* Power Steering Pump: A whining noise from the power steering pump is common, especially when the engine is idling or under light load (like when you release the gas). It often gets worse as the pump ages or the fluid level is low. Check the power steering fluid level and look for leaks.
* Water Pump: A failing water pump can sometimes produce a high-pitched whine, particularly under light load. This is less common than a power steering pump whine but worth considering. Listen carefully to pinpoint the location of the sound.
* Exhaust Manifold Leak: While less likely to sound like a *whine*, a leak in the exhaust manifold can create a high-pitched whistling or whining sound, especially when the engine is under less load. Check the manifold for cracks or loose bolts.
* Transmission Issues: Although less probable, a problem within the transmission itself (bearings, for example) could contribute to a whine that's more noticeable when the engine is under less stress. This is harder to diagnose without professional help.
* Belt Tensioner: Even with the idler pulley changed, the belt tensioner itself could be failing. A worn or failing tensioner might create a whining noise under varying engine loads.
* Differential Issues: While less likely to be directly linked to releasing the gas, a whining sound from the differential can sometimes be heard and might be more noticeable at certain speeds. This is more likely to be a constant whine rather than one specifically linked to releasing the gas.
Troubleshooting Steps:
1. Listen Carefully: Try to pinpoint the location of the whine. Is it coming from the front of the engine (power steering, water pump, belt tensioner), the rear (transmission, differential), or somewhere else?
2. Check Fluid Levels: Inspect the power steering fluid, coolant, and transmission fluid levels. Low fluid can exacerbate noises.
3. Inspect Belts and Hoses: Look for cracks, wear, or slippage in the serpentine belt and all hoses.
4. Listen at Different Engine Speeds: Does the whine change with engine RPM? Does it only happen when letting off the gas, or is it present at other times?
5. Professional Inspection: If you can't pinpoint the source, take your Jeep to a mechanic. They have the tools and experience to diagnose the issue accurately.
A whining noise is often indicative of a component that's wearing out or has low lubrication. Don't ignore it; continued operation could lead to more serious damage.
