Since my vacuum actuator thing on my thermowax is broken I had the idea to use it as a location for an aftermarket water temp sensor. It looks like the threads are close to 3/8 npt because the thermowax threads into my fitting, but when trying to thread the npt fitting into the throttle body it doesn't want to fit. Upon closer inspection the threads ARE different.


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Does anyone know the pitch of this? Maybe bpst or something? I tried searching but couldn't find it mentioned anywhere.

 

Done a little bit of research on fitting a npt coolant temp sensor to replace the stock one and it is bpt or bpst.

 

Are you sure the threads in the thermowax are clean? I'm fairly certain it was 3/8" NPT, since the plug I used fit perfectly.

It's possible I was wrong about the thread on the plug though, it was leftover from some other part I'd long since forgotten purchasing.

 

Just looked up the thread charts and a 3/8 npt is 18 threads 60 degree per inch 60 degree thread angle and a bpst is 19 threads per inch 55 degree thread angle... so close, no wonder why there’s confusion.

I might have a throttle body laying around I can try to remove the thermo wax and try threading a 3/8 npt fitting into.