Hey buddy, I've just changed the following sensors on my Sapphire mate as it's mid summer over here in New Zealand.
These four senosrs should be a good start if you want to make sure everything is all good under the hood.
* 2WD Fan Switch - Finnis: 7001614
* 2WD Temperature gauge sender - Finnis Code: 6145143
* 2WD ECU temperature sender - Finnis Code: 1639283
* 2WD Thermostat - Finnis Code: 1635905