farmer boy
Well-known Member
A couple months ago i posted about a 1997 GMC Sierra 305 that was getting terrible mileage. About 10 miles per cdn. gallon. Had to drive it about 15 miles to work every day so it was affordable but still an unneeded expense. The truck only ran at about 160F so i replaced the thermostat with a 195F and no difference in temp. I left it that way for a while but I decided about a week ago i would try blocking 2/3 the rad with some cardboard. Didn"t want to cover more because of the trans cooler. I ran it around the block. Total of about 6.5 miles. First 3 miles I ran it easy like normal but the temp didn"t go up at all so i ran it as hard as I could and finally got it up to 175f but it wouldn"t go up any higher. Now the truck is getting 16.5 to 17.5 mpg and would get better because quite a few of those miles were with 7-800 lbs in the bed.and a few 2 mile trips.Any idea what would cause the mileage increase? Would running it hard help somehow?