03 No heat?

[RavoHimself]

alright. so i bought an 03 and the het worked great when i got it. maybe a week ago the heat stopped. if you turn the selector from cold to hot you feel a marginal temp change. but not really. checked the hoses to and from the heater core and they are both hot. pulled the BDA and it rotates



i can only assume that the actuator is working properly because ive never had to deal with one. so where do i go from here?

 

[RavoHimself]

also. i checked that actuator on the coolant hose that goes up to the heater box thats down below the alternator. when i switch it to a/c it moves all the way up but when you switch it back the arm only gets about 2/3 of the way inline with the hose. is that the full swing or is it supposed to be inline? so far everything i've checked appears to be working. im getting really frustrated

 

[RonD]

Not familiar with the '03 4.0l heater setup.

Some Fords have a by-pass valve instead of the heat control valve on the heater hose.
This allows coolant to flow out of the water pump and into the intake when heat is set at cold.

So check the hoses at the firewall for heat, the by-pass valve can get stuck.

If both hoses are hot at the firewall then problem has to be in the blend door or ducting.

 

[RavoHimself]

the only valve is down low on one of the heater hoses. i checked that one and it does move when you switch between ac and heat. both hoses are hot and the blend door rotates. that's why im so confused now

 

[RonD]

Valve on heater hose should move when you change Temp(Climate control) from Cold(valve closed) to Hot(valve open)

Only when valve is open should both heater hoses be hot.

I would set temp control to cold and start the cold engine, then wait and feel the hoses, only one should heat up and heat up slowly since there is no circulation.

Once engine temp is up to about 1/4 on the gauge, set temp control to Hot(open the valve) then check how long the other hose takes to heat up, should be almost instantly.
And both hoses should now be the same temp as the Upper radiator hose, so very hot.

If heat up of hose is slow then core is clogged, and that's why temp is low inside.
You can try to backflush the core, it does work but takes some time.
Google: backflush heater core

All heater cores are pretty much the same when backflushing so doesn't have to be a "how-to" for a Ford heater core.

 

[RavoHimself]

i dont think thats how that valve works. one of my buddys also has an 03 and we checked his to see if it moved when you adjusted the heat and it didnt move. only when you switch between ac and heat. same as mine

 

[RavoHimself]

i did just try checking the hoses from a cold start though. last time i checked i had just been driving for a while. this time i clearly noticed one hose was colder than the other. looks like im gonna be backflushing the heater core tomorrow. at this point that seems like the only thing left that it can be

 

[RavoHimself]

just tried the backflush. water seemed to flow through fine and nothing gross came out. tried it anyway and still no heat. still have one cold hose

 

[RonD]

Cold hose means no flow, so valve is the next stop