Q: Heater is not working. Replaced thermostat. Both hoses at firewall are cold. Maybe replace core? 2000 Ford F-250 5.4L

asked by on

2000 F-250 5.4L Heater is not working. Replaced thermostat. Both hoses at firewall are cold. Replace heater core? Controls are working. Engine temp is normal. Blows cold air only.

My car has 185000 miles.
My car has an automatic transmission.

Hi - most likely, either the heater control valve is not functioning properly, or the heater core itself is clogged enough to restrict flow. I would recommend a heater inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Heater is not working. Replaced thermostat. Both hoses at firewall are cold. Maybe replace core? 2000 Ford F-250 5.4L

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Heater not working properly, has oil leak.

It sounds like the problem could be with the blower motor resistor. If you only have one speed that the motor works on or the blower motor stops working all together you may need to have this replaced. A technician...

Q: Can I remove the fan clutch and put 1 or 2 fans with a thermostat to cool the engine?

Hi, thanks for writing in. The problem with using electric fans is the amount of air flow that the fans produce. It would not be an answer that could be answered without knowing exactly what the fans air flow is...

Q: Heater is blowing cold air 1999 Hyundai Elantra

Hi there. The blend door actuator is located toward the bottom of the HVAC box. It may be difficult to access, let alone replace. It looks like it may be located on the driver side of the box. One way...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...