Koso slim water temp gauge install

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So what’s the consensus? 40mm or 38mm adapter? I’m reading people using both.
 
Looking to do this mod using the 40mm glowshift water sending hose attachment in the upper radiator hose. I’ve read this whole thread, and seem to have some conflicting info on fitment for the Koso temp sensor thread (1/8 BSPT) going into the adapter thread (1/8 NPT). Will this theoretically work if using pipe sealant (teflon) or am I asking for trouble? Thanks all
 
Looking to do this mod using the 40mm glowshift water sending hose attachment in the upper radiator hose. I’ve read this whole thread, and seem to have some conflicting info on fitment for the Koso temp sensor thread (1/8 BSPT) going into the adapter thread (1/8 NPT). Will this theoretically work if using pipe sealant (teflon) or am I asking for trouble? Thanks all
get an adaptor.. Nothing special.
 
Easier said than done. I can’t seem to find one that has the male side as 1/8 NPT. Most are opposite. The only adapter I found doesn’t work well with water temp as the hole for the sender isn’t big enough for accurate temp readings.
 
i had mine for over 5 yrs now and never had an issue. I will look into it and report back on the adaptor
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Had mine installed for almost 13 years and it still works great. The only thing I’ve had to do was reseal the sensor fitting to the adapter in the hose. I have put one of these gauges on every vehicle I’ve owned since then. I am about to put one in on my 99 F250 7.3.
 
Best ever investment, i always show it to my offroad buddies and recommend it.
Thanks for the fast reply, also I should also say its 2023 now :doh:
yah :-/ had a big issue with the car (the seller scammed me) so took some time to get part of my money back. (well better late than never only 3 years late hehe)

I got a FJ62 now :) and here are the pics of the installation.

WhatsApp Image 2025-03-23 at 12.26.41_4391d125.jpg
WhatsApp Image 2025-03-23 at 12.26.41_fbe1239d.jpg
 
I had to replace a leaking radiator so took the opportunity to install one of these Koso temp gauges. I installed it on the outflow water pipe (drilled and threaded). I’ve had this for a few years waiting for the ambition and opportunity to do this.

Easy install. I’m not going to keep the add a fuse I am using now and will do something better later. I notice that it reads within a couple of degrees warmer than the aluminum outflow pipe measured with an IR gun. It does run about 7-8 degrees cooler than the ECT measurement with the Toyocom. It appears accurate, but I guess the ECU measures ECT in a warmer area.

Around town with the AC on and temps above 100ºF ambient, the Koso reads 183-190º. It is funny to watch the heat soak inch it up in stop-and-go traffic. I’m thinking I’ll add 5º to the Koso reading to average out the overall system.
 

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