I have a 2006 9400i international semi truck, I am not getting any heat, could it be thermostat or heating core?

SOURCE: not getting heat in cab

Is the blower running at all? Also, make sure the main air intake vent is free of obstructions.

Also, a vacuum leak could cause the actuator to not function correctly. I'd check into the vacuum lines if all else fails. I've had too many cars here with heat/air problems due to vacuum loss and the actuators not switching correctly.

SOURCE: heat 2001 dodge durango

a bad heater core will just leak. it could leak alot. do you ever smell antifreeze? check the coolant level. it can get pretty low before it will overheat. the thermostat should be ok but there could be corrosion. when you had the water pump replaced was the cooling system flushed? 2001, its probably due for a flush. what coolant does it take? (green or orange)

SOURCE: No Heat and Overheating in 1999 Chevy Silverado

After replacing the thermostat, you must bleed the air from the cooling system.

To bleed air from the 2.2L and 2.5L engines, remove the plug or sensor on the top of the thermostat housing. Fill the radiator with coolant until the coolant comes out the hole. Since the plug is made out of steel and the thermostat housing is aluminum, it is a good idea to apply an anti-seizing compound or Teflon® tape on the plug threads prior to installation. Install the plug and continue to fill the radiator. This will vent all trapped air from the engine.

Any trapped air in the heating system will have to be displaced by coolant. Once the cooling system is filled, with the radiator cap off, turn of the heater at it's highest setting. Start the engine and allow it to reach operating temp. You should see a drop in the coolant level as the air in the heating system is displaced by coolant. Add coolant to the proper level and replace the radiator cap.

Keep a close eye on the coolant level for at least the next couple of weeks. The cooling system is a "closed" system. Any significant decrease in coolant level indicates a problem.

If you have any questions, let me know.

Please take the time to rate this solution.

Drive safe and be warm.

clarkco

SOURCE: 2002 dodge 1500 Changed radiator, thermostat, and hoses. No heat

Why was radiator replaced?Did it have heat before ? If it was plugged, the heater core may also be plugged. Try flushing it with a water hose in both directions. I dont know why the botton radiator hose would be cold, the radiator should be a uniform temp and the air coming through the radiator should be HOT, when the engine is at operating temp. What condition was the old coolant? if it was rusty, the water pump may have lower flow than normal.

SOURCE: Have no heat. Have replaced heater core,

I don't know your vehicle, but does it have a blower door tucked in where the heater core is? If it DOES and that's broken then it could be the whole problem. It would mean it isn't switching from the A/C side of things to the heat side of them. Hope this helps, good luck! Also, just looked up the proper name for what I'm talking about, it's called a "blend door" and I think your car has one. It's what I would check, again, good luck!