1994 Dodge Ram Heating problem
Have a 1994 Dodge diesel . Have had it for the last 20 years and am still having a problem with the motor temp. It will heat up to 185 then drop down to 145. Then work its way up to 185 then drop back to 145. Have changed to thermastate 4 or 5 times with no change. Runs just fine but will not keep a costant temp. Any ideas out there.