Annual oil changes

iamdub · Oct 20, 2017

Z15 said:
Oil Myth: The color of the oil indicates when it’s time for an oil change

It’s common to assume motor oil that has turned black has worn out or become too saturated with contaminants to protect your engine and requires changing. Not necessarily. Discoloration is a natural byproduct of heat and soot particles, which are too small to wear out your engine.

The only surefire way to determine if the oil has reached the end of its service life is to perform oil analysis. Chemically analyzing an oil sample reveals the condition of the oil, the presence of contaminants, fuel dilution and so on. Absent oil analysis, it’s best to follow the oil-change recommendation given in your vehicle owner’s manual or by the motor oil manufacturer. The recommended service intervals for AMSOIL products, for example, are based on thousands of data points spanning years of use.

It’s best to trust the data, not your eye, in this case. Otherwise, changing the oil could amount to throwing away good oil.

Interesting and true, but I have nothing to go on but color and mileage. For the cost of an oil analysis, I can buy 4 of the required 6 bottles of new oil. I might be throwing away still good oil, but at least I'm sure to have good and clean oil. If I followed my Tahoe's oil life monitor, the oil would be changed around 10K-15K miles. I don't take much stock in the oil manufacturer's generic recommended OCI's of 3K, 5K, 7,500K, etc. miles. Other than that, they typically just say to follow the vehicle manufacturer's recommended schedule. So, yeah, I would probably be fine with a 10K OCI. But changing it every 5K when I rotate my wheels keeps me sane.

I wonder how difficult it would be to design and build some sort of at-home mini refinery to filter the used oil to remove contaminants...

swathdiver · Oct 21, 2017

Regular oil is dead by 5,000 miles. Rub some between your fingers...

As for me and my house, we run synthetics and for the last seventeen years or so have been using GMs oil life monitors. I think with this truck though, I'll change it when the monitor says 25% or 33% life remaining. The latest programming doesn't let it go past 7500 miles no matter what.

iamdub · Oct 21, 2017

I wasn't even thinking about conventional oil in my reply, but I know what you mean. Old dino oil feels like it's just thick water between your fingers.

Annual oil changes

iamdub

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iamdub

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