I picked up modine Radiator to replace my cracked stock Radiator . Problem is there is a male extension on the bottom left that connects to bottom extension of water pump via hose . On the modine Radiator there is nothing there ! I purchased the correct / or so the box says Radiator for car everything else hooks up perfectly , is it possible to just cap off extension from water pump ??

 

Yes, you can cap that off. The hose that goes between the two, is a bypass hose when the car is not equipped with an oil cooler. If you have an oil cooler and are going to keep it, then you will need a radiator with that port on it.