My Cadillac Deville is keep running hot and idk why. It's leaking oil and my transmission fluid is not staying in the car. What advice or steps I should take?

It maybe the seals are leaking. For a quick fix try adding a can of leak sealant that you can get at your local friendly auto parts place. I have also used DOT 3 brake fluid back in the old days. Just remember. This is just a quick fix at best.

Yo, Check where you put the oil, if you see like creamy shit under the oil filler cap that's a problem. Just change the thermostat to be safe, make sure the coolant is full, when this car runs hot the coolant goes to the overflow and then bubles out so your probably low on coolant maybe empt the radiator and refill with dexcool, make sure you cut it 50/50. I have a 2005 I love it, I hate it. don't overheat it you'll blow the heads (aluminum)then that's it for the engine. good luck

I have a 1999 Cadillac it will run hot sometime but if I drive fast it would not if I drive slow start run hot

By pass ur heater core hose thats wbat ive done 2 a couple of my cars & all i drive & own is cadillacs and ive had this problem more then ONCE changing radiators /water pumps/ even heads & head gasket to find out it was my heater core!these cars are bad about the ht cores 4 some reason. Good luck & hope it works 4 u ,i believe it will trust me..