Prius, overheating P1150. Coolant loss. Replaced Everything

I am getting a P1150 code on a 06 Prius (240k). Red Triangle and temp light come on after about 15min of driving (no heat). I have taken it to the dealer. They said the Coolant control valve (stuck) and waterpump (leaking) needed replacing. I replaced both of these myself along with the temp sensor and radiator cap, but the problem persisted. Coolant is also shooting out of the overflow hose in the reservoir tank when car warms up. I just took it to a different shop yesterday because I was assuming I could not get all of the air bled out of my system. They charged me $200 and said there was quite a bit of air in the system. The first thing I did when starting my Prius was to check the heat, no heat. I drove it home and immediately noticed there was yet again coolant spitting out of the overflow tube. I didn't want to believe this was happening again. I drove it to work this morning (15min drive) and the red triangle and temp light came back on. Please help me. I have spent 3 weeks working on this and $500.

I now have been driving it with the radiator cap loose so the pressure does not build up and spit the coolant out. This works for short drives, but I've noticed my coolant is disappearing quickly. No visible coolant on the ground or anywhere in the engine bay.

 

Thanks for your response. I have checked the oil over the past 4 weeks (since this started) and it has looked fine (color & level). I also had the head gasket tested by a reputable shop.

 

I forgot to add that to the list. I did change the radiator cap. That was the first thing I did.

 

I took the car back to the Toyota dealer yesterday. I listed off everything I replaced and told them to figure out what's going on. They tested the head gasket (again), and it was fine. They called me a few hours later and said my radiator itself is actually leaking. I'm not sure i totally believe them since I have been looking at the radiator on a daily basis for the last month and a half trying to locate a leak. I'll go pick up a radiator for $100 and give it shot I guess.

 

Hi Patrick. I would have, but by the time I got back to the dealer to pick it up, they were closed. Yesterday was Sunday so they were closed as well.

Yesterday evening I zip-tied an empty beer bottle into the engine compartment and stuck the overflow tube into it. I wanted to stop the coolant from leaking out of there. When I went outside this morning I checked the bottle and it was about half full, but there was coolant on the ground. Maybe this means i DO have a leak coming from somewhere (the radiator like the dealer said??)

 

After having 3 technicians look at my head gasket and saying it's fine, I'm going to rule it out for now. If the radiator is leaking is it possible that my system is sucking in air, thus causing the clog along with the leak? I just read this below thread about the filler neck leaking where it meets the radiator itself. I am going to inspect this tonight:

Leak by coolant filler pipe - 2005 | PriusChat

PS: The one thing I haven't checked is the thermostat.

 

Well, my radiator arrived last week and I installed it on Saturday (not fun). Needless to say, this was also not my problem. I could see where the Toyota dealer said my radiator was leaking, but it was just some tiny build up. I topped off the coolant after install, did my best bleeding the air out and drove it around for about 45min. It was fine, until the following morning. This is what keeps happening to me. After I top off the coolant in the radiator cap side the car runs fine because there is coolant in the radiator. By the time the next day rolls around then there's no longer coolant in the radiator and my light comes back on. Now I have changed almost everything in this system except for the thermostat. I'm so frustrated at this point I just want to trade it in for nothing.

 

Right. I run it for a little bit with heat on max, add more coolant, squeeze hoses....repeat etc

 

Well, finally it was confirmed that it's a head gasket. The engine combustion is actually leaking into my coolant thus causing the coolant to push out through the overflow tube (Augustus88 was right). I cannot afford to have anyone do this job for me $2000+ for a car with 240k. I have it decommissioned for the time being as I try to decide what to do with it. I was thinking about topping it off with coolant and trying to trade it into a dealer? Otherwise I'd just have to donate it and hope I get some money back from the government at the end of the year.

Is this is really hard job to try to do myself? Touching the electric motor kind of scares me. Should I maybe try some sort of head gasket sealer like Steel Seal? I know this probably won't work, but worth a shot? All in all, I spent about $750 in parts and diagnoses just to get to this point. Any suggestions would be greatly appreciated.