Soot loading vs. oil brand, viscosity, etc.

[chuntag95]

I'm just wondering if anyone has seen a difference when you have changed oil brands, viscosities or dino to synthetic? I changed from a 15W40 Synthetic to a 5W40 Synthetic and it sure seems like it got "dirtier" much faster. I don't have oil analysis on both at similar mileage, it is more of a visual. Anyone else or have I sniffed to many diesel fumes from filter and lift pump installs? [img]tongue.gif[/img]

[Bullseye54]

I just changed my first batch of 5w40 Rotella Synthetic,& it was BLACK.Had 6000mi mostly towing on it.After this batch of Rotella Synthetic I'm going to Amsoil 15w40.

[chuntag95]

Let me know what happens. I changed from Amsoil to the Delvac and saw it get darker much quicker. I think I am going to change again and see if it repeats.

[ratlover]

I believe that only the percent of soot an oil can handle changes with brands. Soot level remains the same but the oils ability to deal with it will alter. But I'm sure someone will tell me I'm full of it

[chuntag95]

So which would be better, one that get's darker quicker or slower?

[Gbenzx01]

chuntag95,

you are describing exactly what I want my oil todo.
We use Delvac 1 in several diesel engines & assuming filter is new we want it to turn black asap = the oils ability to suspend particle matter. No expert here but if the oil is staying to clean then we question it's ability to do it's job.
We change filters every 3k miles to get the big stuff & lab tests show that the Delvac is still floating the dust in some cases at 12k miles.
George may know for sure but we were told by Cummins Southeast recently that there are otr trucks running the road 100k miles before changes with syn oils. Don't know if Mobil is one of these oils or not.
It seems like such a waste to me anyway to see people throw this remarkable oil away just because it has 2-3k miles accumalated.

Now chuntag,
my question for you, did you explore the possibility of reducing the engine temp a little with thermostat to help keep Allison cooler or could it even be done w/o upsetting the computer?
Not having a prob with ours just looking for long term stay power.

Thanx, Gben

[a64pilot]

JMHO,
An oil that turns black quickly is the better oil, not scientific I know, but my belief is that it's additive package is doing what it is designed to do.
Now, what would be intersting would be to see if it turned as black as quickly on the second change. If it didn't it would imply that it cleaned up soot that the original oil had left in the engine