FYI there is a difference between a "Coolant Temperature Sensor" (sends signal for emissions, gauge) and a "Coolant Temp Switch"

Auto-part guys typically get them confused or the part look up system refuses to acknowledge that both exist. 99% of everything obd1, some obd0, and newer has both of them.

Check numbers 16 and 17 in this image.


Boiling fluid sounds like: a HG, bad Tstat., air in the system etc.