"Xeno" wrote in message
...
On 28/3/21 11:13 am, mike wrote:
On 27-03-2021 21:14 Scott Dorsey wrote:

Yes, that's why you test it.

Of course.
Under the logic of most people here they should replace the oil daily.
That's because it breaks down daily.

Oil in the engine is undergoing a continuous breakdown process. Actually,
if the truth be known, it is the additives in the oil which are breaking
down. So, when dealing with oil change intervals, two factors need to be
considered; additive depletion and oil contamination. These are like the
proverbial piece of string - there is no hard and fast rule on when
additives are sufficiently depleted or the oil sufficiently contaminated
to warrant an oil change. Ditto for the oil filter.

When I was an apprentice, and later, a rule of thumb, backed by the
vehicle owner manuals, was an oil change every 5,000 km (3,000 mi) with a
filter change every 10,000 km (6,000 mi). This was the norm for the
average 6 cylinder vehicles (GM, Ford, Chrysler) of the day, 4 cylinder
vehicles had more frequent oil changes.

What has happened since then? Oils (and their additives) have improved out
of sight. Also, engine ventilation systems (PCV) have improved vastly.
This has extended the oil change intervals. My car, a Toyota, has the oil
*and* filter change interval *recommended* by the manufacturer at 10,000
km (6,000 mi). So, the oil change interval has been doubled but the oil
filter change interval seems to have remained static.

What seems to have been forgotten here is that the recommended oil change
interval will depend on the use made of the vehicle. If you do a lot of
short runs where the engine never warms up sufficiently, you will
experience greater wear factors and increased oil contamination requiring
shorter than recommended oil change interval. Will that impact the filter
change interval? Maybe. It really depends on the filter capacity - the
point at which the filter will block up and commence bypass. A large
filter of, say, 1 litre (1 quart) capacity might not need to be changed
more frequently. On the other hand, a small filter with half or a quarter
of the capacity might need to have a more frequent change interval.

My Toyota, at 5 years of age and with over 100,000 km clocked up, has
servicing at factory recommended intervals. My wife's car, on the other
hand, has only done 40,000 km in the same time interval. It gets its
servicing, including oil and filter changes, done by *time*. In other
words, it gets an oil change and filter every 6 months *regardless* of
what's on the odometer.


The filter too.
Every day you replace the oil & filter and they won't break down too
much.

But that's not the way the world works.
Instead you follow whatever specs your manufacturer recommends you
follow.

That's why specifications matter. That's why the specs that matter are
usually printed on the oil container.

Manufacturer's specs are a *guide* only. Servicing intervals are dictated
by many variables - there is no hard and fast service interval.

It's not a matter of price or convenience which most others claimed it
was.
It's a matter of knowledge and understanding of meaningful
specifications.

Alls these other people know are dollar bills.
They make all their decisions based only on money.

That's fine.
It works for them.

But I like to make my decisions based on an understanding of the product.
And specs are part of that understanding of the product (for synthetic
oil).

For most laypeople, the specs on, say, the oil, are totally meaningless. I
don't get anal about oil specs. If the oil I buy meets the *minimum* spec
recommended by the car manufacturer, then that's what I go with. No point
in going with a more expensive or more highly speced oil if your engine
cannot benefit from the increased capability.

I am wide open about not knowing how to compare two different synthetics.
At least not yet.

I don't see anyone else here who knows anything about synthetic oil
though.

Everything almost everyone else said they pulled out of their own
assholes.
Especially the ones who claimed it was all about money and not about
specs.

They can't understand what the product is as they only understand money.
Everyone understands money (even me) so it's easy (for them) to decide.

But I like to make my decisions based on meaningfully relevent
specifications which I openly admit I don't know what they are just yet.

I make my decisions based on the car manufacturer's requirements. I figure
they would have a clue about what works in engines they manufacture.

But neither does anyone else (at least not those who have responded).
So I guess I'm on my own.

It's been forty years since I took tribo class,
but at the time there was a standard measurement with a rotating drum
inside
a stationary drum that creates high shear on the test sample. You
measure
viscosity regularly and plot it against time.

Isn't all that supposed to be encompassed meaningfully within the oil
spec?

Why do you get so anal about oil specs?

Thats the way he is, its Arlen Holder with a new nick.

Pick an oil that matches your vehicle manufacturer's minimum spec and
you're good to go.

Clean linear paraffin oils did well on the test, oils with a lot of
crosslinking or rings did poorly.

You'd think a "synthetic oil" base would be pure linear paraffin chains
with a
very narrow range of molecular weights and you might be right or you
might
be terribly wrong, depending. Also, of course, the VI breaks down, not
just
the base oil.

I tried calling both Chevron & Warren Distribution but I'll have to wait
till Monday to get their technical people on the line.

Sometimes they tell us a lot and sometimes they just spit out the
advertising so it's a crap shoot whether or not that call will bear
fruit.

I think the best test so far of the Kirkland synthetic oil was this one.
https://www.youtube.com/watch?v=l9il_piyuT8

And I think the best single description of the (euro) specs is this one.
https://addinol.de/en/products/lubri...pecifications/
If you have something better by all means please let me and all know.