The plug located below and to the right of the Thermostat housing. Any idea what the thread size is?
I bought a temp gauge and figured it'd be easy to toss the sending unit in the hole with a bushing. No such luck, that plug is some bastard size. Closest I could find was for a 1/2" Flare fitting.

I'm pretty sure that TomR and some others have used that location for their temp sending unit so I'm hoping someone will know the size or have a solution.

 

You got a pic of the plug you are talking about? Is it on the front cover housing? You got my curiosity up. Is it the coolant temp or oil temp you are attempting to monitor.?
There are three plugs in the front cover that I am aware of. The outlet and the inlet to the oil cooler that was put on earlier D2's (both relatively close to the filter) and one close to the factory oil pressure sending unit.
My Bad, i just noticed you are asking about a D1. Although the plugs may still be the same.

 

This plug. Goes into the hole right above it.

 

I bought the same adapter that Tom did here.
https://landroverforums.com/forum/bu...30/#post479683
Problem is my sending unit is 1/8 MIP thread, so by the time I put another bushing in there I feel the end of the sending unitis going to be quite a ways from the coolant flow. Hmmmmmm

 

I saw some sending units that look fairly long that come with adapters if the probe on your sending unit is fairly short.
Stewart Warner 280EC Electric Water Temperature Gauge Sender

 

Interested in why you feel compelled to install a temp gauge when, if I recall correctly, you have a smart phone app with real time OBD data available?

 

For me personally, I want a 2nd opinion(LOL) on my temps, in case factory fails for some reason.

 

I have an 8 or 9 hr trip coming up and thought it would be nice to not run the Torque app all the time. If nothing else I can use the gauge on my 95 where OBDII data isn't an option.

I've got about 25 miles on the new gauge and I've noticed the temp readings are consistently 10° higher than my OBDII temp reading. Not sure what's up with that but I feel the probe kn the sending unit is recessed too far out of the flow of coolant.

 

Drill and tap the plug you pulled out of the intake. Just sayin......

 

Man, I posted the size on this forum somewhere. Let me find it. I ended up doing two adapters to get the 1/8" NPT sender in there.