Dodge Ram 1500 Overheating or Running Too Hot

Dodge Ram 1500 Running Too Hot or Overheating 2001 2002 2003 2004 2005 2006 2007 2008

Dodge Ram 1500 overheating or running too hot refers to when the vehicle’s temperature gauge reads high or when the coolant warning lamp illuminates.

There can be several possible causes for a Dodge Ram 1500 to overheat or run too hot. Follow this troubleshooting guide to identify possible causes and solutions needed to correct the problem.


Dodge Ram 1500 overheating or running too hot 2001 2002 2003 2004 2005 2006

  1. Pulling a trailer, climbing a steep hill or moving slowly in traffic with very high ambient outside temperatures with the A/C on can cause the vehicle to run hot. The condition may be temporary and my not require repair. Turn off the A/C and observe the temperature gauge. If the gauge doesn’t return to normal operating temperature determine the cause of overheating.
  2. Is the vehicle’s temperature gauge defective? Test gauge, refer to “Electrical/Instrument Cluster” section in the download repair manual for testing procedures.
  3. Low coolant in reserve, low coolant in radiator or overflow tank. Fill with coolant if necessary. Check coolant system for leaks.
  4. Radiator pressure cap not correctly tightened. Tighten cap to fix. If the radiator cap is loose the coolant’s boiling point will be lowered.
  5. Defective radiator cap seals. Remove the radiator cap and inspect the seal’s condition, replace if needed. Also, check radiator filler neck for cracks or other damage, replace radiator if needed.
  6. Coolant and water mixture ratio incorrect. Check coolant, refer to the “Lubrication And Maintenance” section in the download repair manual for fluid types and mixing quantities.
  7. Coolant is not flowing through coolant system. Make sure coolant if flowing at the radiator neck with some coolant removed, engine warmed and thermostat open. You should visually see coolant flowing through radiator. If coolant isn’t flowing determine area of obstruction and fix.
  8. Radiator or air conditioning fins excessively dirty or clogged. Remove dirt, debris and insects.
  9. Radiator core is corroded and clogged. Replace the radiator with a new unit or have it re-cored.
  10. Aftermarket air conditioning installed without proper radiator. Install a radiator compatible to aftermarket air conditioner.
  11. Ignition or fuel system issues. Refer to the “Fuel System/Electrical Diagnose” section in the download repair manual.
  12. Dragging brakes. Refer to the “Brakes/Diagnosis And Testing” Section in the download repair manual.
  13. Bug screen restricting air flow to radiator. Remove bug screen.
  14. Thermostat malfunctioning or sticking. Check or test thermostat and replace if needed.
  15. Viscous fan drive malfunctioning. Check fan drive operation and replace if needed. Refer to “Removal And Installation” procedures in download repair manual.
  16. Vehicle’s cylinder head gasket leaking. Check for cylinder head gasket leakage.
  17. Vehicle’s heater core leaking. Check heater core for leaks and replace if needed. Refer to download repair manual for checking procedures.

Always use a downloadable factory service manual when performing service or repairs to the Dodge Ram’s cooling system.


  1. I need instructions on how to repair cooling system for a 2005 dodge 5.9 diesel cummins, this information is for gasoline engines.

  2. Are there diagram pictures of a dodge ram 1500 v8 5.9 lter engine cooling system in download repair manual?

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