* Water Pump: This is the most common reason. A failing water pump can't circulate coolant effectively, leading to overheating. Even if it seems to spin, the impeller might be worn or damaged, preventing sufficient flow.
* Air Pockets in the Cooling System: Air trapped in the system prevents proper coolant circulation. Make sure the system was properly bled after the radiator and thermostat replacement. There are often specific procedures for this, depending on the vehicle. Insufficient bleeding is a very common cause of overheating after coolant system work.
* Faulty Radiator Cap: A bad radiator cap won't maintain proper system pressure, which is crucial for preventing boiling.
* Head Gasket Failure: A blown head gasket allows combustion gases to enter the cooling system, causing overheating and potentially pressure buildup. This is a more serious issue and often presents with other symptoms like white smoke from the exhaust or milky oil.
* Clogged Radiator: Though you replaced it, there's a small chance the new radiator is clogged internally (rare but possible). Less likely given the recent replacement but worth a thought if other issues are ruled out.
* Fan Clutch/Electric Cooling Fan: The fan may not be engaging properly or might be faulty. The cooling fan is crucial for cooling at low speeds or when idling.
* Thermostat Housing: While you replaced the thermostat, there might be a problem with the housing itself – cracks or leaks.
* Coolant Leaks: Inspect all hoses, connections, and the water pump for leaks. A small leak can lead to significant overheating over time.
* Low Coolant Level: Double-check that the coolant level is correct, even after filling it. If it's dropping, there's a leak somewhere.
Troubleshooting Steps:
1. Check for leaks: Carefully inspect all hoses, clamps, the radiator, and the water pump for any leaks, even small ones.
2. Bleed the cooling system: Follow the proper procedure for bleeding the cooling system for your specific Intrepid model. This is often overlooked.
3. Check the radiator cap: Ensure the radiator cap is functioning correctly and holds the correct pressure.
4. Test the water pump: Listen for unusual noises, and if possible, visually inspect the impeller to ensure it's spinning and not damaged. A mechanic can typically diagnose this easily.
5. Check the cooling fan: Ensure the fan engages when the engine is hot. It might need replacement or the fan clutch could be faulty.
6. Check the thermostat housing: Look for cracks or leaks.
7. Inspect the coolant for signs of contamination: Milky or brown coolant can indicate a head gasket problem.
8. Check coolant level again: Even after bleeding, a persistent drop suggests a leak.
If you're not comfortable performing these checks yourself, take your Intrepid to a qualified mechanic for diagnosis and repair. Overheating can cause serious engine damage.
