Engine Oil Temperature Sensor

[Horntoad]

Merry Christmas everyone!

I am about to replace the engine oil cooler lines (with nylon covered rubber hose and -8 AN ends and fittings) and change the oil filter adapter gasket. Figure it is easier to do those two things at the same time. Anyway.

While I'm at that I'm considering adding an engine oil temperature sensor and gauge. I've got a couple questions.

1) what are the plugs on the oil pan side of the engine oil cooler adapter? Are those ports for temperature sensors, and if so what size and thread type; and why are there two; is one before the oil has gone through the cooler/radiator and the other after?

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2) what is the oil flow path in relation to the oil cooler/radiator and filter; does oil go from the pump to the filter first and then through the cooler/radiator or first through the cooler/radiator and then through the filter?

3) other than drilling a hole in the oil pan, what locations are my best options for installing an engine oil temperature sensor? I'm thinking about adding one along the -8 AN oil cooler lines, and I think I'd rather put the sensor at the oil filter adapter end of the hose as the temperature before the oil travels through the inlet cooler line should be closer to the the sump temperature, but it probably won't drop by that much, depending on ambient, outdoor temperature.

Thanks for reading and for any insight you can provide!

(The above are my main questions. The below is about trying to find the right temperature sensor adapter/fitting for my -8 AN oil cooler line. But, of course, if those plugs/ports on the side of the adapter can be used for a temperature sensor and it will fit between the adapter and the oil pan all this 1/8" NPT hose adapter/fitting stuff becomes a moot point.)

But, I'm having some trouble finding a fitting/adapter for the 3/8" NPT ports on the oil filter adapter (though I have found an adapter with a 1/8" NPT port that would work on the cooler/radiator end of the cooler lines). For reference I'm doing 20mm x 1.5 metric to -8 AN flare adapters and -8AN 90-degree swivel hose ends on the radiator end (nylon-braided rubber hose) and -8AN hose to 3/8" NPT straight swivel fittings on the oil filter adapter end. (Since purchasing these hose fittings I have noticed that Phenix has pretty good prices.) But I'm open to changing one of the ends on the oil filter adapter end (i.e. from a -8AN hose-3/8" NPT to a -8 AN hose to male or female AN) if I can find an appropriate adapter for a 1/8" NPT oil temperature sensor/probe. The only 3/8" NPT female to 3/8 NPT male with a 1/8" NPT port fitting that I have found is designed for a pressure sensor (the port is not recessed, standoff, or setback) and most (all) oil temperature sensors extend beyond the 1/8" NPT port threads and thus the probe would somewhat obstruct the flow of oil through the cooler line (I believe). I'm thinking maybe I can find, if not a similar 3/8" NPT female-to-male fitting but with a standoff, recessed port, maybe I can find a tee with 3/8" NPT female to 3/8 NPT male with a 3/8" NPT (male or female) to which I can fit a 3/8" NPT to 1/8" NPT reducer, something like this.

 

[df2x4]

For reference I'm doing 20mm x 1.5 metric to -8 AN flare adapters

Be aware that those Vibrant adapters may not actually be correct for this application. More discussion on that subject starting around halfway through page 2 of this thread:

https://www.gmt400.com/threads/how-to-install-an-oil-cooler-lines.30454/page-2

 

[tayto]

the 80s corvettes had an oil temp sensor in the side of the oil filter adapter FWIW. In the pan is probably a better average for the temp though....

 

[Supercharged111]

the 80s corvettes had an oil temp sensor in the side of the oil filter adapter FWIW. In the pan is probably a better average for the temp though....

That's where I put the oil temp sensor on my dually. Yes it's a 454, but the 350 has a hole there too.

 

[GoToGuy]

The GM engineers placed the oil temp sensor there monitor oil temp in the block. Their reasoning isn't based on trend analysis, or heat exchanger cooling rates.
It's there they did the work for you.
Actual rubber hose or engine/ motor oil approved hose? The cooler filter adapter used in other applications therefore more routing options.
AN is 37 degree. NPT in the filter boss with AN male. Are you using stand alone oil cooler or radiator exchanger?
At any industrial, agricultural supply hose shop you can order JIC 37 ° hoses, styled like AN, built for you with permanent type compression or AN repairable ends with appropriate hose.
I ordered the adapter for the oil cooler AN from Summit. Keeping it simple will last longer.

Good luck.

