1985 300D running hot

My 1985 300D always has been running on the cool side(barely hitting 80C)
Ordered a thermostat with a recent MB Source order and finally installed the other day while doing regular maintenance.Re-filled with MB coolant50/50 H20 and now it runs hot! (95-97C). What should I suspect first?
Thanks,
Michael

Forums

Diesel Engine Specific Aid

Chassis Model Number

W123

Running hot

Hi Michael. Was the thermostat you installed the same temperature value as the one you took out? Verify that for starters. Next make sure that you have got all the air out of the cooling system and that it is completely full. If your car has the expansion tank and no cap on the radiator undo the hose going to the top of the radiator. Then pour your 50/50 coolant/h2o into the hose as you hold it slightly upright. When it takes all the solution that it can, get it back on the neck quickly and tighten the clamp. If this is no help wait to see what the Guru(Kent)says.

1985 300D running hot

Yes, same type thermostat. I'll try the radiator upper hose method 1st. Thanks for the reply