1. Safety First:
* Never open the radiator cap when the engine is hot. You risk severe burns from scalding coolant. Let the engine cool completely before working on the cooling system.
2. Identify the Symptoms:
* How quickly is it overheating? A gradual increase suggests a slow leak or less efficient cooling. A sudden spike suggests a more serious problem.
* Is the overheating consistent, or intermittent? Intermittent overheating might point to a sensor or electrical issue.
* Are there any other symptoms? White smoke from the exhaust (head gasket), loss of coolant (leak), unusual noises (water pump), or overheating only under load (radiator, thermostat, water pump) provide valuable clues.
3. Systematic Troubleshooting:
* Check the Coolant Level: With the engine cold, carefully check the coolant level in the overflow reservoir and radiator (if accessible). Low coolant indicates a leak somewhere in the system. Top it off with the correct 50/50 mix of coolant and distilled water. Never use just water.
* Inspect Hoses and Clamps: Visually inspect all hoses for cracks, bulges, or leaks. Check the clamps to ensure they're tight. A failing hose will restrict coolant flow.
* Examine the Radiator: Look for leaks, damage, or debris blocking the fins. A clogged radiator reduces cooling efficiency. You might need to flush or replace it.
* Test the Thermostat: The thermostat regulates coolant flow. A faulty thermostat (stuck closed) prevents coolant from circulating properly. You can test it by placing it in a pot of boiling water to see if it opens at the correct temperature (usually around 195°F or 90°C – consult your repair manual for the specific temperature).
* Check the Water Pump: The water pump circulates coolant. A failing water pump will make a whining or gurgling noise and may cause poor circulation. Inspect for leaks around the pump.
* Inspect the Radiator Cap: A faulty radiator cap can prevent proper system pressure, leading to overheating. Replace it if it's damaged or if the pressure valve doesn't work correctly.
* Check the Fan Clutch (if applicable): This engages the radiator fan to help cool the engine. A malfunctioning fan clutch may not engage when needed. You might be able to test it manually (with caution) but often replacement is required. Some Probes had electric fans, check the fuse and wiring.
* Inspect the Fan (Electric): Check for operation and damage. Replace if necessary.
* Check the Cooling System Pressure: Using a pressure tester you can pressurize the system to check for leaks under pressure. This is a very important step.
* Consider the Head Gasket: If you're losing coolant, have white smoke from the exhaust, and have low compression in one or more cylinders, a blown head gasket is a serious possibility. This requires a much more involved repair.
* Bleeding the Cooling System: After any repairs, it's essential to bleed the air out of the cooling system to ensure proper circulation. Consult your repair manual for the correct procedure.
4. Seeking Professional Help:
If you're not comfortable performing these checks and repairs yourself, take your 1990 Ford Probe to a qualified mechanic. Overheating can lead to serious engine damage if not addressed promptly.
Important Note: A 1990 Ford Probe repair manual specific to your car's engine (2.2L or V6) is highly recommended. It will provide diagrams, torque specifications, and detailed procedures for all the components mentioned above. You can find these manuals online or at auto parts stores. Remember to always use the correct replacement parts.
