[Phil Waterman]

I've picked up 3 or 4 of these units for the early style Chevy temperature gages on e-bay, sort of pick my chances and if I remember correctly I've never bid more than $30 US. They do have different lengths (I've seen three different) which has not been a problem. Even the shortest ones are more than long enough for the Patter 12. Given the location of the temperature gage in the panel of the Pattern 13 there is a problem while the tube is long enough to reach the hole in the engine compartment it runs dangerously close to switch terminals. It is also a tight fit to the mounting point at the back of the head. You have to be careful in removing and installing the valve cover.

I mention the switch clearance because this has been the death of two gages in twenty years. Short the tube to a live 6 volt power source and the unit is dead. So when you are installing the unit to disconnect the power. After having shorted one out trying to tighten a loose connection behind the dash I shorted the tube on one occasion. The next one I installed I very carefully enclosed the tube in electrical tape.

One last point always check a new unit prior to installing the boiling water test is the best dip the bulb in boiling water and see if the unit registered something near 212 on the gage. (What ever you do not use open flame to test the bulb saw this done at a flea market you can guess the outcome.)