Ranger Coolant Loss

Low coolant is never good. I had a similar thing with my old truck and a check engine light. Have you checked the radiator for leaks? What does the error code say specifically? How quickly is the coolant dropping?

The error code is just 'Coolant Level Too Low'. The coolant drops about 200ml every 500 km. I checked the radiator and found nothing. Would a pressure test help find subtle leaks?

200ml every 500km is more than normal. A pressure test is a great idea. But with that rate of coolant loss and a generic code, I’d have a shop look at it. It could be internal, and you don't want to risk engine damage. Better safe than sorry with a diesel.

I took the Ranger to a workshop. The pressure test showed a leak in the thermostat housing. The repair was 52€. It wasn’t a head gasket, and your advice helped prevent further issues. Thanks for the input.