hi, i have a 1981 300d i parked one cold snowy night and left it a couple days until the snow melted away and since then i cant get it started, the glow plug light works the engine turns over , ive taken the battery out of my 300sd and tried in the 300d still wont start, ive done the glow plug relay tests, checked the glow plugs with ohm meter,the car has never in the five years ive had it not started,the battery was brand new 8 mos. ago and the neutral sfety switch was replaced a year prior. it seems it wont turn over fast and crisp enough to get it going. any thing any one can suggest . thanks gordon