Oil Change Intervals
Is changing your engine oil every 3000 to 5000 miles necessary? If you drive gently and only drive on the highway in moderate temperatures or don't plan on keeping your car more than 90,000 - 150,000 miles on the odometer, then you can probably extend those oil change intervals.
How you drive and what kind of driving you do has a lot to do with how long you can go before you change your oil.
Mechanics who work on engines recommend oil changes every 3000 - 5000 miles not because they like doing them, in fact oil changes are not high on their prefer to do list, but because they constantly see the difference in vehicles that have been serviced regularly and those that haven't. Plugged oil pump inlet screens, lifter or other engine noises, stuck piston rings, loss of oil pressure, premature engine wear or failure - all symptoms of extended oil changes.
Some engines are more forgiving than others. Some can withstand abuse to over 150,000 miles while others may show symptoms by 70,000 miles.
Engine oil carries metal that has worn away, dirt and moisture from the air and combustion gasses that gets past the piston rings and sludge from chemical processes. These materials increase friction on metal parts and seals and causes seals and gaskets to harden.
These contaminates also dilute and wear out the additives in the oil that maintain viscosity and counter sludge formation.
The cars we see lasting more than 200K or more are usually cars that were serviced a little more frequently than manufacture recommendations and of course the manufactures don't really want your car to last to 300,000 miles or more.
The extra cost of oil changes every 3 to 5 thousand miles versus 6,000 or more is a lot less than most engine repairs. Using a good synthetic oil is a better way to extend those oil changes up to 10,000 miles or more.
Engine deposits and wear are slow, sure killers of performance and engine life. In most cases, by the time you are aware of an issue, the damage has been done and often cannot be reversed without a major engine repair or replacement. Changing the oil in a vehicle at the appropriate drain interval is the easiest, most cost-effective insurance against lubricant-related engine damage.
Why change oil frequently when not due by mileage?
Vehicles routinely driven short distances, especially in cold weather will build up moisture in the oil from condensation and combustion gases by-passing the rings.
This build up of water will cause acids to be created within the oil resulting in the formulation of sludge and accelerated wear.
There are additives in the oil, which are designed to combat these acids, but they deplete over time, and can only control so much moisture.
Lots of short trip driving, especially in the winter, doesn't evaporate the moisture out of the oil like longer trips do. Don't wait for that 3 or 4 thousand mile interval if you do a lot of short trip driving and put less than a 1,000 miles a month on the vehicle.
Should you do Engine Flushes?
Winter Time Oil Grades
Oil viscosity can make a big difference when it comes to getting lubrication to the furthest parts from the oil pump, which is usually the valve train. Besides improving gas mileage, if it gets near or below freezing where you live you should definitely be using a 5w-30 oil.
Why? Consider this: 5w-30 takes 10 seconds to reach the valve train at 15 degrees Fahrenheit, compared to 20 seconds for 10w-30. Even worse, while 5w-30 is flowing freely in 40 seconds 10w-30 weight takes up to three minutes. Even better, consider switching to a synthetic oil, which will flow freely in 15 seconds at 15 degrees. Always refer to your owners manual for oil recommendations.
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