03 f250 Lariat no cab heat

[fastback4]

My 6.0, 82,000 mile diesel truck is not a daily driver so i am blessed that it is only used to haul our small camper during the summer months. During a short 25 mile trip there was no heat in the cab. I played with the controls, listened to the vents open and close ( floor, front vents, defrost vent ) heat gauge reads in the middle. Got it home, looked at the radiator fill bottle and it was right at the top of the cap. No coolant leakage anywhere in sight so i shut the hood and plugged it in to the block heater for the night. How should i diagnose this further today.........Tom

 

[blacksnapon]

My 6.0, 82,000 mile diesel truck is not a daily driver so i am blessed that it is only used to haul our small camper during the summer months. During a short 25 mile trip there was no heat in the cab. I played with the controls, listened to the vents open and close ( floor, front vents, defrost vent ) heat gauge reads in the middle. Got it home, looked at the radiator fill bottle and it was right at the top of the cap. No coolant leakage anywhere in sight so i shut the hood and plugged it in to the block heater for the night. How should i diagnose this further today.........Tom

Theres a valve on the passenger side top of the engine in one of the heater hoses. It has a vacuum line going to it. Make sure that the vacuum line is on it. Might check how warm both of the heater hoses are on the cowl side of that valve.

 

[fastback4]

Drove the truck 3 miles after it warmed up. Both heater hoses are very warm but not hot to touch. There is no valve attached to either hose. At one end both hoses go into the firewall. At the other ends, one hose goes to top of front cover, left side of motor standing in front of motor, the other goes around the back of motor down the right side of motor. Can't tell what it's attached to. Top radiator hose is hot but bottom hose is cold.. Is this the symptoms of a thermostat gone bad?

 

[blacksnapon]

Drove the truck 3 miles after it warmed up. Both heater hoses are very warm but not hot to touch. There is no valve attached to either hose. At one end both hoses go into the firewall. At the other ends, one hose goes to top of front cover, left side of motor standing in front of motor, the other goes around the back of motor down the right side of motor. Can't tell what it's attached to. Top radiator hose is hot but bottom hose is cold.. Is this the symptoms of a thermostat gone bad?

Nope, plugged up heater core. You might try removing both hoses and using a garden hose, flush the core, then backflush it. Its worth a shot!

 

[fastback4]

I'll attempt this flush tomorrow...Thank you......Tom

 

[blacksnapon]

Drove the truck 3 miles after it warmed up. Both heater hoses are very warm but not hot to touch. There is no valve attached to either hose. At one end both hoses go into the firewall. At the other ends, one hose goes to top of front cover, left side of motor standing in front of motor, the other goes around the back of motor down the right side of motor. Can't tell what it's attached to. Top radiator hose is hot but bottom hose is cold.. Is this the symptoms of a thermostat gone bad?

Ok, I read that wrong, I thought you said heater hoses instead of radiator hoses. Yeah, thermostat, plugged radiator.