On my 89 xj I have a ongoing issue, I recently replaced the motor with a 87 xj 4.0. everything works great! Except the temp guage, I thermoed the engine and the coolant temp was 195 at running temp. But my guage reads 230 deg. I replaced the guage inside 2 times both are good but same problem,then replaced the sender on the cylinder head with 3 senders all did the same thing even tried a different sender and that just didnt work. Checked the grounds all ok what the hell else can it be???