R34 Series II lower radiator thermo switch thread size

[JarrettL]

Disclaimer: This isn't a topic specifically related to forced induction, though the vehicle it applies to will be boosted, so...

 

I recently purchased a Series II R34 GTR radiator from Koyorad to install in my ENR34 project. I'm building a motorsport-level (or near enough, anyway) harness for it, so the addition of a threaded boss on the radiator to use for a coolant pressure sensor was enticing. Especially since I was buying a radiator, anyway. I have a large M16x1.5 bolt that I've easily threaded into the hole, but it still has a little play at full engagement. Does anyone know what the true thread size of this hole is so that I can buy an adapter for a pressure sensor?

 

[Rusty Nuts]

If M16 is close, then possibly 3/8 BSP or BSPT. Or its simply a M16 tapered thread. Buy a set of thread gauges they are cheap and last a lifetime or two. My set belonged to my father.

 

Adapters you can get from

https://www.threadtoolsupply.com/thread-adapters.html

Edited March 1, 2021 by Rusty Nuts
additional information

[JarrettL]

I had the absurd idea of actually contacting the manufacturer through their "Contact Us" portion of their webpage and they insist that it's an M16x1.5 thread. I assume that once the o-ring on the bottom of the hex portion of the sensor its in that slight recess, combined with light torque would eliminate the play I'm feeling now.

 

Anyway, just updating this in case anyone searches this topic at some point in the future.