I learned on two occasions that if a vehicle has problems the first 10000 miles get a buy back. They were problems constantly after that. At the min get an extended Toyota Warranty.
There seems to be some evidence that on Toyotas not changing every 5 years eats the head gaskets. Some kind of reaction?
I change mine every 5 years. Better for everything.
Check for oil leaks around the timing cover on the 2003 Camry XLE V6 . Also check head gasket and coolant needs to be replaced. Also check the VTC oil cooler hose and make sure its metal.