Hi my van temperature runs normal around town but once you go above 50mph it the temperature gauge shoots up rapidly and goes into reduced power, if you reduce your speed bk to below 30 it drops back to normal on the gauge and the power comes back.could this be a thermostat issue or fan?

Thanks for any advice

Hi,

Shouldn't be a fan issue. Plenty of airflow through the grill at 50+. Fan is needed more in town traffic.

Don't know whether the Transit has grille shutters? Worth checking they aren't permanently closed if so.

Not convinced it's a thermostat fault either as that should show up around town. Easy to test though, next time it overheats, pull over as soon as you can and feel the radiator. If it's stone cold then the thermostat is stuck closed.

Thanks I'll give it a go