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Hello,
So the guage went high and no fan cut in.
Mechanic sounds like an utter cnut for not telling you or fixing the issue even after getting the car back to replace the water pump.I'd check that the fan motor still turns, with the ignition off, so you can see if its free and not seized. Then if it free look at the thermoswitch. Looking at the photos here the thermoswitch is at the opposite of the water pipes, unplug the connecter and short the two terminals with a cable and see if the fan operates. If the fan operates then the thermoswitch has failed. If nothing happens so check the fuse isn't blown.
lynx-
@byjoshuawilliams find the fan thermostat switch on the radiator and bridge the wiring to see if the fan runs, then if that is OK make sure that part of the radiator is getting hot, thermostat opening/rad blocked etc. Fan switches are very common on VW's I used to fit loads of them when I worked at VW/Audi before my BMW days.
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I'll check the fan now. Just ran the car from cold with coolant cap off. A lot of bubbles coming out of coolant. Seemed to settle down after about 10 minutes and coolant dropped from top to empty. Then when I turned heating off it went mad and dumped coolant all over the floor. Opened heater up again and it settled down until I turned it off then went even more crazy and emptied most of the coolant on the floor. Bubbles all the time.... Pretty severe. Classic sign of head issues!
Radiator felt cool the whole time, car didn't overheated and rad pipes not over pressurised
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Tested both fan and wiring from thermoswitch to fan and both work fine. So presumably it's either the thermoswitch or a blocked rad. I can't see how either of these would cause the issues with the coolant pressure than. Are we saying it's two separate issues? Might as well get the thermostat out now and check that.
Fixedwheelnut
Jw89
Had another look at the last invoice from Dodgy Mechanic No.1 and he mentions that the coolant fan isn't working, so that is definitely a good place to start. Also that guage was in the red but no overheating warning light was coming on. What would possibly cause that? Could the two be linked?