Can anyone tell me which is the correct heater hose connection on a 2003 Ford Ranger Edge with a 4.0 V6. Is the connection on the left firewall the inlet or outlet? Also where do each one run to. Thanks, Steve.

 

HeaterCore connections can be hosed up either way;
actually good to reverse HeaterCore connections\flow when Coolant is renewed, every 33kMiles\4Years.
One 5/8"ID HeaterHose runs to ThermoStatHousing; other 5/8" HeaterHose runs thru HeaterControlValve to Pump.
Click links below for more info on CoolantSystem for this 2001~2003 era Ranger\Sport\SportTrac V6~4.0L~SOHC:
https://2001fordexplorersporttrac.fa...Engine_Coolant
https://2001fordexplorersporttrac.fa...an+Clutch+Pump
https://2001fordexplorersporttrac.fa...t_Radiator+Cap
https://2001fordexplorersporttrac.fa...ant_ThermoStat
https://2001fordexplorersporttrac.fa...nt_HeaterValve

 

+1 ^^^^

There is no IN or OUT on a heater core, in fact you should swap hoses around every 2 years or so to reverse the flow thru the heater core, it will help keep it cleaner and last longer

 

The left port of the heater core runs to the thermo housing, the right port runs to the heater valve then to the water pump with the arrow on the heater valve pointing back to the heater core. This is a new heater valve I put on, but, the old heater valve had the arrow pointing towards the water pump. I know I have the right heater valve because the auto parts store said it's the one listed for my truck. Which way should the arrow be pointing to the core or the water pump. Thanks for your help. Python.

 

Again doesn't matter which way hoses are connected at HeaterCore, just reverse them every time you Drain+Refill coolant.
Flow is TStatHousing to HeaterCore to ControlValve to Pump thru Engin & around again, so point arrow with flow;
though BallValves work equally well either way & doesn't really matter.
FYI, guys that work PartCounters are usually but not always correct;
they deal with hundreds of models\makes\years & make mistakes, so best to confirm part# & fit yourself.

 

Thanks DILLARD000, In other words what you're saying is the arrow from the heater valve should be pointing towards the water pump not the heater core. You also said the heater valve arrow can point in either direction and that wouldn't matter, is that correct? Python. I've noticed that it takes awhile for the heater to heat up, but, it did the same even when the arrow on the old heater valve pointed towards the water pump.

 

Yep correct on arrow direction; I'd orient Valve so to make a good sturdy VacLine connection.
My 2001 V6~4.0L~SOHC takes roughly 5min to warm up & get good heat in cab on cold winter mornings.

 

Thanks DILLARD000, I appreciate the info.