2019 Prius 1.8L 40k miles.... well maintained by local dealership grey smoke from tail pipe during road trip. 2 days after road trip, "hybrid system malfunction, see dealer" pops up, lots more smoke. under hood, found coolant reservoir empty. refilled, no leaks found. engine accelerates very rough and sounds ugly. coolant low again after drive down street. oil on dip stick looks normal. having it towed to dealership for diagnostic tomorrow am. i am experienced mechanic so it should be something i can fix?
Most likely leaking in the heat exchanger in the exhaust system. We're starting to see more and more of this in gen 4, but I think yours might be a record for lowest miles and newest model. If it overheard, you might also have a warped head which would account for the rough running. Either way, the dealer should be able to chase it down quickly and it should be under the drive train warranty.
Thanks for sharing! I watched videos about it and you're likely right about coolant leak in heat exchanger. Very thankful dealer will handle under warranty.
Forgot to mention, that the hybrid malfunction light went away after I refilled the empty coolant tank. Hoped the problem was gone but engine misfired and shook badly when accelerated. Towed to dealership, bad news and good. More tests needed but verified a much dreaded internal coolant leak. Good news is repairs will be covered under powertrain warranty. Will share update when available.
