Temp fluctuations

[david7307]

This morning while pulling the caravan I noticed my water temp fluctuate from normal to low ,water levels on header tank are ok and none used ,and motor running ok no miss firing
I thought it may be thermostat playing up any info

[V8Ian]

Thermostat or sensor, mine does the same occasionally.

[simonmelb]

If it’s a TD5, common cause is failing insulation where the wiring goes around the front of the head.

[Tins]

If it's the factory gauge, fit another. The factory one is useless, you cannot trust it.