Right now in the summer if I set the truck to hot setting it runs hot. Last Christmas was -30 out and was on the highway, the truck barely ran Luke warm to keep the windshield defrosted ! I have a grill cover and cardboard infront of the rad to keep it as warm as I can. Both hoses are new, I bought a better shape rad from the wreckers and the heatercore was done recently aswell. There is a 195 degree thermostat in there now would a 205 degree help ? It's been awhile since thermostat was done so maybe try that ? I have a spill free funnel kit and tried raising the truck up and burped the coolant as best as I could to prevent air lock. Heater core hoses seem fine aswell. The truck is a 96 with the 5.9 but has a rebuilt 2001 motor in it. I had to tap in the second sensor for the gauge so I could actually read my temperature. For whatever reason it always stays a little above the middle mark when at operating temp. What else can it be? I need proper heat this winter, it blows my mind why it works right now but not when it's cold. Any help is appreciated Thank you !

 

Personally, I wouldn't go any higher than a 195 degree thermostat. Just make sure that you're using a good quality thermostat, such as a Stant Superstat. The heater core could possibly be plugged a bit. Try checking the inlet and outlet hoses at the heater core at the firewall with a laser thermometer to see if there is a difference in temperatures between the two heater hoses. The blend door not working properly can also cause heating issues.

 

thank you for the reply. I replaced the heater core after I noticed the low heat issue that was occurring. As far as blend door. How does that matter if it blows hot right now but not in the winter ? These trucks just don't like the cold ?

 

Might be an air pocket in the heater core yet as well.

As for 'hot during the summer'... Yeah, not a surprise there, as the air passing thru is already fairly warm. When the air is -30 degrees..... it's got a much longer way to go to be considered 'warm'.

My Dodge Conquest was like that..... if it was below zero, you could see out the windshield, or, your toes could be warm..... but, not both.

 

Ya im stumped man! I really need heat this winter for hunting season. Thank god the truck isnt a daily driver but its boogled my mind i dont know where else to look. Only other thing im thinking of doing would be brinignng it in to be professionally flushed

 

What is the gauge reading when at operating temp in -30?

 

How old is the radiator, ever been removed and reverse flushed and capacity checked? I run a stock 195* thermostat, but haven't lived in below 0* weather for some time. Holes in the floor, door seals good? Is your thermostat working properly? How about the fan clutch. The heater core and the engine provide the hot water, not the radiator, for cabin heat. The thermostat is what regulates the temperature between the block and radiator. If the engine isn't getting up to temp, then the thermostat isn't working properly or an air pocket is present. Ever think about putting a block heater on? Worked wonders for my 68 wagon 440.

 

It's at operating temp. We'll technically a little hotter pass the middle. Ever since I installed the sending unit that's what it reads on the dash and stays at that temp

 

Was thinking of replacing the thermostat and taking it to a shop to get back flushed. I replaced the heater core and it didn't help. How does the fan clutch help with the heat ?

 

The blend door lets outside air in to help control the temperature. There are seals on it that deteriorate over time that may be allowing cold air to get into your truck during the winter and negating the warmth of the heater core. In your case, I would check those heater hoses to determine what the temperatures are going into and out of the heater core with the heater blower running on high. I would also change the thermostat and be sure to use a high quality thermostat, such as a 195 degree Stant Superstat. You can pickup a temperature gun pretty cheap at Harbor Freight - https://www.harborfreight.com/infrar...ter-93984.html