2001 Lincoln LS is overheating have already change thermostat and coolant reserve tank! What else could be the problem someone please help

I have an LS that had the same problem. Because these cars do not have PCV valves, your bleeder may need to be replaced. They are great cars, and very high tech even for a 14 years old. Speaking of age, 14 might mean it's time to have the hoses and water pump inspected too. I have 205,000 miles on mine, and it's been great! The repairs are on par with any other luxury car, so staying ahead of the game and shopping around is very important. Also, if you have a V8, check eBay if there is a need to replace the ignition coils.

I had the same issues with my 2003 LS and had to replace everything including the radiator all the hose, thermostat. I was like a guessing game and it was costly due to my limited experience with cars.

You have an actuator that speeds up the hydrolic fan If it’s not working your auto will stay cool if your running up to speed but will over heat in stop and go traffic . Had same problem.

It's the heater control valve. I have an 01 ls that had the same issue. I changed the water pump, radiator , thermostat x2, Degas resivoir w/cap,made sure my blend doors were working properly, switched over to electric fan , and checked heater core andevery hose for blockage. Each part I changed I went through the bleeding process over and over again. The heater control valve was the last thing I replaced and it fixed my problem. Removing all air from the system is mandatory and it can be a long process.