2002 montero sport losing coolant but can't find the leak. No fluid on the ground. timing belt and water pump changed a year ago.

First is it really coolant Put a piece of cardboard down where you see the drip check before you start the car in the AM Color/Feel/Smell this will tell you if Antifreeze/Water from Exhaust start up/ or Oil like power steering etc. Didn't indicate if you've been losing antifreeze? Check all fluids you could have a Windshield wiper fluid leak too.
Hope I helped
Mike

it will be leaking oil onto the belt
it should be changed with every belt change along with all seals and idler pulleys
when in doubt ot oil residue in the housing, change it out

3 ways of loosing the coolant/water search for leak -hole in radiator,hoses at connections or damaged,water pump,heater core and hoses //blown head gasket coolant being burnt will show white smoke out tail pipe ,oil will show milky cocoa color ---//transmission oil cooler lines have internal damage in radiator and transmission has fluid draining

can you see the fluid circulate? with the cap of(radiator cap) see if the fluid moves around.
does it overheats? give me more info

I would check all hose clamps,tighten to make sure,check for signs of antifreeze.Crawl under and look and check for coolant.Check floor board for wetness.Is there any fluid coming from tail pipe?

It's under the timing cover on the front of the engine. I have pasted autozone.com instructions to replace the water pump below.

3.0L & 3.5L Engines

1. Before servicing the vehicle, refer to the Precautions section.
2. If necessary, properly release the fuel pressure.
3. Drain the cooling system.
4. Remove or disconnect the following:
   
   Negative battery cable
   

CAUTION Wait at least 90 seconds after the negative battery cable is disconnected to prevent possible deployment of the air bag.

Upper radiator shroud Accessory belts Air conditioning compressor tensioner pulley, if equipped Cooling fan and clutch assembly and the water pump pulley Thermostat and housing on 3.0L, 3.5L engines Water outlet, gasket and houses Radiator hoses from the water pump Crankshaft pulley(s) Timing belt covers. If the same timing belt will be reused, mark the direction of the timing belt's rotation, for installation in the same direction. Be sure the engine is positioned so the No. 1 cylinder is at the TDC of its compression stroke and the sprockets timing marks are aligned with the engine's timing mark indicators. Timing belt Water pump bolts are different lengths, note their positions before removing. Water pump from the block Water pipe connection and O-ring

To install:

1. Clean and dry the mating surfaces of the block and water pump
2. Install or connect the following:
   
   New O-ring on the water pipe connection, wet the new O-ring with water to aid in installation Water pump, with a new gasket, Torque the bolts to 17 ft. lbs. (23 Nm) on 3.0L and 3.5L engines Alternator bracket bolt to 17 ft. lbs. (23 Nm) Timing belt(s) and covers Crankshaft pulley(s) Thermostat and housing on 3.0L, 3.5L engines. Torque the bolts to 12-14 ft. lbs. (17-20 Nm). Radiator hose to the water pump Water outlet, new gasket and houses. Torque the bolts to 12-14 ft. lbs. (17-20 Nm). Water pump pulley Cooling fan and clutch assembly Air conditioning compressor tensioner pulley, if equipped Accessory belts Upper radiator shroud Thermostat and housing on 3.0L, 3.5L engines Negative battery cable
   
3. Refill the radiator with coolant. This cooling system has a self-bleeding thermostat, so system bleeding is not required.
4. Run the vehicle until the thermostat opens and fill the overflow tank. Check for leaks.
5. Once the vehicle has cooled, recheck the coolant level.

if it continues to do this while you drive, it is a sign of water/coolant in the exhaust due to a cracked head, block or most likely headgasket going out. Deal with this immediately before you need a whole new motor...

make sure your time is right

1, check fan drive belt tension. 2,radiator cap 3,thermstat operation 4.coolant hoses for leaks 5, heater internal leaks 6,fan clutch 7,a/c fan 8,shroud around fan 9.service radiator 10,water pump for leacks

hi there a couple of suggestions for you
there could be a leak in a hose?
or your water pump might be leaking?
also if you are using the heater it will also take your water .
also check if there is any holes or leaks from the radiator.