Hi all, I have a partner van 1.9 dw on a 53 plate and its overheating, this started at the beginning of January and I can't get to the bottom of it. It was due a timing belt so I decided to replace the waterpump and the thermostat as I've had it since it was 4 1/2 years old and neither has been replaced, but it was still overheating, the funny thing is that the temp. gauge doesn't go up far (it will "overheat" after about 5 mins) and it drops right down and then flies up, then the beeping starts and the stop warning is flashing. The top and bottom hoses and the radiator are all stone cold and I have warm air through the heater, I have had the rad out and it is fine, no blockages whatsoever, I also knew that the maf sensor was faulty so replaced it when I changed the timing belt. I have a fault code reader but the instructions say that it will not work with my van as its a 53 plate (54 onwards only), but earlier in the week I plugged it in and managed to get a code - 0407 and it read " Remote permanent fault, Coolant temperature information incorrect value received. I looked it up to find it was for the egr, so I checked the egr valve and the egr solenoid valve to find that the solenoid valve was faulty, I replaced it today and its made no difference. Should point out that I checked the temp sender unit on top of the thermostat housing and its ok, wiring is also good. Does anyone have any idea what's causing it, be grateful for any advice. Thank you.