Dear BITOG members, a kind hello from the Netherlands and my first post!
In my quest to find the best possible oil for my car I chose the Motul 300V 5W30 (whether the choice was good, is a separate discussion). Before, the car had Audi official dealer oil every year. As the car is a collector' item (how I see it) it didn't drive much but since this year I chose to use more frequently. To evaluate my choice of oil, I invested in a UOA from a respectable Dutch company. Here is my data:
The car:
2008 Audi S5 4.2L V8
29.000 km (oil in) 40.500 km (oil out)
No modifications, 100% original. Exclusively used 98 or 100 octane fuel.
The car is in pristine condition and no expenses are spared to keep it that way. I drive the car weekly and most distances are over >20 km. Occasionally I go for spirited drives and the last 4000 km have been from the Netherlands to Italy and back. The car hasn't (and never will) see track and it goes without saying it is warmed up gently.
The oil:
Motul 300V 5W30
Used for 11.500 km, from February '20 til August '20.
The sample was taken during the oil change. I requested to sample it halfway the 'stream' of oil coming out and collected it in a sterile container.
The oil analysis:
(see attachment). Anyone who can help me out to make it instantly visible?
The conclusions from the UOA:
Positive:
1) Oil TBN is good, no big decline from 7.97 to 6.8 (TAN is 3.58)
2) Viscocity is good, from 11.0 to 11.34, a slight thickening
3) No metals, engine wear nonexistent
Remark:
4) Some silicon might indicate change of air filter is advisable
Worrying:
5) Flash point has dropped significantly from 232°C / 449.6°F down to 160c / 320 F. Presumably due to fuel dillution.
I used this UOA of a virgin 300V 5W40 to compare:
I used the closest resembling car/engine to mine to compare:
Audi S4: https://www.bobistheoilguy.com/forums/threads/05-audi-s4-motul-300v-5w30-5150-oci-67k.174046/
And I used the following to compare:
Honda S2000: https://www.bobistheoilguy.com/forums/threads/motul-300v-5w30-4000-interval-40k-mi-s2000.121468/
Subaru BRZ: https://www.bobistheoilguy.com/forums/threads/motul-300v-5w40-5000km-60000km-odo-subaru-brz.261524/
Looking at my own data first, most seems well, especially for a 11.500 km interval for this oil, underlining its applicability for street use as TBN and viscosity seem in good range. However the flash point is interesting and a bit worrying. Obviously excessive fuel seems the first cause to think of (too rich mixture, leakage?) but I do wonder if there could be an other cause. Also considering that the car did a high speed run to Italy and back, all fuel should have been evaporated if there was any to evaporate. So to me (and I am no expert, I hope you all are) it seems a possiblity that the oil doesn't hold its flash point well enough with my car, my use and my climate... I guess. As mentioned, the car runs perfect and is the same state it left the factory as if it was yesterday. I highly doubt the ECU is overmixing or the lambda is not feeding correct values but I cannot exclude it as a cause either.
So, I am VERY interested in your thoughts!
a) What could be the cause of the significantly lower flash point?
b) What is the cause, of this cause? I.e. if it's fuel dilution, how could it have happened?
c) Any other UOA of Motul 300V that show similar drop in flash point?
d) What would you consider a minimum for the flash point? 200c?
e) Anyone knows of any 4.2L V8's (Audi) UOA and specifically Motul 300V?
e) Other remarks and opinions!
PS. I phone with Motul Germany, technical dept. but they couldn't provide me with an answer. The asked me to mail them the analysis, which I did but I haven't heard back (yet?).
In my quest to find the best possible oil for my car I chose the Motul 300V 5W30 (whether the choice was good, is a separate discussion). Before, the car had Audi official dealer oil every year. As the car is a collector' item (how I see it) it didn't drive much but since this year I chose to use more frequently. To evaluate my choice of oil, I invested in a UOA from a respectable Dutch company. Here is my data:
The car:
2008 Audi S5 4.2L V8
29.000 km (oil in) 40.500 km (oil out)
No modifications, 100% original. Exclusively used 98 or 100 octane fuel.
The car is in pristine condition and no expenses are spared to keep it that way. I drive the car weekly and most distances are over >20 km. Occasionally I go for spirited drives and the last 4000 km have been from the Netherlands to Italy and back. The car hasn't (and never will) see track and it goes without saying it is warmed up gently.
The oil:
Motul 300V 5W30
Used for 11.500 km, from February '20 til August '20.
The sample was taken during the oil change. I requested to sample it halfway the 'stream' of oil coming out and collected it in a sterile container.
The oil analysis:
(see attachment). Anyone who can help me out to make it instantly visible?
The conclusions from the UOA:
Positive:
1) Oil TBN is good, no big decline from 7.97 to 6.8 (TAN is 3.58)
2) Viscocity is good, from 11.0 to 11.34, a slight thickening
3) No metals, engine wear nonexistent
Remark:
4) Some silicon might indicate change of air filter is advisable
Worrying:
5) Flash point has dropped significantly from 232°C / 449.6°F down to 160c / 320 F. Presumably due to fuel dillution.
I used this UOA of a virgin 300V 5W40 to compare:
I used the closest resembling car/engine to mine to compare:
Audi S4: https://www.bobistheoilguy.com/forums/threads/05-audi-s4-motul-300v-5w30-5150-oci-67k.174046/
And I used the following to compare:
Honda S2000: https://www.bobistheoilguy.com/forums/threads/motul-300v-5w30-4000-interval-40k-mi-s2000.121468/
Subaru BRZ: https://www.bobistheoilguy.com/forums/threads/motul-300v-5w40-5000km-60000km-odo-subaru-brz.261524/
Looking at my own data first, most seems well, especially for a 11.500 km interval for this oil, underlining its applicability for street use as TBN and viscosity seem in good range. However the flash point is interesting and a bit worrying. Obviously excessive fuel seems the first cause to think of (too rich mixture, leakage?) but I do wonder if there could be an other cause. Also considering that the car did a high speed run to Italy and back, all fuel should have been evaporated if there was any to evaporate. So to me (and I am no expert, I hope you all are) it seems a possiblity that the oil doesn't hold its flash point well enough with my car, my use and my climate... I guess. As mentioned, the car runs perfect and is the same state it left the factory as if it was yesterday. I highly doubt the ECU is overmixing or the lambda is not feeding correct values but I cannot exclude it as a cause either.
So, I am VERY interested in your thoughts!
a) What could be the cause of the significantly lower flash point?
b) What is the cause, of this cause? I.e. if it's fuel dilution, how could it have happened?
c) Any other UOA of Motul 300V that show similar drop in flash point?
d) What would you consider a minimum for the flash point? 200c?
e) Anyone knows of any 4.2L V8's (Audi) UOA and specifically Motul 300V?
e) Other remarks and opinions!
PS. I phone with Motul Germany, technical dept. but they couldn't provide me with an answer. The asked me to mail them the analysis, which I did but I haven't heard back (yet?).
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