I was a bit mystified. I was thinking the same thing... could it be a coolant level or maybe a pressure sensor? Looking at some diagrams and photos on the web, the normal configuration is a plug in that port, and I couldn't find any photos with the sensor.volvolugnut wrote: ↑24 Feb 2023, 16:34 I do not remember ever seeing a sensor in that location. Perhaps it is a coolant LEVEL sensor.
volvolugnut
But, mystery solved. It's a temperature sensor for an electric fan switch sensor. I don't think used on 240s, but 700/900 models did. There was collision repair in 1999 including the radiator. My bet is the shop sourced one off a later series.
https://www.ipdusa.com/products/7261/Ra ... 894-112973

BTW, the coolant was very clean. I was expecting some floating rust but nothing visible.






