* Belt itself: Even a new belt can squeak if it's not properly seated or if it's the wrong type. Check for cracks, glazing, or fraying on the belt. Try slightly tightening the belt (within manufacturer specifications, check your owner's manual), but be careful not to overtighten. A new belt might be the solution.
* Idler pulley: You've replaced the tensioner, but there might be other idler pulleys on your engine that guide the belt. These can wear out and squeak. Inspect them closely for wear, roughness, or bearing noise.
* Harmonic balancer (crankshaft pulley): This pulley can develop cracks or its rubber damping material can degrade, leading to noise. It's a more significant repair. You might hear a wobble or feel vibration along with the noise.
* A/C compressor: The clutch in the compressor is a frequent source of noise. Even if it appears to work correctly, it may still squeak.
* Something caught in the belt: A small stone or piece of debris could be lodged in the belt or between the belt and a pulley. Carefully inspect the area.
* Improper belt routing: Double-check that the belt is routed correctly over all the pulleys according to your vehicle's specifications. A misrouted belt can cause excessive wear and squealing.
Troubleshooting Steps:
1. Visual Inspection: Carefully examine *every* pulley and the belt itself for any signs of damage, wear, or debris. Use a flashlight and potentially a mirror to get a good view.
2. Listen Carefully: Try to pinpoint the exact location of the noise. Does it change with engine RPM? This helps narrow down the culprit.
3. Belt Dressing: As a temporary test (not a long-term solution), apply a belt dressing to the belt to see if the noise subsides. If it does, it suggests a slipping belt or dry belt as the problem, but only replace with a new belt.
4. Professional Inspection: If you can't identify the source after thorough inspection, take your Windstar to a mechanic for diagnosis. They have specialized tools and experience to pinpoint the problem accurately.
Remember to always disconnect the battery negative terminal before working on the belt system to prevent accidental shorts or injury.
