Whining noise when I accelerate but only after I've driven the car for 20 minutes?

It seems to be a well known issue

https://www.google.com/search?q=2005+Jeep+Liberty+Whining+Noise+From+Transmission

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Hello Kim,

What type of vehicle are we discussing here? Engine? 2 WD? Transmission?

Is the whining noise present at idle?

Is your vehicle air conditioned?

I need some details to provide assistance.

Open the hood. Listen for where the noise is coming from. Fix the thing that is making the noise.

remove the belt and start the engine ..IF THE NOISE disappear it might be idler bearings that driven by belt but if the noise still there check the pcv valve..

The fuel pressure regulator & spyder assy, most likely is bad

Don't think that is your noise though

Check trans fluid,may be pump noise

I am having the same issue. Would love to know what resolved it for you?

it is not how many miles but the type of driving.

here is a OBD2 drive cycle test.

Generic OBD II "Drive Cycle" Most OBD II ("On-Board Diagnostics II") diagnostic monitors will run at some time during normal operation of the vehicle.
However, to satisy all of the different Trip enable criteria and run all of the OBD II diagnostic monitors, the vehicle must be driven under a variety of conditions. The following drive cycle will (theoretically) allow all monitors to run on (??) vehicle. (Note: Drive cycle specifics vary by vehicle!)

1. Ensure that the fuel tank is between 1/4 and 3/4 full.
2. Start cold (below 86°F /30°C) and warm up until engine coolant temperature is at least 160° F (typically requires at least one minute; up to 3 minutes).
3. Accelerate to 40-55 MPH at 25% throttle and maintain speed for five minutes.
4. Decelerate without using the brake (coast down) to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.
5. Restart and accelerate to 40-55 MPH at 25% throttle and maintain speed for two minutes.
6. Decelerate with using the brake [or the clutch!] by coasting down to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.

check all vacuum switches for leaks

hi more than likley to be the alternator remove your fan belt start engine see if noise disapears yates210456