Hi, I have had a Doblo 1.9 tdi 57 plate for about 2 years. Just recently, it seems to have started overheating going uphill.the first time I checked the coolant. was on minimum but not boiling over. topped it up. the next time I checked the oil and topped that up . It did it again, saying "max temperature reached. Switch off engine". When I got a chance to stop, having gone downhill by then. the fans\are working OK. The ambient temperature was quite high at the time, but it still creeps up slightly going uphill. Wondered if anyone had any ideas about what \areas to check

Hi.
Low coolant and low oil..

That will limit heat dispersal.

Is the gauge also showing HOT when the message occurs ?

Is the thermostat ok? Radiator not clogged?

You have a coolant leak. Check radiator and all steel pipes especially the one across front of engine block.

If you cannot find the problem, get one of these to check for head gasket failure.

https://www.ebay.co.uk/itm/BT-3-50ml-BLOCK-COMBUSTION-LEAK-TESTER-KIT-CO2-BLOCK-HEAD-GASKET-TEST-FLUID-ac/283484512010?epid=11026959824&hash=item4200fe5f0a:g:MuUAAOSwLEtYi8Gi