Results of used oil analysis - updated 5/23/11

[Mike]

He's correct. While your used oil analysis has always come back great. I don't think it includes viscosity. Lighter oils don't provide the same level of protection. I run 10w30 year round. My mileage is about 1 mpg less but the oil pressure stays in a more comfortable range with the thicker oil.

[CrackerTeg]

Holy shit! Mike agreed with me?! Is the world ending?

[cna]

What mike said i do the same with good quality oil and hamp oil filter ( "spouse to raise oil pressure by 5psi ") the car feels smooth year round for me I really haven't notice the lack in mpg , having piece of mind is great. I notice my oil has been cleaner every since I switch to Pennzoil ultra over synthetic castrol oil am a wait till my next oil change and get it analyze

[striktlyaccord]

I might try 5w-30 this time then.  Which brand / "high mileage" / extended performance is the question.

[CrackerTeg]

I use standard castrol 10w30 on mine. 120k and still kicking.

[striktlyaccord]

I use standard castrol 10w30 on mine. 120k and still kicking.

10w?  Hmm...

[CrackerTeg]

10w?  Hmm...

Yes sir.

[accordguy04]

Oil question for ya guys (seems like the best thread to put it in... didn't wanna start a new one). 

So I just changed GFs Souls oil (yes I realize the ginger irony lol).  It only takes 3.5 qts and I just buy what's on special at work.  This month was Castrol, last month was Valvoline, all conventional oil.  So now I have 3 qts worth of oil (1 1/2 castrol, 1 1/2 valvoline).  Would it be an extremely horrible/dumb idea to just consolidate it in one jug and use the mixture for an oil change?  Haven't done it yet, just somethin that crossed my mind.

[CrackerTeg]

Generally, I don't because each manufacturer has their own formulas. They may be so insignificant in the different formulas but I try to stick with the same brand per change. It may not make much of a difference but I'm a stickler for consistency when it comes to my oil.

[Mike]

It's a Kia its going to break at a 100,001 miles any way! I wouldnt mix them though....

[accordguy04]

Lol true.

Alright ill just keep switchin up between Valvoline and Castrol and savin the excess in seperate jugs.

[Mike]

Lol true.

Alright ill just keep switchin up between Valvoline and Castrol and savin the excess in seperate jugs.

even 4 changes the sale cycle at AAP should give u the extra to make a full jug of each.

[accordguy04]

Yup.  Just bein cheap since its not my car.

[striktlyaccord]

Here's the response I got from Blackstone Labs regarding my oil change question:

"Truthfully, we don't see a lot of
difference in the wear patterns from switching between different brands or
formulas of oil, especially when an engine has been looking as good as
yours has been in our previous tests. The Mobil 1 5W/20 you've been using
has been holding up very well, and it still had plenty of active additive
left on a long 9,672-mile oil run, so we doubt you'd really see any benefit
from switching to a "high mileage" or "extended performance" type of oil.
Then again, we doubt it would really hurt anything either, so if you'd like
to try it and see if there are any changes, it probably wouldn't do any
harm to experiment with it a little bit.

As for the viscosity, the same thing goes, except you don't want to go too
far out of the engine's comfort zone when it comes to the weight of the
oil. In general, a thicker oil will tend to protect the bearings more,
while a lighter viscosity will have an easier time getting to the upper-end
(pistons/cylinders, etc.), so the viscosity is something of a balancing
act. Go too thick, and the oil won't flow well enough to get to all the
parts of the engine; go too thin, and the oil won't create enough of a film
to stop the metal-on-metal contact in the bearings. If you were having
issues, you might try stepping up or down a grade, just to see if that
helps, but if the engine's been running smoothly on 5W/20 all these years,
and if that's what it's designed to use, then we wouldn't see any reason to
change. If you just went to a 5W/30 or something like that, it probably
wouldn't hurt anything, and we doubt you'd see any problems, but we doubt
you'd see any real benefits, either.

Hope that helps. Maybe once we see a new sample, especially if things do
change with a different type of oil, we'll have more specific advise we can
give you. There are a lot of variables involved in an engine, so it's very
hard to generalize... what works for one, may lead to problems for another,
so the best thing to do is just keep an eye on it, and if you make any
changes, watch carefully to see if there's a difference in the way the
engine runs. Let me know if there's anything else we can do for you. Thanks!"

[striktlyaccord]

The results of my latest used oil analysis finally came in.  This sample had a little over 7,500 miles on it and an oil change interval of about 2 and a quarter years, with a lot of extended periods of sitting without being driven.  The results were still good:

"Time on the oil isn't nearly as important as miles on the oil since oil doesn't really go bad over time.
Modern engines are sealed thoroughly for emissions reasons, so there's no real chance that condensation
or corrosion could enter into the mix. As you can see here, wear metals are very low after 7,581 miles. This
oil could have been left in use, but changing it out didn't hurt anything. The TBN was strong at 2.6 showing
active additive remaining. Less than 1.0 is considered low. Run 9,000 miles on the next oil, even if the car
does see some sitting."

I'm going tp push over 10k between my next oil change as my last oil analysis recommended going even longer, but I changed this sample out at a lower mileage interval since I was concerned with the age of the oil, which apparently didn't affect it much.