My old 2008 Gen 2 had the thermos to hold hot coolant for quicker warm up. Did they do away with it? I don't hear the Gen 4 making the sound.
There is no coolant heat storage tank on the fourth-generation Prius. I assume Toyota’s engineers decided the improved exhaust heat recirculation system (developed jointly with Sango Co., Ltd., and described in SAE Technical Paper 2016-01-0184) and the new active grille shutter system made it unnecessary.
I think the thermos was dropped after the gen 2. My '08 did have one and I always knew the sound the thermos pump made for a few seconds following shutdown. Although lengthy, YouTube has some excellent videos by Weber Auto showing systems and changes from each generation of Prius and one I linked (on the active shutter thread) shows the gen 4 coolant system with the shutters and a detailed look at the exhaust system heat exchanger for faster warmup.
No thermos on 3rd gen. I believe it was the gen that introduced coolant heating through the exhaust, too.
I must have missed that episode that John Kelly does for Weber State in Utah. I will be looking for it today, thanks for the info. I found the YouTube video about the Gen 4 Prius cooling system, excellent video.
Yeah just the Gen 2 had the thermos. The exhaust heat recirculation system took care of the warm-up cycle.
