overheating 300tdt
 

My 87 300tdt overheats when stopped in traffic. I have replaced thermostat twice, no change. Water pump is 2 yrs old. If I am stopped in traffic in the winter, the heat stops until I start moving, then starts again. if I am stopped in summer, I have to rev engine to 2-3,000 rpms before temp starts to go down. Does anyone have any ideas? I also replaced the clutch fan, no change!

Depending on your definition of overheating (there are some on this forum that panic if the temp goes to 90C), and assuming the coolant temp comes back to normal when you begin moving, you auxilary fan may not be working and/or the radiator has become clogged with bugs/debris over the years.

As far as losing heat in the winter the auxilary water pump is probably not working.

My 82 300TD did this.
Check the radiator. If it is origanal it may be collapsing. If you have a thermometer, IR would be the best. Check the temp of the radiator at various places on it. Mine had the center section collapsing and you could "feel" a cooler spot in the center. If its this then its time for a new radiator. If its original then after 16 years this could be the problem.

Dave