I have an 02 TD4.2T which overheats badly when towing caravan. I have had the radiator rodded and checked the thermostat - all OK. Replaced the oil in the thermo hub today. Used 2 18mL tubes of silicon oil (Toyota). The hub does not feel any different now than when it had minimal oil in it. Still wont kick in as temp rises.

Any thoughts? Any info greatly appreciated.

Spoons