Originally Posted By: 2015_PSD
Originally Posted By: WellOiled
Originally Posted By: 2015_PSD
I have not owned a GM vehicle since 2003 (and doubt that I ever will again), but are you guys suggesting that a non-Dexos SM or SN oil ran for a
reasonable OCI would generate this carbon whereas a Dexos oil would not? Paint me a serious skeptic on that one--have engine designs changed
that much and likewise has oil improved that much since the pre-Dexos days (2010)?
The topic engine is direct injection. GM developed the DEXOS 1 spec to address deposit formation and cleanup primarily for DI and turbo engines. The maintenance history is unknown. We know that DI engines generate more soot that can lead to more carbon deposits.
I agree that DI engines can generate more carbon, but (obviously) we are not talking about a diesel. I would question whether or not it would be the same with a Dexos oil (especially with the unknown OCI/maintenance history)--i.e. is Dexos that much better than a standard SM or SN oil?
I suspect the maintenance was sub par and has little to do with what oil was used. However, a DEXOS oil addresses many issues GM was having with their more recent engines.
This link summarizes DEXOS 1 objectives:
Dexos 1
These points seem important to me:
1. "The result is a high performance fluid providing significant wear protection,
improved piston cleanliness, a
reduction in volatility and oil consumption, enhanced aeration control for improved fuel efficiency, and
better oxidation properties."
2. "The most current dexos1™ specification (dexos1™ Gen 2) was released in 2015 to provide even higher engine performance and protection,
particularly low speed pre-ignition (LSPI) protection in small displacement turbo-charged engines. dexos1™ Gen 2 is the best option for your GM spark-ignited gasoline engine regardless of make, model or year. The GMW numbers in the table below apply to dexos® specifications."
I think most of the DEXOS oils are at least blends or full synthetics.