1969 cadillac hearse and it is running really warm you replaced the water pump and the thermostat what else could it be?

Answer I had a similar experience with my 68 Fleetwood Series 75 Limo. The problem was a plugged radiator. Cadillac uses a 4-row radiator for these heavy duty vehicles just to keep them from overheating.

Before I replaced the radiator, I would make sure the lower radiator hose is not weak. A weak lower hose can "suck closed" starving the water pump for water and resulting in over heating. Make sure the lower hose has a spring in it.

This spring is there to prevent the hose from getting sucked closed under normal conditions. There is a powerful suction created by the water pump and can collapse the lower hose without the spring Baring problems with the hoses (and you have replaced other possible causes), I would suspect the radiator is getting old and plugged up. I did not have any success with radiator cleaning as it was so old and weak, it had to be replaced.

Overheating is a thing of the past now.