Heads up to those of you running 15w40. Mobil has a promotion running until May 31. $4.00 off a gallon or $20 off a 5 gallon pail of Mobil Delvac 1300 Super 15W-40 oil. Walmart had the gallon jugs for $9.99 last time i was there.
Link to the rebate:
Mobil USA | Heavy-Duty Engine Oils | Mobil...