Did you put the right Thermostat in??? I'm not trying to be a smart Read below.

I've had to go directly to a Ford dealer because the other chain stores will often cross referance to the 7.3 International shorter style of thermostat. If they gave you the wrong one it will be too short to seal off properly and never warm up. Full flow hot or cold.

 

Rechecked the thermostat against one from the dealership TOTALLY DIFFRENT it was shorter, no burp hole, and had a heaver spring w/tight coils. Changed to one from the ford dealership.
The engine heated up [gauge did'nt move] went to put water in the resovior and notice oil mixed in with the water, pulled the oil dip stick oil looked fine. Even changed the oil no water in it. I put 2 bottles of radiator flush and let it idle for 30 minutes drained it put in fresh water still oil droplets showed back in the reservior. Engine now over heats. WHAT'S NEXT? :argh

 

How hot is it getting?? Headgasket maybe, how many miles and is it stock, modded??

 

Flush may have finished the head gaskets, as noted above. When the engine is fully cooled down, remove the cap, and top off the system. If coolant flows out while turning over, head gaskets are leaking.

 

the coolant does push back,when the engine is running. So i just purchased another engine with 160,000 miles. My plan is to install this engine and have the other rebuilt. Any recommendations for perfromance/durability is appericated. also thanks for all the help in this thread....tony