This is for a buddy of mine. The truck is an '83 F-250 4x4, all stock except a Bank's turbo kit with exhaust.

He's been having heat issues in the cab for a few months. He recently replaced the t-stat due to engine temp reading low. Now, the cab blows warm, but still has low engine temp. These are the readings taken:
Heater hoses going into cab: 130
Rad hose, top of engine: 140
Read hose, top of rad: 138
Lower Rad hose, at rad: 57
Lower rad hose at engine connection: 89
Outside temp when readings taken: 12

Any ideas? He wonders if there is a second t-stat. I'm a PSD guy, and have only messed with IDI injection systems. Any input or guidance would be appreciated.

 

I dont know what the stock thermostat in that engine is rated at, but in mine I always ran a 190 degree thermostat. good heat in cab, and engine temp on guage was always on the lower side of normal.

 

I have an 86 and my tranny tunnel gets so hot you could cook on it haha. Maybe he is just missing some heat pad. I know is I am