Overheating !!!!

[Slugger]

Just travelled about 10 miles in my surf and all of a sudden the temp gauge shot up into the red. Pulled over straight away and checked the coolant levels. The reservoir was full and boiling but when i removed the rad cap it was empty. Left for about half hour and filled back up and drove back home. Checked again and no water under the rad cap but the reservoir was full and boiling again. Cannot see any leaks and will check again in a bit but i did notice that it kind of juddered a bit yesterday when i started up and there was a little bit of white smoke on start up but not whilst driving. It also gave a few puffs of white smoke when i started up again after it overheated. Any ideas/pointers as to what it could be

[marky]

1st thing to do is change thermostat & rad cap as these can fail

[Slugger]

1st thing to do is change thermostat & rad cap as these can fail

Are these off the shelf items from local auto spares shops or will i have to get them from Milners ??

[marky]

0.9 Bar Rad cap from Halfrauds i got thermostat from milners. Some motor factors may have them.