I have a problem with over heating on a Volvo MD6A diesel.
When the engine is out of gear and running the temperature stays in the proper range. Lots of water out the exhaust. New thermostat, new impeller on raw water pump, and clear intake. However when the engine is in gear and under medium load the temperature gage eventually rises to high temp zone and then the needle drops back to normal for a few seconds then back up near to the red limit. It keeps repeating this and will near the red zone if the throttle is not reduced. If the throttle is reduced to a little above idle the temperature drops back to normal range while under light load. Any comments would help:hothead
When the engine is out of gear and running the temperature stays in the proper range. Lots of water out the exhaust. New thermostat, new impeller on raw water pump, and clear intake. However when the engine is in gear and under medium load the temperature gage eventually rises to high temp zone and then the needle drops back to normal for a few seconds then back up near to the red limit. It keeps repeating this and will near the red zone if the throttle is not reduced. If the throttle is reduced to a little above idle the temperature drops back to normal range while under light load. Any comments would help:hothead