 

[Horntoad]

The GM engineers placed the oil temp sensor there monitor oil temp in the block. Their reasoning isn't based on trend analysis, or heat exchanger cooling rates.
It's there they did the work for you.
Actual rubber hose or engine/ motor oil approved hose? The cooler filter adapter used in other applications therefore more routing options.
AN is 37 degree. NPT in the filter boss with AN male. Are you using stand alone oil cooler or radiator exchanger?
At any industrial, agricultural supply hose shop you can order JIC 37 ° hoses, styled like AN, built for you with permanent type compression or AN repairable ends with appropriate hose.
I ordered the adapter for the oil cooler AN from Summit. Keeping it simple will last longer.

Good luck.

I did purchase engine-oil-compatible nylon-braided rubber hose (and I've edited my original post to add that point there for clarity). And I have the stock (RPO) KC4 engine oil cooler.

It's been a minute since I ordered the hose parts, and I may remember being aware of the difference between the M20x1.5 to -8AN flare adapters I ordered and the OEM fittings on the radiator end of the lines (though not knowing that the type was "JIC") but maybe being sick of searching and wishfully thinking it didn't matter .

Is a JIC the same as an AN flare fitting? And if so I just need something with an M20x1.5 JIC/AN flare fitting for the radiator ends of the line?

 

[Horntoad]

That's where I put the oil temp sensor on my dually. Yes it's a 454, but the 350 has a hole there too.

Do you happen to know the size and thread type for those ports on the small block engine oil cooler adapter? Are they 3/8" NPT like the engine oil cooler line ports?

 

[Piratehunter]

Whisler Industrial Supply in Colorado Springs can identify provide the hoses and fittings for you. they are real good for this.

Update. sorry, thought I read your location as Colorado, eyes not focused yet this morning. An industrial supply shop near you will be able to sort this out quickly if you take the housing, hoses, and cooler in to them. Good luck

 

[Schurkey]

Despite advertising at Summit and Jegs and other aftermarket sources, there is no such thing as "AN" fittings any more.

"AN" is obsolete and has been for decades.

"JIC" is similarly obsolete; but represents an "industrial-grade" version of what was an aerospace "AN" system. The pieces have the same flare angle, and the same thread sizes, but "JIC" was made to lower-cost standards.

Both "AN" and "JIC" have been replaced by different SAE designations.

 

[Horntoad]

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These are the ends of the OEM AC Delco engine oil cooler lines (12472277 and 12472278; one came with an o-ring [the outlet line for what it's worth] and one did not, but I'm not sure if that is the way they are supposed to be or if they both should have an o-ring). Is that a JIC? Or is it a metric o-ring port?

Am I correct in understanding that the engine oil cooler line end type at the radiator is different between 88-95 and 96-98 (and is that contributing to the confusion)? I have a (very late model-year 1995 Oct 16 build date) 1995 2DR 4WD 5.7L LS Tahoe.

Do I need metric o-ring port fittings on the radiator ends of my custom engine oil cooler lines (and is that in fact an M20x1.5 metric o-ring port)? Or would it work with liberally applied thread seal teflon/PTFE tape and the 20mm x 1.5 metric to -8 AN flare adapters that I already purchased (as I wishfully thought it might)?

(So far I've found several of, while the appropriate type what I believe to be, incompatibly-sized M16x1.5 o-ring port to -6AN flare adapters. When I search o-ring port adapter some have the o-ring on the nipple end [like the OEM photo and M16x1.5 o-ring port to -6AN adapter example I included in the previous sentence] and some have the o-ring at the collar/neck. So, I'm not sure I've got the terminology "metric o-ring port" entirely correct, but again do I really need o-ring flange?)

As I've thought about this more I remember why I felt I could go with the 20mm x 1.5 metric to -8 AN flare adapters despite the OEM o-ring flange style. The OEM style engine oil cooler lines have metal ends and a rubber center section. What follows is my logic and purely conjecture and not all terminology may be technically correct. In order to form a seal with the metal tube at the radiator end of the line GM chose an o-ring and compression flange on the metal tube itself. That may have been easier and/or more cost effective than trying to form a seal between the metal tube end and the M20x1.5 nut. And furthermore this design forms a type of swivel end; directly threading the metal tube end would have required spinning the whole cooler line to thread the end into the female port on the radiator; impractical. So, whereas I don't need to seal a separate internal metal tube to the radiator port (as in the OEM design), I felt I could use the 20mm x 1.5 metric to -8 AN flare and seal the threads instead (my entire hose assembly is listed in the original post; and, on this logic, I'm going leaning towards putting the custom hoses together and installing them).