Ever have a car oil clean for long time?

[ezbtr]

Was just talking to a buddy, my 06 Mustang GT 4.6 V8 (mint 5 spd AUTO) even after 3-4K oil was still clean! Sold at 72K. Anyone else? I Loved that car but "NEEDED" the 5.0!!!!!! (2017 for a year then the 2020 gt lowered pro suspension (5K in parts alone), Shelby wheels, 305s in the back, 460 hp 10 spd auto now

 

[Lpgc]

I know of lots of cars that have clean engine oil for a long time and a lot of miles after an oil change. I convert vehicles to run on LPG (propane) which burns a lot cleaner than petrol (gasoline), running on LPG there's no fuel wash of oil from cylinder bores, no liquid fuel to get past rings to dilute the oil and much less carbon getting past rings into oil. Oil stays looking yellow and clean for thousands of miles. Similar story with piston crowns etc, no carbon build up and even if an engine has some carbon build up after running on petrol running on LPG for a few thousand miles will see it clear up.

I've converted the old Windsor 5.0, 4.6 and later 5.0 Mustangs, same story all engines.

 

[Pmt133]

Not that it's really a function or indication of how well used the oil is or anything (color). But my 19 running 6.5-7.5k oil change intervals more or less comes out a shade or two darker than it goes in. So from honey to more fresh maple syrup?

 

[Ifishmuskie2]

It seems like once you get 60,000 miles on them the oil is darker. After that I change the oil at 3,000 miles of use just to get more of the dark oil out.
I’ve never tried seafoam in the oil. That might be a good way to get more of the sludge out.

 

[bajaman123]

MANY factors contribute to the COLOR of the oil...if that is what you are basing your opinion on "clean" about. One certainly should never imply that the lack of coloring in the oil is relevant to absence of contaminants, acids, etc.

 

[Pmt133]

MANY factors contribute to the COLOR of the oil...if that is what you are basing your opinion on "clean" about. One certainly should never imply that the lack of coloring in the oil is relevant to absence of contaminants, acids, etc.

We measure color in our lab as a purely esthetic property. The GC mass spec and other ancillary equipment is for everything else that actually matters.

 

[Lpgc]

We measure color in our lab as a purely esthetic property. The GC mass spec and other ancillary equipment is for everything else that actually matters.

For sure colour doesn't matter.

Depending on what the tests look for, maybe anything that causes a change in colour would be identified in the tests your lab does even without noting the colour?

But it seems to me that colour does seem to be telling of at least something that does matter, which is the amount of carbon and/or blowby?

If you knew a particular model engine had moly top rings but didn't find any moly in the oil, then one reason for the lack of moly could be that the rings hadn't worn or another reason could be that the rings had worn or been overheated to such extent there was hardly any pressure on the cylinder walls / blowby and lack of compression.

I am interested in what info can be gained from oil analysis tests.

 

[Scott Danforth]

Oooh another oil thread

 

[Pmt133]

For sure colour doesn't matter.

Depending on what the tests look for, maybe anything that causes a change in colour would be identified in the tests your lab does even without noting the colour?

But it seems to me that colour does seem to be telling of at least something that does matter, which is the amount of carbon and/or blowby?

If you knew a particular model engine had moly top rings but didn't find any moly in the oil, then one reason for the lack of moly could be that the rings hadn't worn or another reason could be that the rings had worn or been overheated to such extent there was hardly any pressure on the cylinder walls / blowby and lack of compression.

I am interested in what info can be gained from oil analysis tests.

It's not always a 1:1. We lab a litte different because we aren't dealing with oil, and thus are not terribly concerned with color. It takes very little to color oil over an oci and I think most people would be surprised at that. If your gas engine has oil coming out looking like a diesel, there for sure are other issues at play that need to be investigated. But an oil analysis very well may not show you what is coloring it. GC mass spec and other equipment has a much harder time with particles in visible spectrum. If you see metal shavings in your oil, an oil analysis may very well come back looking "normal"

An oil analysis is only useful if you have a complete history of the engine established with samples, then you can determine if there is a significant difference between changes. Otherwise and in most cases, you are sampling to establish the trend.