Originally Posted by Rookie84

You can actually go 5k without any problems at all with just about any oil. 3k interval is a marketing fluke. I came upon one website which tested some oils and Mobile 1 lasted 15k miles. But they were topping off the oil and said realistically the oil should like 10k miles w/o problems. So unless you track your car, 5k miles interval should be just fine.

Originally Posted by romanwarrior

your comment prompted me do some research and you're right it's not necessary to do an oil change every 3K miles. I'm going to start doing mine every 5K-6K miles with Royal Purple oil and save myself some money.

Originally Posted by Rookie84

Here is what I found about viscosity numbers:

Is there a disadvantage to using an oil that flows better when cold, i.e. 5W30 versus 10W30?


Sometimes, but usually not. The crux of the issue is this: the bigger the difference between the cold oil viscosity and the hot oil viscosity, the more the volume of viscosity modifiers and the less the volume of base stock. If you are good about following the manufacturer's recommended oil change interval then stick with the 5W30 if that is the preferred oil for your vehicle, even if 10W30 is acceptable in warmer climates. Older cars may specify 10W30 only. This is because they need a little more viscosity when cold to keep a protective film on the cylinder walls. There have been instances where the larger amount of viscosity modifiers that are present in 5W30 have broken down due to excessive heat and have left carbon deposits on the valves, but this is extremely rare. The proper fix would be to reduce the excessive heat, but the workaround was to use an oil with less viscosity modifiers.

Originally Posted by ballisticus

Use M1 5W/30 ($21 for 5 qt. jug @ Walmart) and change it at the 7500 mile regular service interval. Warrantee will still be intact and you save even more money. Now that Im out of warrantee, I change every 10K miles with M1 5W/30 and the motor runs perfectly.