Water pump noise means the bearing is going out. Replace it soon.

Two person job: With the hood up and one person standing to the side of the vehicle, have the other person put the car in gear while holding the brake firmly and with the parking brake engaged. Person in the driver's seat gives the engine a little throttle. Observe the engine for jumping or movement.

Check the engine for vacuum leaks and verify the proper ignition timing. A good quality fuel injector cleaner might also be a good idea.

Answered by rivermikerat (expert)
5,494 answers provided

Thanks, I was afraid you'd say that. The water pump looks like a pain to change! I'll check the other items also though I haven't noticed any performance or mileage changes.

Response from coptermech
1 question asked

See image.
2.4L 4-CYLINDER ENGINE -2003 Kia Optima SE
Page 1 of 2
ENGINE COOLANT PUMP
REMOVAL

Drain the coolant and disconnect the radiator outlet hose and engine coolant by-pass hose from the engine coolant pump.
Remove the drive belt and engine coolant pump pulley. Remove the timing belt covers and the timing belt tensioner.
Remove the engine coolant pump mounting bolts and then remove the alternator brace. Remove the engine coolant pump assembly from the cylinder block.

Install the timing belt tensioner and timing belt. Adjust the timing belt tension, and then install the timing belt covers.
Install the engine coolant pump pulley and drive belt, and then adjust the belt tension. Refill the coolant.
7. Run the engine and check for leaks.

Answered by rivermikerat (expert)
5,494 answers provided