Do short oil changes really clean better?

[OVERKILL]

Not here to argue with anyone. Here to learn or provide my perspective.

I've read numerous articles on the roles of detergent additives. While, yes, one role is to suspend contaminants, acids, etc. to prevent deposits and sludge (prevention being very important), a primary role is to clean surfaces of sludge, varnish, etc. Here are just two quick cites to support my informed belief.

Detergent Additives in Lubricating Oils | CompareMotorOils

These are ingredients of any engine oil as they help the engines by cleaning up the sludge and other deposits (which hinders parts functioning).

comparemotoroils.com

"their first job here is to clean the metal components of the engine in order to make them free of any kind of deposits."

Did you read the line after that?
For example, they are used to clean the contaminants of the carburetor that could otherwise hamper its functioning.

Or the one after that?
Moreover, they are also found to be extremely effective in reducing the deposits of fuel injectors so the pattern of fuel spray does not get affected.

And then:
In addition to cleanliness, they are also used to counterbalance the acids that develop during the combustion of oil (as they have alkaline nature).
That whole article sounds like it was written by AI unfortunately and is conflating detergents in gasoline with those in engine oils.

The only correct statement is the very first one:
The fundamental function of these compounds is to suspend the deposit particles that could later be removed during oil interchange, they also counterbalance the acids that develope during oil ignition.

Which also reads like it was written by AI (oil ignition?! this should read combustion).

Detergent Dispersant is the Most Important Role of Oil Additive

Adding a small amount of other substances to the lubricating material can improve its performance and give it new characteristics. These substances are called oil additives.

www.infomak.com

"main function is to keep the inside of the engine clean, so that the insoluble matter generated is in a colloidal suspension state, and it will not further form carbon deposits, paint film or sludge. Specifically, its role can be divided into four aspects: acid neutralization, solubilization, dispersion and washing.... carbon deposits that have been adsorbed on the surface of the component, and disperse it in the oil to keep the engine and metal surfaces clean."

That article doesn't read much better unfortunately.

These Lubrication Explained videos are pretty decent, here's a screenshot from the 2nd one:

Detergents:


Dispersants:


So, as I described, the detergents prevent these contaminants from plating out on surfaces, keeping them in suspension in the oil. Dispersants work similarly, bonding to the particles, but their main role is preventing agglomeration. Neither is designed to clean-up existing deposits, though dispersants, can, as I noted, work a bit on soft deposits as the oil flows over them.

 

[High Performance Lubricants]

API oils are not formulated to clean, that's not part of any standard. What they ARE formulated to do is keep things clean; not produce significant deposits during regular use, though that may not actually happen depending on the application and usage profile, as the additive package can get overwhelmed and once that happens, so do deposits.

Your typical API oil isn't formulated with anything polar enough to do cleaning. Group II/II+ and Group III/III+ base oils have poor solubility.

Oils contain:
- Dispersants: These prevent the agglomeration of particles that make their way into the oil so that they don't ball together and become heavy enough to fall out of suspension.
- Detergents: These attach to contaminants as they enter the oil, keeping them in suspension and preventing them from plating out on surfaces.

These products are not designed to liberate existing deposits from surfaces, drawing them into the lubricant.

If you have some soft deposits, it's possible that clean oil flowing over that surface could pick-up some of this, but anything that's really "there" like varnish/lacquer/sludge needs to be either dissolved by a solvent, which carries with it some inherent risk, or attacked by something polar, like an ester or AN, which will actively (but slowly) pick apart these deposits and draw them into suspension.

This,

If your oils contains AN’s and or Ester they will clean. Those that do not, do not clean.

 

[ZZman]

This,

If your oils contains AN’s and or Ester they will clean. Those that do not, do not clean.

I assume you believe a slow cleaning process using an additive is the best method.

 

[High Performance Lubricants]

Yes I would choose option 4 on the above list.

I’m not a fan of aggressive attempts to clean or solvents.

If you have ever cleaned engine parts with deposits in a parts washer and realized the amount of effort it takes to remove them, it is easy to be skeptical that we are going to clean something by simply pouring a solvent in the crankcase.

Esters or AN’s will clean. The more you have the faster they clean. Esters can be more economical than AN’s. Circulating these oils will clean gently over time based on the treat rate and now you have controlled cleaning.

These properties are well known.

 

[hardcore302]

I've been known to do 5k changes with a dash of MMO within the last hundred or so miles. Workds for me.