As info only; I recently emailed Valvoline and asked them about the Group 3,4 and 5 makeup of their synthetic oil. They replied back and said that Valvoline uses a special blend of Group 3, Group 4 PAO, and Group 5 Esters in the blending of their synthetic oils. When I contacted Castrol they would only say that the makeup of their Castrol Syntec synthetic oil is proprietary.
Ask them how much Group 4 and 5 they have. Probably a very small amount, which is why they don't claim it on their website. Or maybe the people who answer questions on their website are idiots, I don't really know.
But the idea that Mobil 1 has no PAO/ester stock as suggested by another poster is simply incorrect. Here is a news story about shortages in Mobil 1 products as a result of Hurrican Ike damaging the ExxonMobil PAO plant:
PAO Shortage Squeezes Mobil 1
By George Gill
10/28/08
The continued shutdown of the ExxonMobil Chemical polyalphaolefin (PAO) plant in Beaumont, Texas, has forced ExxonMobil Lubricants and Specialties to institute a sales allocation on a variety of Mobil 1 synthetic lubricants, effective Oct. 1.
“On Sept. 15, ExxonMobil Lubricants and Specialties was notified by our primary polyalphaolefin supplier, ExxonMobil Chemical, that Hurricane Ike had caused significant disruption to production capabilities at their Beaumont, Texas, plant, and to the ability of their suppliers to make deliveries of critical raw materials and services to the site,” the company told customers in a letter obtained by Lube Report. As a result, ExxonMobil Chemical implemented an allocation on sales of PAO base stocks to customers including ExxonMobil itself. “This allocation is expected to last several months,” the letter stated.
According to Lubes’n’Greases magazine, the Beaumont facility is one of the world’s largest PAO plants, with capacity to make 82,000 metric tons per year.
ExxonMobil spokesman Kevin Allexon confirmed yesterday that the PAO plant remains shut down due to the hurricane damage. “We have folks working on the repairs, we’re making good progress, but there’s no timetable for how much longer it will be,” Allexon told Lube Report.
According to the advisory letter, customer liftings are restricted to 100 percent of prior purchases on products such as Mobil 1 SAE 0W-40, 5W-40 and 15W-50 engine oils; on Delvac Synthetic ATF; Mobil 1 High Mileage 10W-30 and 10W-40; and Extended Performance 5W-20, 10W-30 and 15W-50 motor oils. Also at 100 percent allocation is Mobil 1 ESP 5W-30.
There is a 65 percent allocation on the brand’s SAE 10W-30, and the allocations drop even further for Mobil 1 0W-20, 0W-30 and 5W-20 oils, to 25 percent. Truck and SUV 5W-30 is also at 25 percent allocation. The tightest allocations are those in force for Mobil 1 5W-30 (20 percent) and EP 5W-30 (15 percent).
In the letter, ExxonMobil explains that a product on 100 percent allocation means a customer can continue to purchase it at the customer’s average 2008 purchase levels. Volumes for the allocation are based on a customer's average monthly purchases from January to August 2008.
http://www.imakenews.com/lng/e_article001239508.cfm