moved to Laramie Wyoming for a year.last night was about 0.my truck almost did not start.the battery is less than a year old,had it on a maintainer the hole night because it helps on 20 degree nights in the morning. running 10w40 oil(over 240k orig miles),new starter.all my lights were nice and bright but it was a very slow crank. should i go thinner on oil or would a oil pan heater be a good idea?no issues at all if above 25 degrees just below.

87 dodge power ram 50,35" tires,5 1/2" total lift,4.6 gears,lockers front and rear,Rancho RS5000's,custom front bumper,custom rock sliders,cct extended diff breathers,75 amp alt(40 amp stock),thorely header,K&N,wheeled hard...