As I pointed out already, your VOA for FSx2 5w-40 (traditional high ca euro blend) is wildly different from the topic oil, which is FS 5w-40 API SP rated.
Mobil1 Euro FS 5w-40 API SP / 5120 mi. / 2018 Buick Tour-X 2.0 TGDI
- Thread starter 92saturnsl2
- Start date
TiGeo
$50 site donor 2024
Ah. Nevermind.
- Joined
- Sep 15, 2023
- Messages
- 12
A flash point of 435°F is not indicative of fuel dilution. The flash point for M1 FS 5W-40 SP is 465°F according to Mobil's website - ASTM D92 (not D93). Usually, a sub-400°F flash point is a good indicator of fuel dilution. This begs the question: what can't Blackstone Labs measure accurately? Is it the flash point, the viscosity at 100°C, or both?
TiGeo
$50 site donor 2024
Any other band that apparently sheared this much would be trashed but M1? "Looks great" from the crowd. Starting viscosity would be 13+ I beat the crap out of my car and with some fuel most of the other Euro 5W40 oils I ran would end in the 11s.
- Joined
- Sep 15, 2023
- Messages
- 12
I believe it's just a fluke in how Blackstone Labs measured the operating temperature viscosity. Mobil 1 FS 0W-40, 5W-30, 5W-40, and 5W-50 all use comb polymers as Viscosity Index Improvers and start with thicker base oils than previous formulations in the Full SAPS lineup.
If anyone spends any amount of time reading the latest ExxonMobil patents, they will soon realize how advanced their most recent API SP formulations are. I believe the word most commonly used on automotive forums to describe such motor oils is "stout."
To make a long story short: no, I do not believe the OP's motor oil sheared. I believe that Blackstone Labs made a mistake. Having the sample retested would absolutely clarify that.
If anyone spends any amount of time reading the latest ExxonMobil patents, they will soon realize how advanced their most recent API SP formulations are. I believe the word most commonly used on automotive forums to describe such motor oils is "stout."
To make a long story short: no, I do not believe the OP's motor oil sheared. I believe that Blackstone Labs made a mistake. Having the sample retested would absolutely clarify that.
Yes.
Blackstone is not much good for fuel dilution although you can guess somewhat from viscosity and flash point. If both are very low for grade there is a good chance it's fuel.
Blackstone does seem to be pretty good at viscosity though, recently the same OCI was tested by three different labs and all of them were within a few tenths of each other.
Blackstone does seem to be pretty good at viscosity though, recently the same OCI was tested by three different labs and all of them were within a few tenths of each other.
- Joined
- Sep 15, 2023
- Messages
- 12
I'd probably use Wearcheck or Polaris and call it a day. 435F isn't a low flash point by any means for a 5W-40. I've looked at many reports here and on other forums, and most of the time when I see fuel dilution, I also see a sub 400F flash point. I don't think the OP has anything to worry about, Mobil 1 FS 5W-40 is a very capable and well engineered motor oil.
TiGeo
$50 site donor 2024
I'd say BS is at least consistent or precise even if they aren't accurate. Think about that bullseye figure from science class. I've had lots of BS UOAs and they seem to be reasonable w/r to flashpoint/viscosity/fuel even if the absolute numbers aren't correct. Lower FPs = lower viscosities = more fuel on the UOAs I've had done. Here, yeah, the FP is a bit high and I missed that in my comment above...most of my xW40 results with ~10cST ending viscosities have sub-400 FPs but typically still show the classic BS "<0.5%" fuel value.
