Oil/Coolant Temp Sensor


I'm trying to plumb the oil temp sensor of a SPF into my oil line. The coolant and oil temp sensors are mechanical. Looks like the coolant temp sensor will plug into a boss on the intake manifold so that should be solved (yet to try it). I was planning on putting in a -12AN T fitting into the oil line and bought this Fragola Performance Fitting that screws into the -12AN. Supposedly the other side of it accepts an oil temp sensor but as the photo shows, it's too small. Honestly looks more like a female -6AN to female -12AN fitting.

So, what's the best way to plumb this mechanical fitting into an oil line?


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Terry Oxandale

Skinny Man
It appears from the photo that you've got a bushing (adapter) threaded onto the sensor's NPT bushing (looks like both of them are aluminum?). If this is true, can the larger bushing be removed to utilized the smaller bushing (I know, that sounds too obvious, but just going by the photo).

There are probably a million ways to do this, but I would look to see 1) will the sensor fit into the -12 male hole that the cap screws onto, and 2) then, if it will slip into the male end, I'd tap the cap with the proper NPT tap at a proper depth, and then screw the sensor into the cap as it appears the cap was designed for.

Only a comment, but I've always looked for a location that has oil flowing directly around the sensor. Being all of this is brass and aluminum, I'm sure the temperature measurement is pretty close to the actual oil temperature, even if the sensor bulb is a close fit to the male fitting ID, and without oil directly flowing past it (kind of dead-ended in the tee). Perhaps I'm being a little to anal about this.
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Howard Jones

I like these. It's a AN10 if you want an AN12 then search the summit site for the same product family.

Allstar Performance Inline Oil Temperature Tees ALL90040 - Free Shipping on Orders Over $99 at Summit Racing

Put it in the line returning from the oil cooler. This is the oil that is being delivered to the bearings. Other wise put in a bung welded on the side of the oil pan. Oil galley ports on the block itself, unless they are in the same part of the casting that the oil filter is located on, are best used for oil pressure senders that don't have a temp probe sticking out in the oil galley. I have always wondered how much that probe was restricting oil flow. In any case I don't think there is enough volume of oil around the probe in those small galley way's to get a good temp reading.

That's my opinion. It's worth what it cost.


Howard: Thanks! That's exactly what I was looking for. The temp probe bottoms out in the Fragola part I noted above before the threads have any chance to engage. I think this is a much cleaner solution.


so it looks like the temp sensor fitting is a 3/8" NPT. The Allstar inline T is a 1/2" NPT so I'll be trying a 3/8" female NPT to 1/2" male NPT reducer. Can't believe a stupid sensor is consuming so much of my time to figure it out....:furious: