Just thought I'd let you guy's know the Mobil Delvac rebate is on again. You have to find a participating retailer. Here in MN, Mills Fleet Farm has the Delvac II Esp 5-40 diesal full synthetic on sale for 19.99 a gallon and Mobil is offering a 10.00 a gallon rebate on up to 5 gallons. A 5 gallon bucket is 99.99 but the rebate is only 40.00 dollars. I know oil is something everyone has a opinion on or favorite brand, I use this and love it. Just a FYI.