The V8's Thirst for Unicorn Blood

I like to find ways to make Aston ownership more feasible for those of us that appreciate a nice cost savings. The main driver for ownership costs is basic maintenance. As I cover in my blog post about the thermostat, you can cut a $450 thermostat replacement bill down to $60 and two hours or less of your own time. One area you can save quite a bit is by doing your own oil changes.  The oil change isn’t really that hard – there’s only a couple extra steps to do the oil in a V8 Vantage compared to any other “normal” car. The downside is that it’s still going to be expensive due to the type of oil and the amount required.

Even though oil changes are pretty much the most basic jobs required for a car's maintenance, it's worth a blog post to discuss the oil used by Aston Martin. There are plenty of questions regarding what to use, where to get it, why it costs so much... Hopefully this blog post will help explain things a bit and clear up any confusion.

The Price of Unicorn Blood

Let's just clear the air on this really quickly. 10W60 oil is expensive. I'm no chemist but I'll try to share a bit of what I've read about the topic. Motor oil contains additives that allows it to do its job over a wide range of temperatures. That range is expressed by the SAE weight rating (in our particular case, "10W60", with 10-to-60 being the range). Additives are used to get the oil to work over a range of temperatures. These additives are polymers that change during heating so the oil can keep working at the engine heats and cools. It's far more difficult to engineer an oil that can work effectively across a wide range of temperatures (ie, 10W60) than it is to engineer an oil with a narrower operating range (ie, 5W30).

In addition to the difficulty of creating the oil, a second factor is that an oil as heavy as 10W60 is typically going to be used in high-performance cars that are going to be driven as such. Given the demands of engines used in this capacity, the oil will typically need extra additives to help it cope with demanding use. The extra additives add extra cost.

Aston's Recommended Oil

The owners manual for the V8 Vantage specifies Castrol Edge Sport 10W60. There has been a lot of concern about this, because people are confused by Castrol’s marketing. Here’s why:

TWS is not a brand/sub-brand/etc. TWS simply stands for “ten-w-sixty” (10W60).

Edge, Edge Sport, and Edge Professional are the same thing but with slightly different additives. And, over time, those additives have changed.

Castrol TWS could be purchased from a BMW dealership at a much more reasonable price than from an Aston dealership (say, $13 vs $18 per bottle). Those savings add up quickly when you need 10+ bottles for a single oil change! The reason this is confusing is because BMW switched oil suppliers and now uses Shell-supplied “TwinPower” oil instead of Castrol. If we're supposed to use BMW M-specified oil, what does that mean with Shell's new oil added to the equation?

All this taken together leaves the DIY owner trying to figure out with they should use Castrol Edge, Castrol Edge Sport, Castrol Edge Professional, Castrol TWS, or Shell TwinPower. Here’s the easy answer:

If you’re that worried, stick to the stuff specified by the owner’s manual: Castrol Edge Sport 10W60.

Oil Ratings

If you’re open to trying other types of oil, whether its for the benefits of better performance or cost savings, then you can use any 10W60 oil that meets the minimum requirements:

API: SL/CF
ACEA: A3/B3/B4

Many of you are probably wondering what those letters and numbers mean. Basically, they’re quality standards for oils. The new the standards, the higher the quality required to meet those standards. Rather than re-hash the explanations, here are the specs for API and the specs for ACEA.

The one that is slightly more confusing is the SL requirement. All you really need to know is that the second letter is replaced alphabetically as the oil standards change. SL was the top standard when the V8 Vantage was first made. Then SL was superceded by SM. Now there’s SN. So if you’re looking for oil, just make sure it’s got an SN rating and you’re good – it’s better than the original requirement. In some cases, the oil itself may be identical to what it used to be when it was SL-rated and the rating has now been increased to SN. Don’t get hung up on that. It just means the oil is still meeting rating requirements even as those requirements get more stringent.

You can ignore the API CF requirement – the C-ratings are for diesel engines. If you’re curious, the rating schema is the same for those as the S-ratings. CF was superceded a few times and the current diesel-based rating is CJ-4.

Factory Oil – Aston Martin and BMW

Let’s take a few minutes to go over the factory specified Castrol oil. Castrol originally supplied both BMW and Aston Martin with TWS oil. BMW used the oil in their V8 and V10 M-cars (M3, M5, and M6). In early 2015, BMW dropped Castrol and started using Shell-supplied “TwinPower Turbo” oil for those cars.

Photo from ECS Tuning

Photo from ECS Tuning

Funny side note: The TwinPower Turbo oil for the V8/V10 M-cars is NOT to be used in the turbocharged “TwinPower Turbo” M-cars! The current generation of M-cars use twin-turbo inline-6 (M3/M4) and V8 (M5/M6) engines called "TwinPower Turbo" engines. Some genius in Shell’s marketing department named the oil after an engine it can’t be used in. So just a heads-up in case you’re wondering – the name is meaningless and actually misleading.

Anyway, back on topic… I’m willing to bet the change in suppliers is entirely contractual – BMW’s contract with Castrol was likely up and Shell offered a sweeter deal. As for the oils themselves, they’ve very similar on paper. A key difference in the specs I found online is that the Shell oil has a much higher 250°C (482°F) flash point than Castrol’s 203°C (397.4°F) flash point.

As for the original Castrol Edge oil… it’s been reformulated, rebranded, and relabeled more than a couple times since its original release as Castrol TWS. If you want to use it, both of the current Edge Sport and Edge Professional oils are rated SN (exceeding Aston’s original SL requirement), and both are listed by Castrol as being suitable for the V8 Vantage. Regardless of which Castrol Edge you end up using, you'll be fine so long as it's 10W60.

Photo from ECS Tuning

Photo from ECS Tuning

Just to add a little complication to the mix: You can use 5W50 oil if 10W60 isn't available. It's a thinner oil so keep in mind that it's better for colder climates and might not be a great idea if you're driving the car hard in warmer areas.

Other Oil Options

10W60 oil isn’t as common as, say, 5W30, but we still have options. In addition to Castrol and Shell, Redline, Royal Purple, Pennzoil, Mobil1, Motul, and others make 10W60 engine oil. When you look at them, just make sure they’re rated at least API SL/CF and ACEA A3/B3/B4.

Motul has a newer formula called X-Power 8100 that I’ll be trying out starting in about a month. I’ll be sending a sample of my used Shell TwinPower oil to Blackstone Labs to get it analyzed, and doing the same once I’ve put some hard miles on the Motul, then posting the results comparing the two in the future once they’re ready.

If you aren’t familiar with Blackstone Labs, do a quick Google search and you’ll see them pop up. You’ll probably see a lot of links to bobistheoilguy.com, which has more information about oil than most of us could ever consume. The reason Blackstone’s tests are so useful is because it’s incredibly hard to compare specifications supplied by oil manufacturers. Blackstone analyzes oil samples to determine the actual qualities of an oil and how that oil has survived over time. So stay tuned for some real-world testing of various oils in the months to come!