Antifreeze leak.

[78F250SCCS]

Antifreeze is leaking inside my cab. I'm thinking its my heater core. I've never had to dig into the heater box on these trucks so I don't know where I should start to look.

 

[Fellro]

If it is in the cab, the only way in is from the heater core. If you have a non-factory air truck, then you have to take the dash out. If you have a factory air truck, then the air box on the outside of the firewall is where the core is.

 

[LEB Ben]

Tell tale sign of the heater core...you'll probably start noticing a green fog forming on the lower part of your windshield as well. It's not too difficult of a job to to do, even easier if your rig doesn't have A/C...but if it does, this is the direction I always use:

http://www.ncspecialties.com/autobody/heater/index.htm

 

[78F250SCCS]

I don't have A/C. I pulled apart a cab a couple of years ago but I don't remember how I got the air box out. I think I kept it from the parts truck. I haven't been getting the foggy window, It smelled like antifreeze in my truck and I pulled up the floor mat and saw where it was coming from. I think I have only used the heater twice since I've owned the truck.

 

[Mil1ion]

Check the hose where it attaches to the heater core tube under the hood first.
Sometimes the rubber cracks and coolant leaks from there into the cab.

 

[the milk man]

Hey I just had the same problem replaced my heater core loosened passenger side bolt for dash and middle bolt for dash wiggled right out replaced it with new on one $30 and an hour and u will be good to go

 

[78F250SCCS]

Good to hear its not that big of a job. Thanks

 

[78F250SCCS]

I priced out a heater core at NAPA, and here it is $70, and a water pump, new is $80, and the re-man water pump with the core is $50. I'm going to be parking the 78 soon for the winter, so I'll buy the parts over the winter.