Why some oil stays cleaner longer (?)

[fdcg27]

As many have noted, darker oil does not equate with dirtier.
As some have noted, some oils start out very light in color, so they may appear to darken less with use.
The only way to determine how loaded an oil is with contaminants with some precision would be to UOA it.
There's also the blotter test, which at least one well respected member endorses and some cars use opacity sensors as part of their intellignet OLM system.
You can't equate color with cleanliness in any oil in service.

 

[demarpaint]

All things being equal IMO an oil that stays cleaner longer is either cleaning less, or has less to clean. I'd say its pretty hard to tell while oil is in actual service. The only way to tell which oils are cleaning better is in a controlled test environment, or visual tear down and inspections.

 

[bigt61]

Originally Posted By: demarpaint
All things being equal IMO an oil that stays cleaner longer is either cleaning less, or has less to clean.


+1

 

[Trav]

I believe thats correct Frank, it has less to clean.

This is one of my engines, the engine is low mileage, old and never been torn down.
The whole inside of this engine looked like the piston seen at the top of the picture, no additives have ever been used just a high quality synthetic oil for a while now but not a lot of miles.

Interestingly with the first oil changes the oil had a distinct dark red color almost like ATF.
As time went by the red color decreased significantly and under the valve cover is now spotless. This is with the pan off, 5 pistons are almost clean (like the one in the lower right) and the one being blocked by the oil pickup tube is getting better albeit slower.

The crank is spotless as is behind the timing cover and camshaft, in the picture you can see the oil has a red tint to it.
Just a guess but i believe when the red color stops completely the last of the varnish from the bottom of the pistons will be gone also.

I wont answer questions about how the engine got this way (i know the whole history of this engine) or what oil i am using, from past experience this board gets too argumentative and some posters/fan boys get carried away with their opinion of why it cant be or shouldn't be and god knows what else.
This will be the only pan off shot of this engine, it will never be removed again barring some sort of accident or rebuild.

The compression is perfect higher end of OEM new spec on all 6 with less then 2lb difference, initially there was over 35lb. No oil leaks.

The conclusions i draw from this are..
Full synthetic oil can clean up a dirty engine, if it can clean it it can certainly keep it clean.
It needs no extra OTC additives to perform this.
It can and will restore compression by freeing up the rings and keep them clean. Ditto lifters and lash adjusters.
It does not cause leaks on an engine that didn't have one in the first place, even on this old timer.

Why would you want to use or need an additive? Simple, for the synthetic oil to perform this little cleaning miracle it takes a long time, apparently not miles as this car only sees 3K or less a year, this year only 200 miles.
In my case it doesn't matter as the car isn't going anywhere until i get sick of it, which may be 10 more years or more.
There are additives that will restore compression in a very short time and others that will help clean the engine much quicker than this, however non will do it in a few weeks or months.

 

[demarpaint]

Originally Posted By: Trav


Why would you want to use or need an additive? Simple, for the synthetic oil to perform this little cleaning miracle it takes a long time, apparently not miles as this car only sees 3K or less a year, this year only 200 miles.
In my case it doesn't matter as the car isn't going anywhere until i get sick of it, which may be 10 more years or more.
There are additives that will restore compression in a very short time and others that will help clean the engine much quicker than this, however non will do it in a few weeks or months.

Good point Paul. It could take years to clean an engine with synthetic oil all by itself. Many of us don't have the time or the patience to wait. Judging by the pictures it was more varnish than anything else you were looking to clean, and varnish can be a royal PITA to clean. You're spot on about the color observation too, varnish turns oil a redish [sp] brown color and lightens up and takes longer to discolor oil as it gradually comes off OCI after OCI. A dedicated cleaning product can clean it up faster, but for the amount of miles you log yearly it would still take a very long time, and quite honestly I'd also opt out of using it.

I also believe that varnish is built up in layers, or coats, and is removed the same way. Varnish can also make for a great foundation for sludge to attach itself to.

 

[TrevorS]

Interesting but back onto the topic of oil color, any thoughts on whether the linked article might apply to motor vehicles?

http://www.machinerylubrication.com/Read/84/oil-color-test

 

[TrevorS]

And here is an interesting video on oil color and change intervals

 

[y_p_w]

Originally Posted By: TrevorS
And here is an interesting video on oil color and change intervals


And once you get down to the comments, there are tons of people saying they're crazy and you still have to change every 3000 miles.