15,000 mile oil change interval

Yep, physical properties of water for heat transfer are greatly superior to straight ethylene glycol or propylene glycol. Thermal conductivity, heat capacity, viscosity, wetting characteristics, as well as heat of vaporization.

 

Pretty expensive distilled water eh! If it is real distilled water then the anti-corrosive characteristics should be sufficient. But do you trust them to put in the real thing? LOL I would rather go buy the real thing and dilute it myself. Water is a strong corrosive agent without distillation.

 

If you really want to ruin a radiator, let a "mechanic" mix the coolant with whatever comes out the tap, even if that should be hard water

 

Ditto!

Nursery water in about $1.25 and distilled water is 88 cents at Wal-mart.

 

Just think how annoying it would be for the container of SLLC to spontaneously spring a leak just sitting on a bench in the garage. That happened to me a few weeks ago - I lost about half a gallon on the floor before I figured out where it was coming from.

 

Well I'm doing that and I do not consider myself lazy. However I'm using a high quality synthetic (Amsoil 0W-30), performing analysis every 10k miles, and tracking the results to see what is changing. The motivation for doing this is:
a) This is how professionals maintain engines, especially expensive ones
b) It rewards the high grade oil makers, not the cheap oil makers
c) It reduces the waste of replacing good oil at a high rate
d) Eliminates the dealer possibility of mistakes and errors (of which there are quite a few horror stories).

Is this a bad idea?

 

I think it is reasonable to extend the OCI when accompanied by UOA.

 

what about the filter, are they designed for this?

 

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.

Naturally, Toyota Canada blamed my use of Mobil 1 for the lab reports. Once the lab suggested snagging a sample of that dealership oil, Toyota very promptly STFU

 

If it is a high quality filter, then yes, it is designed for this. The Toyota OEM filter has been shown to be high quality. I use a Amsoil Filter or a Toyota Filter.

Note that the European oil change intervals of the Prius are for much longer using the Toyota filter. That makes it fairly clear that Toyota plans on their filter being used for long intervals.

 

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.

 

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