The oil and coolant temperature gauges show the same temperature which is what you want
everything I read put out by ford says the oil temp should be 15 degrees above the coolant temp. if there is no difference then something isn't working as the coolant is suposed to be cooler than the oil so it can do its job and remove heat. I think you have an issue with that motor that you have missed or danced around. first thing I would do is check the overflow cap and see if it is still good, maybe throw a new one on if it is old for the heck of it. then I would do a test to see if you have combustion gasses in your coolant.
I have read, if you see a 10+ degree difference, you need to swap out the oil cooler, I've read the temperatures should be close to the same when the oil cooler is unclogged and functioning properly.
the factory spec is 15 degree seperation, over that then you start to watch it and/or start checking to see whats happening.
