Before you begin:
* Safety First: Allow the engine to cool completely before starting any work. The coolant is hot and under pressure when the engine is running.
* Gather Supplies: You'll need a new thermostat (the correct one for your engine!), new gasket(s), coolant (the correct type for your system), a large container to catch the coolant, wrenches (various sizes), possibly pliers, and rags.
* Protect Yourself: Wear safety glasses and gloves.
Steps (General Outline):
1. Drain Coolant: Locate the drain valve at the bottom of the radiator (or the engine block, depending on your specific van). Place your drain container underneath and carefully open the valve to drain the coolant. This can take some time.
2. Locate the Thermostat Housing: The thermostat housing is usually located on the engine block, near the top of the engine. It might be on the passenger side or the driver's side, depending on the engine. Consult your repair manual for the exact location.
3. Remove the Thermostat Housing: This usually involves removing several bolts or clamps that secure the housing to the engine. Be careful not to drop any small parts into the engine. Note how things are assembled; take pictures if necessary.
4. Remove the Old Thermostat: Once the housing is removed, the old thermostat will be visible. Carefully remove it, noting the orientation of the gasket. The gasket is likely to be damaged and will need to be replaced.
5. Clean the Housing: Clean the thermostat housing and its mating surface on the engine block thoroughly. Any debris or old gasket material can prevent a proper seal.
6. Install the New Thermostat: Install the new thermostat and its new gasket into the housing, ensuring it's oriented correctly. Consult your repair manual for the correct orientation if necessary (the direction the spring points, etc.).
7. Reinstall the Thermostat Housing: Carefully reinstall the thermostat housing, making sure all bolts or clamps are tightened to the correct torque specification (found in your repair manual).
8. Refill Coolant: Carefully add the correct type and amount of coolant to the radiator. Consult your owner's manual for the correct coolant type and mixture ratio (often a 50/50 mix of coolant and distilled water).
9. Bleed the Air: After refilling, run the engine for a few minutes to allow the coolant to circulate. Check for air bubbles in the system and bleed them out as necessary. There is often a bleed valve on the top of the engine or radiator. Your repair manual will detail this process.
10. Check for Leaks: Inspect all connections for leaks after running the engine for a short while.
Important Considerations:
* Repair Manual: A repair manual specific to your 1994 Dodge Ram Van B250 and its engine is crucial. It will provide detailed diagrams, torque specifications, and procedures specific to your vehicle.
* Engine Type: The location and specifics of the thermostat housing will vary slightly based on whether you have a 3.9L, 5.2L, or 5.9L engine.
* Coolant Type: Use the correct type of coolant recommended for your vehicle.
This is a simplified overview. Incorrectly performing this procedure could lead to engine damage. If you are not comfortable with this task, consult a qualified mechanic. The cost of professional repair is likely less than the cost of engine damage from a botched DIY thermostat replacement.
