Before crossing the border at Lukeville, AZ(Gringo Pass) we stopped to price diesel. Since diesel was $2.33 per gallon we decided to fuel at a Pemex station. The cost in Mexico was 4.840 per litre. When converted to U.S. dollars the cost is $1.93 for four litres or slightly more than one U.S. gallon. The Duramax ran quiter and cooler on Pemex.