I thought I'd tell you about another problem with the Ford Ranger. The cooler for the EGR valve fails, and when it does it pumps water into the motor and the conrods bend under the force. We had one in our workshop recently. We fitted a new cooler with the engine rebuild, and that also failed in a few weeks. Luckily we caught it this time, which saved the motor.
Thanks for the tip. We'll add that to our list of things to look out for on the Ranger. Presumably it's the same with the Mazda BT-50.