2005 Lincoln Ls overheating problem

check your reservoir bottle if it has the slightest leak it will overheat

You have to use parts from a Ford dealership. If not you will continue to have problems. In this car aftermarket (OEM) cooling system parts are not up to the same quality as the factory parts. I know, they are much cheaper & many have a lifetime warranty (free parts replacement only) but, how much will it cost if you have to replace one lifetime warranty part or another every month or so. Some of these aftermarket parts don't work properly to start with. Think about your time, if you do the repairs yourself, coolant, towing, not to mention countless trips to the parts store. Then after all of that, you spend a lot more money to buy the factory cooling system parts from the Ford dealership that will last for about 100K miles. It cost me about $700 in dealership parts but I can drive my Lincoln LS anywhere with confidence!