Quote:
Originally Posted by JHZR2
Given that LL-4/low SAPS oils are hitting the market in the USA, Id advise to beware of this.
Low SAPS oils, such as LL-4, MB 229.51 and VW 504/507 are suitable for use in diesel engines in the USA because of the low sulfur content of the fuel. However, in the USA, gasoline has a higher sulfur content.
The low SAPS oils have lower starting TBN and poorer TBN retention due to additive chemistry. Not an issue with ULSD, but it is an issue in gas engines running higher sulfur fuels without lean stratified charge DI, which is used (at least in some cases) in Europe where the NOx emissions regulations are not as stringent.
The outcome as a result is that the acid buffering capability used in gas engines in the USA gets used up far faster than the notional design approach intended. This can allow much more substantial corrosion and related issues, unless monitored closely by UOA for TBN and sulfation.
LL-4 vs LL-1 isn't about being more expensive, and if you look at the specifics of the BMW spec, there isn't much difference other than that LL-1 is based upon ACEA A3/B4 while LL-4 is based upon ACEA C3.
I would not run low SAPS oils in North American gas engines. I have run the UOAs and studied the chemistry performance myself. Wear performance of the additives in the low SAPS oils is just fine, so long as TBN is retained. But without active monitoring, its a crapshoot.
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I wasn't saying to buy LL4 oil for use in the USA. I have a US spec car here in Germany, and I use German fuel(low sulfur) so I use a LL4 oil.
In the USA I would use only a LL1 approved oil.
