Heater motor I have a 2001 F250 Superduty 7.3l diesel truck. In the mornings lately, it has been cold and i let the truck run to warm up but the motor doesn't blow and air out. Once the truck reaches a certain temperature, the heater motor starts working. Is that normal, do you have any suggestions if it is a problem. Blows air fine on hot days for A/C.

Not knowing your experience with diesel motors,if the glow plugs are not being allowed to cycle it makes starting the motor cold much harder. If it has a block heater package that also helps to plug in. Keeps the coolant warm and in turn keeps the motor warm.

which fan? if you are talking about the engine fan, it will run on until the temperature drops, but if you are talking about the heater fan, thats not right

I had a problem with vacuum in my F250 diesel. It had a new vacuum pump but would kick out of cruise control every time the vacuum pressure dropped. It turned out to be the vacuum reserve cannister had holes in it.

Seems you reach a tipping point and then all the vacuum systems mess up. You might want to check the reserve cannister and any vacuum servo your 4x4 might have. You can check most of the vacuum stuff with the engine OFF using a vacuum pump. You could have a leaking vacuum pot operating the ductwork. Check your diesel vacuum pump for output and loose belts.

check your glow plug relay! located on the right side head

make sure the hoses down by the right side kick panel didn't come unplug from someones feet. then make sure the vaccum pump on the right side fender is working. when there is no vaccum it will go to defrost

your fuel shut off valve is sticking or is not getting current from the relay,Thats were I would start looking,I hope this helps you,If it does it all the time it will be easy to find but if it just does it every once in awhile it may be hard to find,and if you are in really cold weather I would really look at the fuel solinold,,please get back with me with a little more info and maybe I can help you more,please do not forget to vote on this solution

if you have the 6.0 then the filters are located on top on the motor right beside your oil filter and under the drivers side on the fuel pump, check to see if you have diesel in your bowl where the fuel filter is, no diesel in there your fuel pump might be dead, check fuses to fuel pump and check relay on the passengers side kicker panel, check your owners manual

check to see if coolant fans is working. they have run to cool down the 134 refrigerant in condenser.back down to liquid state .so it can run the cycle again.

cant start deisel 3.0 lilter sounds like there is no fuel getting to the engine

to what?