About three weeks ago I had a minor accident at the front of my 2009 TCH. The long story short, the car in in front stopped. I tried to brake, but the Brooklyn Bridge (wet and in construction uneven) made my ABS fail and I hit the other car in front of me. No damage to the other car. The grill (mask) of my car got broken. I opened the hood and noticed both horns and the hood latch were pressed lightly at the converter coolant radiator. No visible leaking. I continued to drive and monitor the coolant level periodically. After a week level went to the low level. I was in the city and had to dive 50 miles to go home. So I bought a gallon of distilled water at the supermarket and filled up the coolant reservoir. During the following days I kept driving and the leaking continued. I was refilling with SLL pink coolant. Yesterday I noticed intensified leak. I bought another gallon of distilled water in the city, refilled and drove home in a way to minimize use of converter (charging/discharging of the battery) and monitor the coolant temperature by hand, coolant level & refill with coolant four times in 50 miles.
All what I was doing WAS VERY RISKY. The damage could have been in thousands of dollars with a fried converter. But I was confident for what I was doing. Forgot, and lucky.
At home, I dismantled the front bumper and noticed three hits (bends at the horizontal flat tubes) at the converter radiator. I blocked two radiator hoses and removed them from the radiator. Blow the coolant from the radiator with air (low pressure) than blocked with my finger the other side. There were two small holes from where air (before coolant) was escaping. I washed them with detergent. Dried it well with hair dryer. Prepared some glue and put it at the three bends). Overnight it dried out like bone.
I refilled the reservoir with SLL pink coolant.
THE MYTH
Even though I do have the means to run the coolant pump with computer I decided to take out the air out of the system (radiator was empty) by turning the engine ON. Simple, being lazy. My battery was full so the engine was running to bring the ICE temperature up. Even though charging does not create much heat to the converter, driving through MG2 DOES create most of the heat. All Air came out and I refilled it couple of times. Job done. I will keep monitoring this periodically as I have done since I bought it new. I plan to replace all coolant soon after proof that I do not need new radiator.
Conclusion: For those that do not have a Toyota scanner or an aftermarket, replacing the hybrid coolant is not a problem, especially if you start this process with a fully charged battery.
I repeat again: All what I was doing WAS VERY RISKY.

 

Well,

I certainly agree with one thing, what you were doing is extremely risky. It's like playing Russian roulette where you have a 1 in 6 chance of it going "bang" and ruining your day.....

 

Everything is working perfect. I am planing SLL coolant replacement soon. By the way with this weather I am getting 39.+MPG with this tank.

 

Changing the converter coolant heat exchanger isn't that difficult. My kid mauled the front end of the car, and about a year later the dented passage in the exchanger started leaking. I took it to the dealership, and they diagnosed the leak and wanted $400.00 to change it. This is suspiciously low for a stealership job, so I investigated further.

The exchanger is $219.00 at the dealership and the pink coolant is $30.00 a gallon. The exchanger could be found online for about $150.00, but I was pressed for time, and bit the bullet at the stealership. It took my son and I less than an hour to replace it. The most difficult part was that I needed his smaller hands to get to a couple of bolts on the sides. It was pretty easy job, just a few wrenches and a probe to separate the hoses from the metal of the exchanger. It comes out from the top, straight up. You need to remove a few bolts to get the crossmember above it loose, and there are 2 bolts on each side that require a socket with extensions, but it isn't a major job.

A rating system that is used to measure difficulty of mechanical jobs in 'banana' units, would put this on a scale of 2 out of 10 bananas. One banana being an oil change and ten being a transmission/engine overhaul. This one is surprisingly easy.

Just my 2 cents.