My mom's Lincoln LS V8 tends to overheat in any sort of stop/go traffic when it's hot outside. This has been happening since last summer but when the car gets moving or onto the highway, it comes back down to normal temperature. Luckily, she hasn't blown a headgasket or cracked the block yet.
The thing is, the fan kicks in at idle, and it seems a lot of people blame the hydraulic fan unit (which was replaced with an electric unit in 03), but the fan does kick in when sitting.
Also, from doing some quick google searches, it seems to happen to A LOT of LS owners, and no one really knows the common culprit (temp sensor, thermostat, air in the lines, or the fan unit) are all listed as a possibility. The fan unit is about $400 so we don't want to throw that kind of money at something if it's not going to fix it. Also, the V6 and V8 have the same radiator/fan apparently.
Looking for some collective help here. Thanks in advance.