A couple of weeks ago error code P1151 popped up. This code indicates an issue with the Coolant Heat Storage (CHS) system. Anyway, I then noticed that there was almost no coolant in my radiator reservoir so I filled that up and reset the code. The code has not resurfaced. Yesterday, I checked the radiator reservoir again and it was just below the low mark. I again filled it up and then on further examination of the engine bay, I noticed pink residue from coolant on what looks like a pump - initially I thought it might be the inverter water pump, but it appears to be the 3 way coolant control valve. I started the car up and drove it around the block - I couldn't see any coolant actively leaking from this valve or the connecting hoses. I still haven't had any codes return. Does anyone have any tips for replacing this 3 way valve. How about for bleeding afterwards - can I assume that this valve is only connected to the engine coolant loop and not the inverter loop? I'm also thinking of purchasing the Autel AP200 to do the bleeding procedure afterwards - anyone have success using this tool? I've attached pics taken from the top view, facing the front of the car: the pump is in front/below the right side of the inverter. Additional pics taken after cleaning off the reservoir as well as a pic from under the car.
That is probably where it is leaking, but since you didn't actually see any fluid there, you might want to find out for sure before replacing it. That could be from an old leak. Knock off the bigger chunks and then wash off the rest. If it comes back, now you know for sure. You should also get a mirror and inspect the water pump, the one that is belt driven over on the passenger side of the motor. In any case, keep a close eye on the fluid level. You should top it off in the radiator neck (don't just assume that is the level in there) and then mark the halfway point in the overflow tank with a Sharpie, and fill to that point. You can then just check the level against that mark each morning. If there is a little trapped air, and there probably is given the code you saw, the level in the overflow will fall a bit for a couple of days, just bring it back to the mark. Run the heater a few times, there could be air in there too. Once all the air is out it will be stable - if there are no leaks. As long as the tank doesn't empty the radiator should still be full to the top and following the overflow tank will be good enough. Hmm, or not. If there is a head gasket issue that can introduce gas into the cooling system. It can actually force fluid out of the overflow tube on the overflow tank. Which you may not ever actually witness since if it happens on the road it will just blow out under the car.
