Is there anything wrong with these glow plugs? I just finished replacing them in my '97K2500 w/6.5TD because I've never done it and the motor has 180k on it. Don't know what a bad plug is supposed to look like. left side was piece of cake, right side I removed the tire and splash gaurd, and I drilled an access hole for get at number 8. 2,4,6 were accessible with the splash gaurd removed.