Sludge

[Dale_Knight]

Are some types of oils; group II based, group III based or PAO based, or some specific manufacturers oils although rated SL or SM more prone to sludging, or is sludging more of an engine problem irregardless of the oil manufacturer or base oil type, assuming that the correct grade and oil specification for the engine is used.

http://www.autosafety.org/getcat.php?cid=28

http://www.schleeter.com/oil-sludge.htm#synthetic

 

[Gary Allan]

It's a combo of obscure oil spec's and engine design and lack of wide spread availability of select oils ..and the lack of use of them.

My opinion:

Toyota: poor design. The flag ship of the 3rd world rated auto can't figure out how to cope with America when they mastered it for a long time.

Audi/VW/etc.: silly anal exclusive oils that were only available from the dealer ..and the thieving dealer probably didn't use them either. Too long drain intervals and consumers that probably didn't go back to the dealer even if it was free due to not enough of them being around to make it convenient. This is apparent due to the long list of suffixes on their spec's and the rapid rate that they occurred. They only THOUGHT that they were that smart.

Another manufacturer that didn't "buffer" for the American public (small sumps blahablahblah) ..yet made great efforts to put their cars within their hands...

Chrysler (any American design w/issues): Standard routine for stuff that's thrown together with deadlines that, if not met, cost more in lost production than they do in warranty. Ford is another one with a multitude of head cracking engines (take your pick of issue of choice ...be it sludge or whatever). The engineers who design these problem things typically get promoted since they enabled production deadlines to be met .and kept the trains on time. Can't lose that quarterly profit number for the herding masses that are (were) flocking to spend their nickels (formerly) on your latest offering.

 

[JAG]

Yeah it's a combination.

Every oil has a different ability to resist sludging, even within any given oil specification. API SL or SM are so "low-bar" that the difference between an oil that squeaked by the testing and some of the best oils that also passed the tests is large. The more rigorous specs out there decrease that gap between the "squeakers" and the best of the bunch.

Every engine has a different propensity to cause sludging.

 

[Gary Allan]

Yes, when there's a PASS:FAIL test ..just like citizens ..some can be more equal than others

 

[Dale_Knight]

Thanks fellows, any opinions as to if a low SAPS extented drainage automobile oil would have less or more propensity to sludging in severe service compared to an API SM mid-SAPS similarly extended drainage rated oil in the same engine or compared to a similar but API SL oil.

 

[JAG]

That's a hard question. I'll try to research that tomorrow but for now will post an old thread on Low SAPS oil formulation you may find interesting: https://bobistheoilguy.com/forums/threads/formulating-a-low-saps-oil.74440/

 

[Dale_Knight]

Thanks JAG, not that I have a lot of really good automobile low SAPS oil choices in Canada; there may be some overpriced low SAPS oils at some of the Euro dealers parts desks although I haven't checked that yet and ELF Total looks to be supplying a couple of the Quartz Ineo marks here plus some shipping from wherever it's stocked, Ontario I think. BP Castrol Edge low SAPS are still reserved for Europe I think unless dealers can get it here and PetroCanada hasn't done anything as far as I can tell from their net info. Cool thing about some of the Euro spec low SAPS is that some are HTHS > 3.5, so they may work in a new Nissan engine until it starts getting 200K mile sloppy.