Hi

I am now the proud owner of 4 240 dl sedans. 2 are 87's, 1 is an 86 and the last one which I will be using for parts is an 84 DL. The 86 and one 87 has a similar problem that the temp gauge needle is erratic. On the 87 it will sometimes move to a normal temp range, sometimes it at the bottom, most times it is about 1/2 the normal range. I changed the thermostat on the 87. No change. The 86's needle just moves up a bit (not much) from the bottom. Have not checked the thermostat on it yet. Thought about changing the sensor on the engine, is that a good place to start. How do I diagnose it. Any suggestions. Thanks