2003 F150 4.2 NO HEAT , AC STAYING ON, THE OTHER DAY THE OVERHEATING GAUGE WENT UP AND HAD LOW ENGINE POWER ,TEMP LEVELED OUT STILL NO HEAT, CHANGED THE THERMOSTAT W/NEW AND FLUSHED OUT HEATER CORE...STILL THE SAME. HEATER LINES, ONE HOT, ONE COLD. AC RUNNING CONSTANTLY
Ford Q&AAsk Your Question
2003 Ford F-150 Question: 2003 F150 4.2 NO HEAt...see more below
Answer #1gmc4me January 28, 2012, 13:08Journeyman
Since you have two problems it seems that your water pump propeller may have come apart but you may have heard some noise under hood. Does the vehicle overheat everytime you drive it?
Reply03fordf150, January 28, 2012, 13:22Rookie
No, it does not overheat all the time. Test running now...step on gas struggles to go and makes engine/knocking noise.
Replygmc4me, January 28, 2012, 22:40Journeyman
Im not sure about the overheating problem but the noise from the engine may be due to it overheating. The heater hoses being the way you say leads me to believ that the heater core may be blocked. Find out which way the coolant flows through the heater core which would be the hot hose as you said earlier and hook up a garden hose to the outlet of heater core. This will back flush the heater core. Watch for sludge and debris as the hose runs to verify if this was your problem. The water should flow at a decent rate.