I was working on replacing the hoses and thermometers on my disco, and I could not find any data on the differences over time for the thermometers. So I’ve put together some information.
The left thermometer is the stock one that was installed in 1996 in my truck. the right is the replacement part (etc4765). The changes are that It looks like the actual heater coil got bigger, and got fins on it. so it can soak up heat faster. The closer spring diameter is thicker, wound the other way, and has less turns. There is a bypass to equalize the pressure between both sides of the thermometer, and the stamping to retain the thermometer changed a bit. The diameter is the same, and I’ve put a standard socket to show size.
The gasket is fairly normal, so I’ll skip over that.
The filler neck I had developed some weeping holes, so I re-welded it, machined it and then gave it a good shot of paint. There is a bung here that could be used to add an external temperature sensor such as a ACDelco 213-77, or 15326386. The casting lines still showed, and that spot for the temperature sensor was not flat, so in a flury of dramatic OCD-ness, I fixed them.
The actual install is fairly straight forward, and it’s located underneath the intake runner, towards the front. right of the alternator from the front of the truck. The spigot curves up and to the left.