Problem with Engine Coolant System

I have driven my 2004 Prius for a bit over 136k miles now with no major issues and no accidents. Recently my problem light came on and indicated my coolant was overheating. I took it into shop A and they said I had a leaky water pump which was causing the problem, so I had them fix it. The problem light came back on the drive home so I decided to take it into a Toyota dealer to have them take a look at it. So they tell me shop A butchered the water pump install and that the problem was air pockets in my coolant. They estimate fixing the water pump and flushing/replacing coolant at $330 and will write me a letter to try and get a refund from shop A. I say go ahead and do it. This was pretty late into the day and they tell me they'll have to keep the car overnight and finish up tomorrow (yesterday). So yesterday I get a call and they say everything is looking good, the system is staying pressurized and there are no leaks but they need to run some extra tests and update firmware and it's actually going to cost closer to $440 with the new labor charges. They seem pretty straight forward so I give them the go ahead. A few hours later I get a call that they still can't clear a code (didn't tell me which one, I didn't ask) and that they would need to keep it again tonight (yesterday night) and run some type of 8-9 hour test on it. There was no upping of the estimate this time so I said okay. A few hours after that, right around their closing time, I get a call and they say that they have determined the cause of the problem to be a dented coolant tank. He said that the temperature of the coolant is supposed to be ~44 but 3 minutes into starting the car it was up 5 degrees and within 10 minutes it was up 15 degrees. He asked how long ago I was in an accident, which I replied I never was and asked how could it be dented if there was never an accident? He said he would have to ask the mechanic tomorrow (today) and he would get back to me. He also said it would be an $1800 repair which puts the total value of work at more than half of what the car is worth. Am I getting taken for a ride here?

To explain what was happening with the car and the reason I took it in is below.

Around 10 minutes into driving time my problem light would come on with the coolant overheating warning. This would only happen if the engine was engaged and if I was coasting with full electricity or at a stoplight this light would not come on. The heater also stopped working around this time as it just blew cold air and no warm air. For the first 15 minutes the car alert would come and go, but afterwards it was a constant alert light. When I opened the hood there was no steam, no coolant leaks I could see, nothing that would alert you there was a major problem. I'm not even close to anything resembling a mechanic so I have no idea what to look for or what the problem could be. Any help is greatly appreciated.

 

Thanks for taking the time to reply. I gave both threads a read and am planning to go see the car around noon today. The shop is saying that the tank is stored in the front driver's side of the car and I was side swiped there about two years ago. It was nothing major, as it was a car backing out of a driveway that made contact and immediately stopped. There was cosmetic damage on the outside but to my eye no internal damage. The mechanic is saying there is a 2" dent in the tank and I am planning on taking a look to check for myself.

Regardless of whether there is a dent or not, I will decline the $1800 repair for now as it looks like the coolant tanks are going for ~$400 on Ebay. Assuming the problem does indeed exist with the coolant tank I will try and research how hard it would be for a DIY coolant tank swap. I'll also plan on checking the thermostat and pump prior to attempting any of this, and I'll try and get some pictures to post here. Does this sound like a good plan of action?

 

Thanks for the tip Joe. I'll ask the mechanic if there is a leak on the tank when I head in today. I was told previously that everything was holding pressure and I believe I was told there were no leaks. I updated my location to reflect my living in Chattanooga, TN. Thanks again!

 

Just got back from the shop. It is a Toyota dealer's service department. The mechanic showed me the dents and had a computer hooked up that was monitoring the valves opening/closing and the temperatures. I wish I would have written the numbers down as I can't remember what they were now.

The only error code that was getting thrown was P1151 and I believe he said that was clear as they emptied the tank of air which was not done at Shop A, he said. I did make sure to ask whether or not it had a leak and he said no, it was holding pressure fine, and that he would put the car back together and see how it drives if he was me. So, I'm going to take that advice and see how it goes. He said the problem alert I was getting should be gone as it was probably due to the air in the tank, and that the heater also works now.

I took some pictures of the tank which shows the dents which I'll post as well.

First picture is standing facing the front of the car from the driver's side.


This picture shows the dent in the back of the tank caused by impact to the front.



The below picture is from the back side of the tank.

 

When I went and talked to the shop, I got to talk with the mechanic one on one and he said that he would if it was him, he would not spend the $1800 himself and would drive on it to see if the problem is fixed. He did reiterate there was no leak and the tank itself was holding pressure.

 

The Toyota shop said they would write out a letter stating that the pump was installed incorrectly (mechanic said they didn't push the air out at all). I'm planning on taking that letter in with me to the first shop and trying to get some type of refund. The reason I didn't take it back to the original shop is because they were supposed to have had fixed the problem by installing a new water pump, but the problem wasn't fixed. Rather than keep taking it to them to try and fix it one step at a time, I figured I would take it to a Toyota shop since they would have more experience working on the Prius in general. The Toyota mechanic made it pretty clear that the person that installed the pump didn't seem to have a clue of what they were doing and left air in the tank.