I am a real Toyota person. I am very disappointed in how Toyota deals with issues. I got a price from my mechanic - he said it would be around $3000.00 to fix, ouch. I'm not sure if car is even worth that much. I called Toyota and they said they do not fix the head gaskets they replace the motors in them for $6000.00, ball park. So is that like admitting that this issue is not worth fixing?

These cars are rated really good as used cars by consumer reports. They need to add that as of my experience until head gasket blows mine happened at a lot more miles than others in your complaints - 240,000 thousand miles. Fixed it with a liquid head gasket sealer for short term.

But it came back after car did not get driven for a while. I thought I had fixed it so I had easy cure for the problem so I bought another one with less miles. When it came back now I just want to get rid of both of them. But I feel bad that I am selling a car to some one that may have issues down the road.

Will try to put more head gasket sealer and hope it works. Just try not to let it sit. My friends daughters blew up on her 200,000 miles. So is this something that will happen eventually to all Toyota Hybrids?

Mileage was high (190k), way out of warranty.

Took car to dealer after check engine light and rough, very shaky engine starts. Dealer found cylinder misfire codes & cleared.

Misfire reoccurred. Dealer replaced EGR valve (I paid my right arm for it). Misfire reoccurred. Dealer replaced intake manifold. (I paid my left leg for it) Misfire reoccurred. Dealer replaced spark plugs and cleaned fuel injectors. (no charge). Misfire reoccurred. Deeper diagnosis found coolant leaking to one of the cylinders. Dealer wanted almost $4k to replace head gasket.

Took to local shop. They replaced gasket, machined/surfaced head and replaced all 4 tires for $3200. Been another 20K miles. No issues.

Moral of the story is that you don't need a Prius dealer shop to service these cars. Electric drive service might need their 'expertise', but check with your local guy first. Sounds like head gasket issues aren't unusual on this model Prius.

extremely loud engine knocking at start-up

Yesterday was the fourth time experiencing this issue. Having checked on line at other sites, it appears to be a common issue. Most seem to suggest that the problem usually occurs when the car is started and shut down soon after, which seems to concur with 2 of my experiences. 2 of the 4 times this loud knocking noise at start up occurred, it was after the car was started to move slightly forward in driveway. I'm not as sure on the details of the other 2 experiences. There was loud knocking and engine was shaking. Definitely something Toyota should address, if they want to live up the hype about how great the Prius is. So far my opinion is that the hype is just that; hype, not based on anything truly factual. My opinion of the Prius is that it is average at best, probably under par. I have taken very good care of this car; no abuse.