Engine Oil Change

[A.J.]

I remembered reading that California is starting a campaign against 3000 mile oil changes (California launches campaign against 3,000-mile oil changes) and I started wondering about my own oil changes.

I follow hypermiling tip #1 (drive less) pretty well, and drive only about 3,500 miles per year. But I change my oil every 6 months (meaning only after about 1,750 miles). The manual even recommends every 4 months, if you live in Canada, which is my case, but I find that pretty extreme and annoying. I usually use Mobil Synthetic 5W-30 oil and Purolator PureOne filters (the gold ones).

What would you guys say, would I have any problems (e.g. sludge in the engine, etc.) if I started changing it every 11 months and 3000 miles (which is the recommended distance interval) in order to be more eco-friendly and waste less oil (and time...!)?

[CigaR007]

By all means, extend your oil change interval, especially if you are using synthetic oil. My car calls for 8000 km (5000 miles) using regular oil. With synthetic, I am looking at 12000 km or once a year.

[SentraSE-R]

If I were you,I'd change my oil every 18 or 24 months.

[Thymeclock]

Originally Posted by A.J.

What would you guys say, would I have any problems (e.g. sludge in the engine, etc.) if I started changing it every 11 months and 3000 miles (which is the recommended distance interval) in order to be more eco-friendly and waste less oil (and time...!)?

It depends on the type of driving you do. If you do all (or even mostly) city driving the recommendation is to change the oil more frequently based upon time rather than distance. The more severe use of city driving involves more cold starts, etc. which reduces the effectiveness of oil.

Decades ago I did my oil changes less frequently and ended up with an engine that had considerable sludge far before the 100,000 mile mark. Now I change the oil and the automatic transmission (partially - drain and fill) every six months, regardless of miles traveled. If you are doing taxi cab type driving (considered severe duty) most manufacturers recommend the oil change be done at every three months.

Frankly I don't care about being eco-friendly at all; I'm more concerned with preventive maintenance and longevity of my engine.

[gone-ot]

3-5K on dyno-juice; 5-10K on man-made monkey-juice.

[lowglider]

I would change it every 24 months if it does not start to sludge before. Just check the oil˙s condition every few months and you`re on the safe side, Mazdas have great engines, that engine can go for a 100 years with that annual mileage:>

A friend of mine has a newer Opel with an 18000 mile oil change interval and 95% of that car`s journey are cold starts and less than 3 miles of driving. He forgot about changing oil and drove over 20000 miles with one oil. The oil did smell of gasoline, but was didn˙t even look that bad and the there was hardly any sludge. Good synthetic oils can go for a very long time.

[A.J.]

I drive 60% city, short distances, lots of cold starts (temp goes down well into the negatives (F)), lots of EOC to the (super long) red lights, and lots of re-starts...

[Frank Lee]

It's about time a govt. said something about this.

[Ryland]

Seems like a perfect case to get an oil analysis done, after all you don't want water condensing in your oil or the oil becoming acidic or diluted with fuel.
I didn't know anyone still recommended 3,000 mile oil changes, my car says right on the sticker on the air filter and in the owners manual to change it every 7,500 miles so I put synthetic in and change it every fall with 10,000 to 12,000 miles on that oil change and haven't had any oil related problems.

[IsaacMTSU]

Our Honda CR-Z checks viscosity at every restart and some go 20k without the car saying the oil has broken down. The manual recommends 10,000 miles with synthetic 0W-20