Toyota installed oil coolers on most 3vz & 5vz engines, but not all.  Before ordering an engine, you will need to know if you have an oil cooler or not (the water pump and gasket set will be different).  It is possible to check using the VIN number, but this can be difficult and is not guaranteed to be 100% accurate.  The best way to know if your engine has an oil cooler is to look at the thermostat housing area of the water pump.  On engines WITH an oil cooler there will be a metal nipple with a rubber coolant hose attached to it (side of water pump just behind the thermostat housing).  The oil cooler itself is mounted on the driver side of the engine near the back of the block, the cooler can be a little tricky to see with the engine still in the vehicle, but can usually be seen thru the driver side wheel well. 

 

_ 3VZ & 5VZ Oil Cooler

 

_ 3VZ & 5VZ Oil Cooler