What weight of motor oil for a 2003 Chevy Silverado 2500HD with a 6.0 L gas engine?

Answer 1

Look at your owners manual if available, if not then sometimes the oil cap has what it should be. How many miles does it have? The reason why I ask this is if you do have close to 100 thousand the I would sudjest using a blend of 10w-30 synthetic. This will clean your engine, but also help on fuel mileage. If you go to straight synthetic I have heard that it cleans the motor to fast and you start getting leaks. Work up to changing to straight later on down the road. If you are towing heavy trailer then you can look at going to 10w-40. Give that little extra cushion for the bearings, but you will need to let it warm up a bit if you are in a cold climite area. Or use 10-40 in the summer and change to 10-30 in the winter, can be a pain to remember but it wont hurt.