Big Radiator Problem! diesel down!

[EvergreenRanch]

ok boys i think i caught this fairly early on so im hoping there isnt too much damage if any. Engine prolly only ran for a couple hours in this condition. This is just an educated guess, but i think only thing wrong is a stuck thermostat. pulled it last night and it looked pretty much done for. i had two options as far as what themostat to put back in. i made a few phone calls and no one had either of the thermostats that i have seen posted here on the board. so i made more calls. Standt (sp?) makes one that is factory spec. and i found one. its a 195* operating temp and it looked extremly well made and engineered. all measurable dimensions were compared against the one i removed with a micrometer and its identical.

Ok next issue however. if the issue is not the tstat, what should i do? little bit more background: way i figured it out was there was high temp at top of radiator after a short distance, so out of habit i checked the lower return hose and it was cold. major red flag. Could this be a blocked radiator? if so whats my course of action? there was plenty of coolant behind the tstat when i pulled it which is why im wondering if it could be a block in the radiator.

what should i and can i check to see if damage has been done? i know you can fry pistons and rings with too much heat, but is there anything specific about our engines that i should change, replace, do anything to after this.

What is the Worst Case Scenario?


Also: is anyone near Contra Costa County California? East San Francisco Bay Area?

 

[Mont91]

There is a coolant bypass in the thermostat housing that allowes a small amount of coolant to bypass the stat. This can make the upper hose and tank feel hot with a closed stat. A stat stuck partially open will also do this. How long was the temp gauge pegged with the light on?

 

[94f450sd]

your lower hose isalways gonna be cooler than the top hose.cool coolant flows from the bottom of the radiator through the bottom hose into the engine then hot coolant flows from the top hose to the top of the radiator.hows your water pump?ive seen water pumps with rotted impellers cause an ice cold bottom hose and a hot top hose though.

 

[EvergreenRanch]

UPDATE

just the thermostat....water ran through the radiator just fine on flush. temps normal now with equal heat top and bottom