No - you can re-use the original sensor as long as it is working OK.

I replaced the sensor as it was relatively inexpensive and it didn't make sense to me not to replace the sensor when I was in there already replacing the tank and cap. I don't think there is a right or wrong, it's more of a personal judgement call.

Hi,
thanks to 986 Ron for this thread and others like Pedros garage, i managed to change the coolant tank my self, it was PITA to work at the engine compartment.....
Did get the clamp plier tool, but it cracked on me the first try, so i managed to use needlenose pliers With a bit of luck...so a tip, don't buy cheap ebay tools and get a quality one instead.
Thanks to this forum and i'll hope none of you gonna work on the coolant reservoir in the future....;)

Dipstick depth is obviously critical. The pic above of the original unit makes it look like the depth is controlled by a boss, which is missing on the replacement. How did you make sure the dipstick was sitting in the same relative position at the end of the day?