Using old coolant temp sensor on passenger side head
I'm trying to reuse as many of my old dashboard gauges as possible, one of them being the water temp gauge. The old mechanical temp probe is mounted right next to the coolant hose neck on the Vortec Edelbrock Performer intake manifold - basically the old Gen I SBC style. I'd like to use this temp sensor on the passenger side of the LS1 241 heads.
I need a brass adapter that is M12 x1.5 male to NPT (size???) female. I'm pretty sure the LS1 hole thread size is M12 x 1.5 but I don't know the size of the other female end.
Does anyone know which adapter I need?
I'm guessing something like this but 1/8 NPT just doesn't sound right.
http://www.bodykits4me.com/product/6...ter_2277_.html
Last edited by RYU; Aug 3, 2009 at 07:53 AM. Reason: typo
Easiest way is to measure the threads on the existing sensor. Chances are it is not 1/8 but either 3/8 or 1/2 NPT. You are not going to find an adaptor for that since the M12 hole is too small.
Your options are to put 3 or 4 adaptors together, at which point the temp sensor will be so far out of the head it won't be accurate, or drill and tap the head to be 3/8 NPT (commonly done on here), or build your own adaptor to put the temp sensor in the block heater plug, or add a radiator hose splice with the proper size bung.
All of these options can be found if you search.
Easiest way is to measure the threads on the existing sensor. Chances are it is not 1/8 but either 3/8 or 1/2 NPT. You are not going to find an adaptor for that since the M12 hole is too small.
Your options are to put 3 or 4 adaptors together, at which point the temp sensor will be so far out of the head it won't be accurate, or drill and tap the head to be 3/8 NPT (commonly done on here), or build your own adaptor to put the temp sensor in the block heater plug, or add a radiator hose splice with the proper size bung.
All of these options can be found if you search.
I didn't want to daisy chain so many adapters together either. Was hoping there was an adapter already made. Something like the pic below.

The more I search, I think the best way is to convert to all digital gauges. Still hoping I won't have to though but I know the speedo has got to go digital for sure.
https://ls1tech.com/forums/conversio...ll-them-2.html
Looks like I won't find that adapter afterall but I may be able to cut and retap the fitting...
i would bet it could be made to fit into the block heater if you wanted to go through that much effort. This thread has a pic of how I did my Datsun sensor.
https://ls1tech.com/forums/conversio...r-adapter.html
Keeping the interior as stock as possible was a goal of mine.
I wanted to stay stock on my 66 Nova but after looking at their dashes it was too easy to just use it. Speed input, fuel level, tach, oil, water temp, engine service light (for the CPU controlled engines). It was easy install and looks great. Went witht the green instead of the blue for the softer look.
http://www.dakotadigital.com/index.c...rod/prd181.htm
I also got there shift indictor kit.
Thing is flawless.
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As mentioned in this pdf S&P has an aluminum adapter to go from the 12mm to 3/8 NPT - no drilling or tapping required. I just called to confirm and order it. I can't really picture how it's going to work since I still think the 12mm hole is too small to fit the thermometer probe into but we'll see in a few days. I'm hopeful this will solve the problem.
http://www.hotrodlane.cc/08%20catalog/Page%20140.pdf
i would bet it could be made to fit into the block heater if you wanted to go through that much effort. This thread has a pic of how I did my Datsun sensor.
https://ls1tech.com/forums/conversio...r-adapter.html
Keeping the interior as stock as possible was a goal of mine.
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