UK Car Repair: Corsa overheating, vauxhall combo van, degreasing agent

Question
I have a 1999 Vauxhall Combo van with a 1.7 diesel engine. It seems to overheat even though ive had a new thermostat and fan switch fitted. The mechanic tells me they do run hot but its running at around 100 degrees according to the tempreture gauge most of the time.  

Answer
Flush and refill the cooling system. Use a degreasing agent on the radiator to clean any muck it may have accumulated.
Other than that, there is nothing you can really do about it unless you are willing to take it to the dealership and let them examine it. Diesels are not really known for running all that hot; I would be suspect of the diagnosis and see what another mechanic says.

Regards,

John