im sure my mk2 16v never use to go above 102degrees (looking at the digital display) as the fan would kick in and bring it down to a stable temp if i was sitting in traffic it would usually fluctuate between 98-102. it now seems to be pushing 112 then the fan kicks in and stays between 108-112. is this an issuse with the thermostat switch on the rad? the strange thing is all this happened after the garage changed the water pump, maybe nothing to do with this at all, just thought i would ask if it is normal. two of the hoses on the cooling system burst in the same week. tom.
the MFA display shows oil temp not water temp. the rad thermo switch is what tells the fan to come on, when the water temp reaches a certain temperature. Therefore if you replace anything, I would go with a VW dealer thermo switch. I think you can get lower temperature thermo switches. the thermostat in the elbow below the water pump may be stuck shut. this means the water will never get through the radiator, but then the fan wont cut in.. it'll just blow pipes like you say happened. run the car and keep feeling the bottom rad hose, it should be cold till the coolant warms up, then the 'stat should open and it will fill the rad with hot water...
do you know if they changed the thermostat too or just the water pump. If they have fitted a new thermostat could be the wrong one?
