15,000 mile oil change interval

[nthach]

Originally Posted by jayman

Or, I could have kept using the bulk dealership oil that was contaminated with sulfur, rust, dirt, and water. Without a virgin oil analysis, I never would have tracked down the alarming used oil analysis my Prius had when new.

Even virgin bottled oil is subject to Fe(rust), Si(sand or dirt) or water contamination due to the plant it was bottled at - take a quick stroll at the VOA section at BITOG, Castrol is the worst offender there.

Dealerships buy oil in bulk from whoever - we buy Quaker State at work. It's piped into holding tanks, and God knows what is going on in the tanks. And water/dirt will settle in the tanks, filters and pipes - even copper pipes will get attacked.

FWIW, I'm sticking to a 5K OCI on 3 cars with Pennzoil Platinum.

[jayman]

Originally Posted by nthach

Dealerships buy oil in bulk from whoever - we buy Quaker State at work. It's piped into holding tanks, and God knows what is going on in the tanks. And water/dirt will settle in the tanks, filters and pipes - even copper pipes will get attacked.

I'm not talking about the expected contamintaion, which is generally very low. I'm talking about contamination 20-100x expected

I thought it was common practise - expected practise - to have desiccant filter/breathers on bulk tank vents. As ambient temps change, and as the tank volume is drawn down, ambient air has to be drawn in.

The desiccant breather/filter allows ambient air to enter, but keeps out moisture and dirt. HOwever, every dealership bulk tote bin I've seen to date, has nothing more than a simple inverted pipe with a screen for a breather

So that simple inverted pipe keeps out rain, and perhaps larger bugs and mice, but allows dust, dirt, moisture, etc, to enter the tote bin. In most industries, its standard practise to use desiccant breather/filter assemblies

Why doesn't the dealership use one? Because it costs about $100 a year to change the filter?

Let's not even get into the low-bidder-of-the-week supplier of the oil contract. There is a good reason why I do my own oil changes