please guys, any opinions would be greatly appreciated. Yesterday while driving i noticed that my temp gague had risen from the always normal 90 up to 100-110 , when i got home i checked all levels , they were fine , i also noticed that the fan was not cutting in , also i saw slight seepage from around thermo housing and top rad hose is very stiff with pressure , i turned heater on full and temp returned to normal , i also fixed fan switch to remain on permantly but problem still exists , last resort is to remove thermostat as i cant afford expensive fix at the moment ...... any opinions would be great , thanks Dave (Dublin, Ireland)

You say fluid levels are ok....water has not dropped and oil is not grey, if these are ok I would check the thermostat in a pan of hot water and bring to the boil to see if it opens.

Another avenue is the water pump, the plastic impeller could have broken up!

oil looks fine and yes all levels good , i would have thought if impeller broke up the symptoms would be a lot worse , or it would make some sort of sound , car running and sounding great !! thanks for the reply benterrier...

Also check that both radiator fans work, but it does sound like the thermostat is stuck shut.

I have also recently had overheating problems, my thermostat was OK but the water pump impellers were all broken up. The car only overheated under severe provocation in traffic. My fans did not go round, but I am having a new fan control unit fitted on Wednesday which will hopefully solve the overheating problems. Does the coolant seem to flow when the engine is up to temperature? If not, it could indicate that your water pump is broken.

When the impellor goes on the TDi, it doesn't always break up. I know of more cases where the TDi impellor splines have just stripped, so that the shaft goes round and the impellor doesn't.

check the thermostat in a pan of hot water and bring to the boil to see if it opens.

That was my first thought but I wouldn't bother testing it, if you're gonna take it out just stick a new one in! Why mess about?

If you're that way inclined, you could also drain and flush the system out and put in new antifreeze too while you're at it.