bpjon65

Installed a new water temp sensor into the aluminum intake manifold. No tape or thread sealer was used. I did have a reason for doing this but don’t need to get into that. The temp gauge went to 240 in about 5 minutes. Put old one back in and worked fine. Aren’t all sensors the same? Just curious why this happened.

jim lockwood

All sensors are definitely NOT the same. Modern sensors aren't constructed to withstand the current our old cars' electrical systems pass through them. As a result, they self-heat which makes the gauge read higher than the actual temperature.

Read this thread for more detail:

why temp senders make gauges read high