When Should you change your Oil?

I can’t tell you how many times people have asked over the years what oil change interval should I use?  I’ve it heard tons of times, “I’ve got 4000 miles on an oil change, how much damage am I doing my to my car”?

As a mechanic I wrote out thousands of oil change stickers.  Telling people to come back in 3000 miles or 3 months for synthetic blend oil, and 5000 miles  or 3 months for full synthetic oil.  I did this because it was company policy.  The question is was it right oil change interval?

How often to change your oil

The answer to the proper oil change interval really depends on many things.  Most importantly making sure you change your oil before it gets too “dirty”, and is no longer protecting your engine.  However they are mainly based on how many miles you drive and the type of driving you do.

Every single suggestion on when to change your oil is just that, a suggestion.  You can base the miles of an oil change on driving style and conditions.  However, if you truly want to know the condition of your oil have it tested.  To be fair I’ve never gone as far as having my oil tested.  Although that’s the only way to be sure you’re not waiting too long to change your oil, or changing it too soon for that matter.

Have your oil tested

If you choose to have your oil tested here are a couple places that will test your oil.  Blackstone Labs or Amsoil will test your engine oil to determine if it’s still good or doing damage to your engine.  They can also tell you the condition of your engine.   By having your oil tested you will gain lots of knowledge on the condition of your oil.

This knowledge will help you decide if you are changing your oil too often, or maybe not often enough. It can also tell you the condition of your engine.  If there is coolant in the oil.  Also the amount of metal shavings in your oil.  The only reason I’ve never had any of my vehicles oil checked is because I change my oil often enough that I have no worries about the condition of my oil.

Manufacturer’s suggestions

If you choose not to  have your oil tested what oil change interval should you use?  You can always go by the manufacturers suggestion.  By going with their recommendation you will not have to worry about voiding your warranty,  but you may not be doing what is truly best for your engine.

With so many manufacturers offering free maintenance for the first 3 years of a new car it makes since they would try to keep this cost down.  If you change your oil at 10,000 miles instead of 5,000 miles manufacturers have to pay for half as many oil changes.

If you’re one of the few drivers that drive under “normal driving conditions” than the manufacturers are right when they say 10,000 miles is fine for a full synthetic oil change.  I will warn you, shops have been seeing an increase in oil related repairs later on in car’s life more and more since the onset of extended oil changes.  Timing chains are wearing out early, lifter problems and other things.  Which can be a manufacturing problem but also could be caused by dirty oil.

Conclusion

What is the best oil change interval?  Unless you commute to work more than 20 miles a day each way, giving your car a chance to fully warm up and cool down, I suggest you change your oil at 3000 miles if you use conventional oil and 5000 miles if you use full synthetic, as your oil change interval.  I make this recommendation based on the fact that most people drive very short trips in stop and go traffic.  This is extremely hard on you engine and your oil.  With new cars using oil for cooling, lubrication, and hydraulic pressure for variable camshaft timing.  It’s a good idea to make sure your oil is good and clean.  Even though you could extend this mileage out longer, without oil testing do you know for sure?  Plus, is the cost of an oil change really worth possible damage to your engine and shortening the life of your car?