Hello we have a 1993 ranger 4.3 lt ext cab and went through last winter with little heat. Last week we flushed the system and it was were dirty, rusty and lots of slug in the system. We still had no heat so we have changed the thermostat and that made little difference. We then changed the water pump thinking it was all gumed up and or blocked and ran a wire through the ports of the engine housing and it seemed clear. We then flushed the heater core to the point it was running clean through both tubes. Still little heat, heated up a bit idling but we lost heat while driving. We have also changed the rad cap and put cardboard in front of the rad but that did not make too much difference. We have no air on this truck and to move all the inside controls you can hear the vents opening and closing properly and with the fan on we can send heat from the defrost to the dash /panel and down to the floor. The heater core and rad hoses heat up well and we changed the wire to the heat gauge and it now registers and hovers around half, this we changed after we first flushed the system. My mechanic and the owner of the local rad shop are kind of going what the hell. The rad looks fine and seems to heat up well, all the vents seem to work well and I don't think this truck has a blend door because we have no air conditioning and that is listed as a common problem. Has anyone run into a similar problem with this same vehicle. Any suggestions. Thankyou ian ps a nice donation will be sent for the correct solution to this problem.