I bought a 300td about 2 years ago and after 35000 miles i decided to check the valves. They were about.010in and .012in. the car was starting rough or not at all if it was cold (20F-30F). I already tightened up the vacuum system and ran two diesel purges which seemed to help for a day or two. from a previous 300 diesel i owned ,that had similiar symptoms, i noticed the car started better with about .012 and .015 clearances. I adjusted to this clearance and it helped a little. i know these settings are looser than called for but it seems to help. Is there risk to the engine at these clearances? the car still starts rough and im wondering if it might be impossible to have a perfectly cold starting engine. Does anyone's high mileage (200k+) 300 enigine start in sub feezing temps on the first or second glow with out a block heater and without giving it some pedal?