I've found a few threads that are close to answering this question, but don't quite get there. I'm looking for the thread size of the temp sensor on the rear iron, below the oil filter
I know the oil pressure sender is 1/8" BSPT, but I've seen several people say the coolant sensor is ALSO 1/8" BSPT. This doesn't appear to be the case, as I have an adapter that will thread into one, but not the other.

Can anyone point me in the right direction? It appears to be a tapered thread like NPT, but smaller than 1/8"


Picture for reference

 

it depends on if that housing was made before 1988 or not.

 

The iron pictured is from a spare T2 iron I have sitting around. Not sure of the production year of that one
The motor in my car is an 88 motor, so i assume the irons are also made in 88

Just out of curiosity, what would the thread size be pre-88, and post-88?

 

Hello,

I think this is the part that goes in there right?. . At least it does on my 86 S4 N/A.. . . see if rock auto offers this same part for a turbo to be sure. I think this is a Standard Motor Products TS74

Measured diameter for the thread section on my calipers is dia. 7.89mm . . . Looks like a straight thread because it uses a copper gasket for sealing.

Looks fine thread M8. . . Just my guess.. . .find yourself a M8x1.0 or M8x.75 screw and try it out.

hope this helps.

 

One more thing. . .What I remember about this part is that on the car, it is near impossible to get in and out with the oil pressure sender in that other NPT hole.. . I had to remove that to replace the water temp sender easily.

 

Appreciate the insight! I will give that a shot.

 

if you search you should come up with it, its come up before

 

Witness marks indicate to me that its a metric thread that used a washer ("old style" in the above pic).