The replacement radiator for my 1993 K3500 6.5 TD has two options, with or without "engine oil cooler". They are basically the same except the one with the engine oil cooler has 4 fitting, 2 on each side, one set trans oil and one set for engine oil cooling.

I would like to get the radiator with the engine oil cooler and run the engine oil to the radiator first and then to an external cooler to get more cooling. Which fittings on the block are the "out" and "in"?

On the radiator should the engine oil flow go from the top to bottom OR bottom to top?

I am also installing the 97 and up cooling upgrades with a high flow WP.

Thanks for the help.

I think the line that goes farthest back on the engine is the out line (right fitting on oil cooler) and the other is the return (left fitting). I also think your line in is up high and the return is the lower on the radiator.