Why some oil stays cleaner longer (?)

[Mark72]

I have noticed a lot of people will say X brand of oil stays cleaner and more clear than Y brand of oil. Because fuel byproducts do make their way into the crank case, is it possible that the oils that stay clean longer are better because they allow the engine to run more efficiently causing a better burn of the gasoline which allows the oil to stay cleaner? Or is way off and totally unrelated?

 

[SatinSilver]

 

[Merkava_4]

What keeps your oil clean is the oil filter, air filter, and a good operating crankcase ventilation system.

 

[SrDriver]

I guess if the oil is not doing its job cleaning the engine and allowing stuff building up in the engine rather than removing it that would cause the oil to be cleaner?

Changing brands of oil may remove this buildup and darken faster?

 

[Mark72]

Then why do some oils darken faster than others in not only my vehicle but many others who use the same filter but differnet brand on occassion?

 

[Quattro Pete]

Originally Posted By: Mark72
Then why do some oils darken faster than others in not only my vehicle but many others who use the same filter but differnet brand on occassion?

The way I understand it, some additive packs turn darker when subject to heat. It doesn't mean they're bad. That's just chemistry and may be normal.

 

[Brybo86]

I'm not really sure about brand to brand differences but I think there is definitely a difference between a synthetic and a dino...

with syn in my car it will typically start to noticeably darken in about 7500 miles
dino used to darken by about 4000 miles

 

[djb]

Even if the oil "helped the engine run more efficiently" by eliminating all internal friction, that would only have a minor effect on combustion product generation.

Most of the inefficiency isn't friction of the lubricated parts. It's thermodynamic losses. Pretty much unavoidable when you try to extract energy in only milliseconds before throwing out the gasses and starting over.

 

[SteveSRT8]

Originally Posted By: djb

Even if the oil "helped the engine run more efficiently" by eliminating all internal friction, that would only have a minor effect on combustion product generation.

Most of the inefficiency isn't friction of the lubricated parts. It's thermodynamic losses. Pretty much unavoidable when you try to extract energy in only milliseconds before throwing out the gasses and starting over.


Excellent point and one of my fav subjects.

There are more ways than just a turbine or a heat exchanger to recover the heat energy wasted!

 

[skyactiv]

If you want your oil to look clean longer, buy some API SA 30W at a dollar store.

 

[y_p_w]

What does it mean to "stay cleaner longer"? Most people have no way of quantifying that short of an oil analysis. Color doesn't really tell anything. And motor oil contains detergents and dispersants which allow it to operate properly with assorted stuff in suspension.

 

[gregk24]

Probably just different additives used by different companies. Some may darken more or less when subjected to heat. Even though many say its not a problem I still like my oil to look clean.

 

[nleksan]

I have yet to find, personally, any correlation between the color of the oil and the condition of the engine, excluding known sludged motors.

I knowa llot of people who go by oil color as a change indicator, and I have worked with three of them building up at least the top end of the motor, and while these are part time track cars, they still all showed more wear than what would be considered acceptable for the mileage (by me).

So, unless it turns black and chunky, I would not worry about it...

 

[Errtt]

Seems to me a oil with stronger detergent pack would turn darker sooner than an oil with less detergents... all else the same.
Look at Pennzoil site Pennzoil conventional vs PU regards to cleaning.
The one that cleans more would seem to darken sooner.
Like cleaning something with water & detergents / detergent dose and/or detergent type

 

[y_p_w]

Originally Posted By: Errtt
Seems to me a oil with stronger detergent pack would turn darker sooner than an oil with less detergents... all else the same.
Look at Pennzoil site Pennzoil conventional vs PU regards to cleaning.
The one that cleans more would seem to darken sooner.
Like cleaning something with water & detergents / detergent dose and/or detergent type

Only if there's something in there that wasn't adequately cleaned out by previous detergent oil. Most darkening isn't an issue. It gets darker over time, and it's motor oil doing part of what it's supposed to do, which is suspend stuff in the oil rather than allowing it to clump in the engine.

 

[TrevorS]

Soot apparently varies in size from 0.3 to 39 microns in size.

So filter efficiency will be a factor in how quickly oil gets dark.

 

[donnyj08]

i think original color has a little to do with how fast it turns a darker color.

Pennzoil Conventional comes out of the bottle very yellow/goldish while Valvoline conventional comes out a lot more clear. ive always noticed Pennzoil Conventional to look darker than Valvoline conventional at 5k miles in my company car. i believe it is because Pennzoil Conventional is darker to begin with.

Motorcraft is probably the clearest looking oil ive seen when new. it also takes a long time for it to become dark. i think it's because it is such a light almost clear color to begin with

i do not think if a oil stays lighter that it is not cleaning. I've seen many engines that ran Valvoline conventional and motorcraft two very light tinted oils that have kept engines spotless inside on reasonable intervals.

 

[crazyoildude]

if an oil turns dark faster it is cleaning better...

 

[Clevy]

Originally Posted By: gregk24
Probably just different additives used by different companies. Some may darken more or less when subjected to heat. Even though many say its not a problem I still like my oil to look clean.


I agree with the part about different additive packages potentially darkening at different rates and the add pack is the likely culprit as to how fast an oil blackens.
For example in my experience using Mobil 1 5w-20 in a known spotless engine the oil went black very quickly compared to the Quaker State Ultimate Durability 5w-20 the engine was using before.
I doubt that the rate of oil blackening has any negative impact on its performance in a known clean engine.
Food for thought........
In summertime warm weather operation would a 10w contribute to a better ring seal than a 0w until the engine reaches operating temp and if so can that contribute to less combustion by-products being absorbed by the oil during the warm up phase and thus the oil may darken less over an identical time period.
Or is that a non issue even during the hotter summer months?
I know that using an oil that's a 10w vs a 0w can help oil consumption and burning at start up from seeing older cars that burn oil visibly as indicated by the exhaust and can going thicker on the front number help an oil last longer in service by lowering blow-by at start up and during warm up.

Thanks in advance for any insight

 

[Clevy]

Originally Posted By: crazyoildude
if an oil turns dark faster it is cleaning better...



Is this serious?