So the last time I got my car serviced with the local dealer they gave me free nissan roadside assistance, so I gave them a call and they sent out RAC.
This morning when he arrived to my suprise the car started straight away, he put the heating onto max in the cabin and let the car run, he took the rad cap off and topped up coolant, apparently I had lost just under a litre. We let the car run till the normal running temp, meanwhile he checked the rad/fan fuses by the battery. Which were all fine.
The fan kicked in at a moderate speed and everything seemed normal, he then started to rule out the fault, he held the revs at 3000rpm now with the heating off, eventually the fans kicked in again at a higher speed. He checked both the coolant hoses and both were hot as well as the rad which meant it wasn't the thermostat sticking, he stated that if it was the thermostat then the right side of the rad as well as the right coolant hose (closest one to the dipstick) would not be hot.
That then ruled out the thermostat, fan and fuses. He then took the rad cap off and covered it with a rag to let any excess air out, nothing really found there.
At this point we found no faults, thermostat, fans and heating all working, the car had been running approx 40 mins now with temp gauge normal, as he was packing up and sorting his paperwork, he asked me switch then engine off, when I went to take the key out I noticed the temp had shot up to the max. We then switched car off and he said there can be one of two issues now that everything else has been ruled out
1. There is a blockage in the coolant system
or
2. The water pump is faulty
He then ruled out the blockage by saying if there was a blockage there would be no hot air coming through, which left he diagnosis being that it is a faulty water pump.
I rang up the 2 local nissan dealerships and got quoted the following for parts
1. Westway nissan Mill Hill NW7 £113 + vat
2. Glyn Hopkins Watford WD17 £129 Inc vat
I'm waiting on quote for labour as of yet.
The 2nd dealership also mentioned if I'm not 100% it is the water pump, I can pay £107 for them to diagnose the issue and if I do proceed with them doing the labour they will take the £107 off the total price.
Cheers for replies I'll keep you updated