Heater blowing Cold

[TexasAngel34]

Very strange, when the cold weather came only the back heat was working , now front and back are blowing cold... i know its not the heater core so im not sure what else to check... Any suggestions?

 

[bedrck46]

I would suspect that the heater cores may be clogged I say that because you state that only the back heat was working and now both are blowing cold. By you saying both are blowing I assume that the fans are running. I would start by checking the inlet and outlet temps to both heater cores and checking the heater hoses for any cold spots along the lengths. Also you state that its not the heater cores. Kindly explain how you know it isn't. What have you checked?

 

[TexasAngel34]

my roommate told me it wasnt the heater core... but i will have that checked as well as the hoses ... Thanks so much

 

[bedrck46]

keep the forum posted would like to know what you find
If you can also see what your coolant temp is?
Could also be a faulty t/stat or water pump.

 

[TexasAngel34]

will be checking tomorrow , will come back and update what i find out....

 

[BAD RONALD]

Check this out first:

1999 Expy 4.6 Heat FIXED! - You won't believe how! - Ford Truck Enthusiasts Forums

Could be a plumbing issue.

 

[gkelly]

Mine has the same problem pretty sure I need the heater core back flushed ..inlet gets hot outlet only gets warm

 

[BAD RONALD]

Mine has the same problem pretty sure I need the heater core back flushed ..inlet gets hot outlet only gets warm

It would be easy to check the restrictor before doing a back flush.

 

[KJ Beckenhauer]

I'm having the same issue with mine. I replaced the heater core, but the air is barely warm with the heat cranked up to Wrath of God.

I should note that I also replaced the blend door at the same time I replaced the heater core