Does Mobil 1 synthetic prevent sludge build up?

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Does the synthetic oil prevent sludge build up in the engine? I was also wondering if the engine does have sludge in it and you were to use mobil 1 synthetic would it desolve or get rid of it? This may be an off topic question on oil.

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Tom F&L GoR

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Prevent sludge build up - yes. Clean up sludge - mostly no.

Here's a little lesson in techno-marketing. Synthetic base oil (i.e. before the additives are added) is *worse* for handling sludge because of the "like dissolves like" rule. Sludge and synthetic base oils are different chemically, and since they don't like each other, they won't dissolve in each other. So the synthetic oil alone won't help clean up sludge.

All oils have dispersants, which are additives to keep sludge from forming in the first place. They basically keep the small scale chemical decomposition products from settling so that they're flushed out during an oil change. That's why a high dispersant oil will turn darker sooner! It's suspending all the crap you don't want to leave behind in the engine.

A synthetic base oil (again, before any additives) is however far less likely to decompose and cause sludge itself, since it has better high temperature properties. But sludge also comes from other decomposition reactions, so in the end, all oils have dispersants anyway. And the role of dispersants is to suspend those nasties - like soot - which is why diesel oils have twice the dispersant treat rates as passenger car oils.

The engine tests that determine the amount of additives are all keep-clean tests; they start with a new engine and see how clean it stays under severe conditions. There is no industry standard clean-up test (mostly because there is no standard way to dirty up an engine.) All those high-mileage oils you see marketed may have more additive, but in most cases the additives are seal swell agents (to soften hardened seals and help prevent leaks) or anti-oxidants (to prevent oil thickening under higher than normal blowby conditions.)

Testing I was part of a few years back showed that highly formulated engine oils do not "clean up" sludged engines during an oil change (maybe slightly over time and many oil changes.) The best protection is still prevention.
 
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