Know your Glow Plug System, and which one you have!

Four systems

System 1 is a "Slow Glow" system controlled by a module (12 volt) System 2 is a "Fast Glow" system controlled by a module (6 volt) System 3 is a "Fast Glow" system controlled by a thermal controll (6 volt) System 5 is a "positive Temperature Coefficient (PTC) plug (6 volt) Selecting the correct plugs is VERY IMPORTANT!! For instance:.. *If you put a 12 volt plug in a 6 volt system, it wont heat enough to start the engine easily *If you put a 6 volt plug in a 12 volt system, it will most definatly burn up causing major in removing the heads to get out the broken glow plug...not very cool!! How Do I know which Glow Plugs to get, you ask?....well heres how: The Older 12 volt "Slow Glow" used from 1978 to 1979 is stamped 7G below the threads, and has a 1/4" terminal and a black insulator. The 6 volt "Fast Glow" used from some 1979 till 1983 is stamped 8G below the threads, has a 5/16" terminal and a black insulator The 6 volt PTC plugs used from 1984 till the end of production is stamped 12G below the threads, has a 1/4" terminal and a tan insulator

Ok, but is my system thermal controlled or module controlled?

Heres an easy way to find out....face the engine and look at the left front corner (passenger side) of the intake manifold...there is a screw in thing with wires hanging out...kinda looks like a engine temperature sender...but thats on the right front corner near the thermostat housing, anyways, if it has a single wire conected, then its module controlled, if it has this big wire harness with 6 wires then its thermal controlled

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