Why do people still change oil every 3 months or 3,000 miles. Almost all mfg's now say 5,000-7500 miles?

Oil is the life blood of your engine. The newer/cleaner you keep the oil in your engine, the less wear and the longer the engine will last. Less wear internally also equals better fuel economy. Oil changes is cheap investments in the long run of keeping your engine lasting a long time.

because if you spend $40k on a new car what is the best insurance for it to make it last by spending $25 4 times a year. That's not a lot of money $100 a year for general maintenance. But your facts are wrong most people do not change the oil every 3000 miles. If you have done any reading about it the average person changes their oil 4800 miles or so. And a lot even more. Plus 70% of the new cars on the road are leased and people dont give a crap about them just like renting an apartment vs owning a home. Homeowners take much better care than renters because they are the ones that have to fork out the money when something breaks. Plus one thing that people dont understand is that manufactures are in the business to make and sell as many cars as they can. If they could they would tell you to change it every 20k miles. Plus read your owners manual a little closer and see if you really fall in the 5000 mile change. If you do extreme driving then they still recommend 3000 and 90% of people do extreme driving wether they think so or not.

Dear Koma-

The respondants on your list are all partly correct. Let me take this opportunity to do a little Automotive 101 for you.

The oil that goes into your engine does not wear out. It is the additive packages and cleaning agents added to the oil that become overloaded and are unable to perfrom their services within your engine.

These additives are engineered into the oil to improve its lubricating and cleaning abilities.

Oil does the all of the following things in your engine. It cleans, lubricates, flushes and suspends debris, and cools the engine parts. The additives in the oil help the oil do its job better and prevent it from being easily burned off from engine heat and frictional forces.

As an engine heats and cools a natural occurance called condensation occurs inside the engine. This condensation mixes with contaminants such as unburned fuel or partly burned fuel and mixes with the sulfur compounds to form sulfuric acid. This acid if allowed to build up will damage engine parts such as piston rings, bearing surfaces, valve guides, crankshaft bearing lands and any other parts the oil has contact with.

The formation of engine sludge allows this acid a harboring location in low circulation areas to destroy oil pans, cause internal rusting of parts, or if the location is near an engine bearing, can cause the bearing to fail under high stress situations. Normally when you are demanding the engine's top power, like getting onto the highway or passing a slower vehicle, maybe even climbing a hill.

So to control this we recommend 3000 miles or 90 days whichever occurs first. This keeps the oil in good condition and keeps those contaminants to a minimum. The reccomendation from the manufacturers to change the oil every 5000 to 7000 miles is insurance they are going to be selling you a new car at 150,000 miles, instead of making a small repair such as gaskets or seals.

If you are going to use Synthetic Oil you can push your oil change intervals to about 4000 miles.

For the record ask yourself what is the greater waste of money. Replacing the car every 100,000 miles and having high repair bill costs, or doing a little extra preventative maintenance and keeping the car for 20 years versus the average 8 to 10 year lifespan.

Keeping your fluids changed and the vehicle tuned up is the best thing you can do for your vehicle. It not only saves you from having to come up with another expensive downpayment, but its cheap insurance that your car will be running reliably for longer.

Here is what we use in the field.

Coolant- Annually

Transmission Fluid- Annually

Engine Oil and Filter- 3000 miles or 90 days

Tune Up- Biannually

Air Filter- Annually

Fuel Filter- Annually

Rotate Tires- Every Other Oil Change

A/C System- Annually

Power Steering Flush- Biannually

Brake Fluid Flush- Biannually

The Brake Fluid Flush is a very critical service. The ABS Systems need to have very clean brake fluid. The control valve that makes the system work has very small control valves within it. So dirt and debris that gets into the system needs to be flushed out periodically to ensure the system is operating correctly. I do consider that serivce a safety item, so you might want to have that system serviced if you have not.

Lastly, waiting until the oil light turns on is the worst thing you can do. On some cars they do have that attached to milage to remind you to change your oil, this is true. But on some vehicles this indicates either low oil pressure or low oil level. If this indicates low oil level, you are doing more harm than good.

Improper Oil Level will eventually cause severe engine damage. As a rule I normally check my oil level when I fuel the car, if it needs oil, I add it then.

Well I hope I helped you out. Good Luck!

Actually, very few cars (and mostly GM models at that) have oil life monitors. And while many cars have maintenance intervals of say 7,500 miles, you have to read the fine print. Cars will typically have 2 maintenance schedules - Regular and Severe. Regular might be a 7,500 mile interval but severe is usually a 3,000-3,500 mile interval. If you read the fine print in the maintenance schedule you will find that 99.9% of all drivers qualify for the Severe schedule.

And the old oil does get recycled.

if the manufactures stand by their products, we will follow their schedule maintenance. the average vehicles only guarantee their vehicles 3 or 5 years. this is a sign of cheap made vehicles. we have compare vehicles that change their oil according to the light and found alot of sludge forming inside the engine. we experience a Mercedes and found out the engine bearing was bad due to sludge build up. the warranty cover only 50,000 miles. the owner of the car was very upset. so just because the manufactures claim their vehicle will tell you when to change the oil does not mean it good for the engine. it all talk but no action!!!!!!!!!

Italyguy is right. It is probably just fine to wait 7000 miles to change your oil, but if you think about how much you spend on oil changes compared to other things. My car gets 30mpg so in 3000 miles I use about 100 gallons of gas, right now that's about $275 worth of gas. I use Mobil 1 full synthetic (change it myself) and still spend less than 25 bucks to change my oil. That's less than 10% of the cost of fuel. I plan to change my oil every 3000 miles because sometimes I don't have time. Maybe I won't get to it 'til 4000 miles. Fresh clean oil is always better than old used oil. It's up to you, but it's hard to regret changing oil more often.

follow what the handbook or the producer tells you. in my opinion, I basically replace my oil each and every 15,000 miles with Mobil a million prolonged Mileage guy made and a cellular a million or ok&N oil filter out. I tension approximately 35k miles according to three hundred and sixty 5 days.

The mfrs probably want the engine to wear out quicker and keep them in business! Every 3000 miles is fine.

Because they aren't using Mobil One SuperSyn with a good filter.

To answer this, it's a standard process that most people used before electronic odometers came about. Secondly not everyone has a luxury as this, so you go with what you know.