My temperature gauge (IIRC) has always read about 200. The last couple months
(I only drive my truck every so often) the aftermarket gauge (http://iequus.com/Product/8162/1-1_2...perature-Gauge) now reads 160-170. The day temps are only in the 70's but shouldn't the thermostat (new-195 deg) bring it up to above 180? I drove the it today for awhile with the AC on full and it only got to 170. I have checked the connections both power and at all points, removed and cleaned the temperature sending unit. Should I buy a new temperature sending unit or is it most likely a bad gauge. As near as I can tell the factory gauge reads about what it always does. Anyone know what the resistance value of the temperature sending unit should be cold/hot ? Any other ideas? Shouldn't the top hose get too hot to hold? It doesn't.

 

did you check the coolant level?

if low it may not heat the sender

 

Have you changed the Thermostat? Mine did the same thing, but unfortunately for me it was in the middle of winter.

 

New thermostat,full of coolant.