His motor is for sure getting that hot ie, 220 if he could confirm it with the pyrometer. What is not registering correctly is the gauge which is showing 160 but is seperate from the function of the electric fan. I belive the gauge is showing 160 because the thermal couple at the end of the temperature gauge sending unit is not completly submersed in coolant. The shape of the "T" fitting could not be allowing the coolant to come up into the fitting far enough to completly submerge the sending unit which is sometimes the case with a "T" fitting, and thus gives a false reading. The same thing could be going on with the temp sensor for the fan, now that it is in the "T" fitting, it is now not completly submerged in coolant and is also registering a low reading just like the sending unit for the temp gauge. The mechanical fan will keep the car from overheating but the car will still run hot because the mechanical fan is only covering half of the surface area of the radiator. First thing is to get the temp gauge working so that it can be determined when the fan should be coming on, which is 217. If it were me, I would get the "T" fitting out of there and use the inline radiator adapter ( which I attached the link to in my previous post) for the temperature gauge sending unit. Also do a check for the in line radiator adapter on ebay there is guy that has them for 20 bucks or so. Then I would put the temperature sensor for the fan back in the thermostat housing like it was before. The reason the fan comes on when you pull the plug going to the temperature sensor is because your electric fan circut as it relates to your temperature input to the ECU is intact and working properly, by pulling the plug on the sensor it mimics high resistance. Which is exactlly what the temperature sensor for the fan does, when it gets hot the sensor increases the resistance in the circut, thus telling the ECU to turn the fan on. That is not saying anything for what tells the fan to come on in the A/C circut though. The temperature and A/C circuts as they relate to your electric fan are seperate as far as I know, so one is not dependent on the other for the fan to work. Like I say, get the in line radiator adapter and put your temperature gauge sending unit in that. Then put your temperature sensor for the fan back where it belongs in the thermostat housing. Also, make sure you are getting the correct temperature sensor for the fan, make sure the folks down at the parts store are not giving you a temperature switch or temperature sending unit. I did a quick search over the internet and I will tell you right now that there is no temp sensor/sender from a '98 XJ that cross references to your '96 XJ. The temp sensor/sender for the '98 XJ is the same sensor/sender for my '01 XJ. So, you do not need a sensor/sender from a '98 XJ, it will not work. You need a temp sensor for a '96 XJ, which begs the question why the plug on your wiring harness doesn't match the sensor for a '96. Did someone replace that plug at some point?

 

I checked the harness it looks all original. No breakes or wire splices. I do know that the fan was running before overheated and cracked the head . That was from a broken heater valve and nowhere to stop. I will give the rad adaptor a try. as for the fan sensor I have no good answer for this differance.

 

So when I did a search for the sensor for your car last night it gave me three options all of which had a description of Coolant Temperature Sensor all of which were not compatable with a '98. Then I did a search for a '98 and it gave me 5 choices all of which were called Coolant Temperature Sensor/Sender and were not compatible with your car. Now when I do a search for your car it gives me like 5 or 6 choices some are the sensors to your fan and others are senders to your gauge? IDK, too me it just sounds like you are not getting the right part or something. Anyhow the link to the page I am looking at is attached below, take a look and see if the two sensors on the top have the same plug type as your car. If you can't get this figured out, then you are going to have to wire in an aftermarket sensor and thermostat. That might be the way to go, then you would be able to control what temp your fan comes on at with the turn of a dial, nice to have in the summer.

http://www.oreillyauto.com/site/c/se...erature+sensor