Mike, with mine, it stopped working and started frying the instant that power was applied. It took a millisecond for it to be ruined. I doubt you'd seen any intermittent problem if you were missing the insulation across the temp gage. It would either work, or not.
If you are having an intermittent problem, I suggest looking at the continuity at the temp sending unit at the block and the wire connections both at the sending unit and at the gage. If that was good, then you might consider looking at the power wire's connection at the gage and whatever you have the other end connected to.
Bill
