Greetings PRIUSchat, I have a 2011 Prius with ~180k miles on it and have been experiencing engine knocking all year. My coolant level drops and I have pressure tested it many times and there appear to be no leaks. I'm worried about the head gasket . . . or should I be worried about the EGR valve being an issue? Can you guys suggest the best way to try and attack this 3rd gen engine knocking issue? Other than the occasional knocking, the car runs great, but the knocking is starting to become much more frequent at start up/recharge. Cleared the check engine light a few times but it comes back on after some time, few codes that show misfire in a few cylinders. Thank you all & God Bless
Your fear of the head gasket has just shown it's true form. You'll need to replace the head gasket or get yourself another engine. No other real solution
Did you use a bore scope to see the coolant leaking into the cylinders? It doesn't take a lot for the engine to knock..... Sounds like the head gasket is leaking... it will only get worst. The longer you wait the more it will likely cost you....
Update: I added K Seal to the coolant tank 3 days ago and I have NOT experienced the knocking at startup once! The car is running great and I am hopeful that this stands strong. My engine oil is not milkshake, it's sludgy. Still oily. Now that I've added the K Seal and haven't experienced any knocking, I am going to use Mac's Engine Fast Flush & then do an oil change. I will report back with updates. Thanks community!
Start saving your money to replace the heater core, radiator, coolant pump, thermostat, small hoses, and engine..... That was the WORSE thing you could have done. It's even worse that not replacing the head gasket. It clogs up all the smaller passages. Extremely difficult to clean it out. It's kind of like taking an pain pill, but not resolving the CAUSE of the pain.
