I think I fixed my wife's car yesterday. It would boil over at idle, but the temp sensor says low temp. So what could it be? I tried a new radiator cap. Nope. I tried a new thermostat (which I think was at least a little at fault) but nope again. The last time it boiled over, I was there and I looked and the radiator fan was not blowing and all this steam was coming out. Aha! I've been here before. Bad solid state relay. But I thought about it and since the temp was at about 1/4 all the time and then when this happened it was approaching 1/2, I figured, may not be the relay but the temp sensor. So I replaced it, and ran the car. It immediately went over 1/4 and I thought OK, that's good. Then I hooked up my OBD-2 connector and saw that the temp was at 217. Then it went up to 218 and then down quite rapidly to 210. I went out and the fan was just shutting off. So I think I've got it word
mspart