2008 V8 vantage oil choice
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I did a ton of reading recently and thought I would put in a note on this thread to help other owners who wonder.
ACEA A3/B3 (superseded by B4) is met by a few of the thicker 30 weight oils and almost all the 40s, the reason being the HTHS requirement of 3.5cP is correlated to the 100C viscosity. It seems like Aston Martin spec'd 10W-60 so that the oil can run at high temperature for a long oil change interval, so the HTHS figure is perhaps the most important one as the operating conditions where the film strength is an issue are at high temps well over 100C.
Looking at a bunch of UOAs and discussions, it seems that 10W-60 and 5W-50 are both grades that have a lot of viscosity index improvers and as a result shear very quickly. At 100C, the usual Castrol/M1/Shell 10W-60s start out life in the ~22 cSt range and shear down to 17 within like 2000 miles in Mustangs and BMWs, while 5W-50s start out around 18cSt and shear down to the 13-14 cSt range in a similar amount of time. The HTHS for a 10w-60 starts usually around 5.2 cP, M1 5w-50 is 4.4 cP, M1 15W-50 is 4.5 cP, and Castrol 5w-50 is 4.1 cP. All of them except the 15W-50 probably see that number drop over time.
If I understand correctly, the oils with less VII like 5w-40, 10w-40, 15w-50 shear less, and ester base oils like Motul 300V (not 8100) and Redline are also much more shear resistant and have higher HTHS. For example, Redline 0W-40 has an HTHS of 4.0cP (higher than Mobil1 0W-50 and almost higher than Castrol 5W-50), Redline 5W-40 has a HTHS of 4.4cP (equal to Mobil1 5W-50).
Therefore...if you run a thicker 40 with high HTHS like M1 or Redline 5W-40, you would have something just as thick or thicker than Castrol 5W-50 with a few thousand miles on it. If you run M1 or Castrol 5W-50, the 100C viscosity drops down to what fresh 5W-40 is pretty quickly, so for a car that's not driven much, not driven at the track, and gets its oil changed well before 10k miles (probably most of the cars here), it seems to me that going with a thick 40 with high HTHS shouldn't be a problem. By contrast, for something with a lot of track use, something thick might let you get away with changing the oil infrequently.
M1 0W-40 on the other hand would make me uncomfortable for a long oil change interval as it's right at 3.5cP HTHS and shears more than the 5w or 10w.
ACEA A3/B3 (superseded by B4) is met by a few of the thicker 30 weight oils and almost all the 40s, the reason being the HTHS requirement of 3.5cP is correlated to the 100C viscosity. It seems like Aston Martin spec'd 10W-60 so that the oil can run at high temperature for a long oil change interval, so the HTHS figure is perhaps the most important one as the operating conditions where the film strength is an issue are at high temps well over 100C.
Looking at a bunch of UOAs and discussions, it seems that 10W-60 and 5W-50 are both grades that have a lot of viscosity index improvers and as a result shear very quickly. At 100C, the usual Castrol/M1/Shell 10W-60s start out life in the ~22 cSt range and shear down to 17 within like 2000 miles in Mustangs and BMWs, while 5W-50s start out around 18cSt and shear down to the 13-14 cSt range in a similar amount of time. The HTHS for a 10w-60 starts usually around 5.2 cP, M1 5w-50 is 4.4 cP, M1 15W-50 is 4.5 cP, and Castrol 5w-50 is 4.1 cP. All of them except the 15W-50 probably see that number drop over time.
If I understand correctly, the oils with less VII like 5w-40, 10w-40, 15w-50 shear less, and ester base oils like Motul 300V (not 8100) and Redline are also much more shear resistant and have higher HTHS. For example, Redline 0W-40 has an HTHS of 4.0cP (higher than Mobil1 0W-50 and almost higher than Castrol 5W-50), Redline 5W-40 has a HTHS of 4.4cP (equal to Mobil1 5W-50).
Therefore...if you run a thicker 40 with high HTHS like M1 or Redline 5W-40, you would have something just as thick or thicker than Castrol 5W-50 with a few thousand miles on it. If you run M1 or Castrol 5W-50, the 100C viscosity drops down to what fresh 5W-40 is pretty quickly, so for a car that's not driven much, not driven at the track, and gets its oil changed well before 10k miles (probably most of the cars here), it seems to me that going with a thick 40 with high HTHS shouldn't be a problem. By contrast, for something with a lot of track use, something thick might let you get away with changing the oil infrequently.
M1 0W-40 on the other hand would make me uncomfortable for a long oil change interval as it's right at 3.5cP HTHS and shears more than the 5w or 10w.
Last edited by convexproblem; Apr 27, 2021 at 02:18 AM.
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I did a ton of reading recently and thought I would put in a note on this thread to help other owners who wonder.
ACEA A3/B3 (superseded by B4) is met by a few of the thicker 30 weight oils and almost all the 40s, the reason being the HTHS requirement of 3.5cP is correlated to the 100C viscosity. It seems like Aston Martin spec'd 10W-60 so that the oil can run at high temperature for a long oil change interval, so the HTHS figure is perhaps the most important one as the operating conditions where the film strength is an issue are at high temps well over 100C.
