Updates: P261B just came up but still drives

ok here it the update: So now I'm 100% sure I had a cracked or blown head gasket. For the past 1 month, I still had to drive this car so here is what I did. I completely loosen the coolant reservoir cap and have 1 gal of double filtered water in my car to fill up the coolant whenever I drive. Since I loosen the cap, there is no pressure in coolant system so not much coolant could go into the combustion chamber so engine didn't knock much maybe just a lil shakes at stop-n-go. Freeway no shakes at all. During this time, I also did some more research on the Bar's leak. Its possible to clog your radiator so as long as the thermostat doesn't open, it won't go to the radiator. I have been monitoring the temperature for a while. The coolant temp usually don't go up to 171 F (the thermostat open at 171 F) if you turn the heat to MAX and the fan to half way or MAX. The coolant temp stays around 155 F. So the coolant just circulating between the reservoir, engine block and the heater core. Ya I know it may clog your heater core too as some reported but you maybe able to flush it with hose water.

So after all these thoughts, I finally tried the Bar's leak. I pour half bottle into another water jar and mix it with some double filtered water and shake it up very good before I pour it into the reservoir. so NOW I tighten the reservoir cap because it needs pressure to push those little pieces of carbon fiber to the cracks so they can fill it up those cracks. I followed the instruction and put the Prius in maintenance mode so the engine keep running and heat & fan to the MAX for 15 to 20min. I did 19min. There was a lot of white smokes but engine didn't knock too much maybe a lil bit when started. After that 19min, I let the car cool for 30 to 45min. And then drive around the block slowly for 15 to 20min as instructed. There was still some white smoke looks maybe just a lil bit less than 40min ago. At night, I drove again for about 1.5 hours some up hill and down hill too. To be honest, there was a time the temp reached 188 F so some may have gone into the radiator. So day 1 finished but still some white smoke. Day 2 still a lil bit smoke but much thinner. Day 3, there is really NO white smoke at all. I mean NO AT ALL. The reservoir cap has been tighten at all times but there was no knocking and shaking at all. I paid a lot of attention during those stop-n-go, there is no shaking at all now.

In conclusion, I considered this Bar's leak is success for me so far. I don't know how long it will last but I hear some reported 3 years still running no white smoke. My Prius has 250K miles. I hope I can drive it to half million. Lets see!!

 

I know what you mean. I may just do a coolant flush and get all these pieces carbon fibers out.. Oh well, as much as I can. I think the cracks have been sealed by now. I don't need them in the system now.