since you quoted biomed01

 

If RedPrius moves from Georgia to Canada he will need to add 3.7996071 Liters. Or should I say Litres?

 

Disconnecting a coolant hose from the thermos risks breaking the seal permanently causing a leak from the hose to the thermos bottle. This happens because the hose has been on that pipe so long that when you dislodge the hose pieces of the hose will be stuck to the pipe. I wouldn't do that. Now that those is there leave it there. Just change the fluid and move on