Looking at a bunch of UOAs and discussions, it seems that 10W-60 and 5W-50 are both grades that have a lot of viscosity index improvers and as a result shear very quickly. At 100C, the usual Castrol/M1/Shell 10W-60s start out life in the ~22 cSt range and shear down to 17 within like 2000 miles in Mustangs and BMWs, while 5W-50s start out around 18cSt and shear down to the 13-14 cSt range in a similar amount of time. The HTHS for a 10w-60 starts usually around 5.2 cP, M1 5w-50 is 4.4 cP, M1 15W-50 is 4.5 cP, and Castrol 5w-50 is 4.1 cP. All of them except the 15W-50 probably see that number drop over time.
If I understand correctly, the oils with less VII like 5w-40, 10w-40, 15w-50 shear less, and ester base oils like Motul 300V (not 8100) and Redline are also much more shear resistant and have higher HTHS. For example, Redline 0W-40 has an HTHS of 4.0cP (higher than Mobil1 0W-50 and almost higher than Castrol 5W-50), Redline 5W-40 has a HTHS of 4.4cP (equal to Mobil1 5W-50).
Therefore...if you run a thicker 40 with high HTHS like M1 or Redline 5W-40, you would have something just as thick or thicker than Castrol 5W-50 with a few thousand miles on it. If you run M1 or Castrol 5W-50, the 100C viscosity drops down to what fresh 5W-40 is pretty quickly, so for a car that's not driven much, not driven at the track, and gets its oil changed well before 10k miles (probably most of the cars here), it seems to me that going with a thick 40 with high HTHS shouldn't be a problem. By contrast, for something with a lot of track use, something thick might let you get away with changing the oil infrequently.
M1 0W-40 on the other hand would make me uncomfortable for a long oil change interval as it's right at 3.5cP HTHS and shears more than the 5w or 10w.
ACEA A3/B3 (superseded by B4) is met by a few of the thicker 30 weight oils and almost all the 40s, the reason being the HTHS requirement of 3.5cP is correlated to the 100C viscosity. It seems like Aston Martin spec'd 10W-60 so that the oil can run at high temperature for a long oil change interval, so the HTHS figure is perhaps the most important one as the operating conditions where the film strength is an issue are at high temps well over 100C.
Looking at a bunch of UOAs and discussions, it seems that 10W-60 and 5W-50 are both grades that have a lot of viscosity index improvers and as a result shear very quickly. At 100C, the usual Castrol/M1/Shell 10W-60s start out life in the ~22 cSt range and shear down to 17 within like 2000 miles in Mustangs and BMWs, while 5W-50s start out around 18cSt and shear down to the 13-14 cSt range in a similar amount of time. The HTHS for a 10w-60 starts usually around 5.2 cP, M1 5w-50 is 4.4 cP, M1 15W-50 is 4.5 cP, and Castrol 5w-50 is 4.1 cP. All of them except the 15W-50 probably see that number drop over time.
If I understand correctly, the oils with less VII like 5w-40, 10w-40, 15w-50 shear less, and ester base oils like Motul 300V (not 8100) and Redline are also much more shear resistant and have higher HTHS. For example, Redline 0W-40 has an HTHS of 4.0cP (higher than Mobil1 0W-50 and almost higher than Castrol 5W-50), Redline 5W-40 has a HTHS of 4.4cP (equal to Mobil1 5W-50).
Therefore...if you run a thicker 40 with high HTHS like M1 or Redline 5W-40, you would have something just as thick or thicker than Castrol 5W-50 with a few thousand miles on it. If you run M1 or Castrol 5W-50, the 100C viscosity drops down to what fresh 5W-40 is pretty quickly, so for a car that's not driven much, not driven at the track, and gets its oil changed well before 10k miles (probably most of the cars here), it seems to me that going with a thick 40 with high HTHS shouldn't be a problem. By contrast, for something with a lot of track use, something thick might let you get away with changing the oil infrequently.
M1 0W-40 on the other hand would make me uncomfortable for a long oil change interval as it's right at 3.5cP HTHS and shears more than the 5w or 10w.
I use Motul or LM 10W60 synthetic and change it annually.
Last edited by MRCW; Apr 27, 2021 at 05:09 AM.
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If you're in a pinch, liquimoly 10-60 is usually in stock at Napa stores. I just go with the most cost effective 10-60 which has been LM until now. I just got a good deal on Motul so my next two oil changes will use this.
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I’d certainly be very hesitant to use on track with that LM.
Motul is better at 5.8. But I tend to think Amsoil is the superior oil in this case. Ravenol would be another interesting option. Of course if you use Motul and change frequently, it’s probably not going to make a difference.
Last edited by mkiv808; Nov 21, 2024 at 09:39 AM.
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300V is an excellent oil for track though, but does require fairly frequently oil changes.
Personally I would not use that LM even for road use. Not when there’s so many oils that will shear far less.
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