Featured Motor-oil shortage on the horizon

Just to reiterate, GTL base oils are second only to those made from Group IV (PAO) and Group V (POE, AN, etc.) base stocks in base-oil quality. The Shell Pearl GTL facility was one of a kind in terms of capacity, and it’s a pity it will be decommissioned for a while.

In the curve below, for a given CCS (cold-cranking start) viscosity, the lower the Noack volatility, the higher the base-oil quality, resulting in a higher viscosity index, a lower oxidation rate, and so on. As you see, natural-gas-based GTL is roughly equal to Group IV (PAO) in base-oil quality, and it far surpasses petroleum-based Group III base oils. As you can also see in the figure, it is even hard to meet the GM dexos1 Gen 2 spec—the horizontal line that indicates a 13% maximum Noack volatility, which has actually been even further reduced to 12.5% in GM dexos1 Gen 3—without using some percentage of GTL base stock in the base-oil blend. So, the problem is not limited to European specs, such as the Mercedes–Benz (MB) specs, which specify a maximum Noack volatility as low as 11%.

 

Naysayers in this thread were quick to jump in after a quick AI search to say GTL is used in very few oils. Hint: AI is very bad at answering questions that require knowledge not commonly available on the Internet.

The fact is that all low-viscosity oils, such as 0W-8 or 0W-16, must include some GTL or PAO in the blend, not necessarily 100%, perhaps as little as 10–25%, but enough to reduce the oil’s volatility. Since PAO (Group IV) is expensive, most use GTL. The reason is explained in the following figure. When viscosity is lowered, you need a higher base-oil quality to meet the maximum Noack volatility requirement. In fact, 0W-8 and 0W-16 are not even shown in the figure; they would be all the way to the left. So, you need some percentage of your base oil to be GTL or PAO to lower the Noack volatility to the maximum spec. The problem is that you can’t substitute PAO for GTL or vice versa if there is a shortage, because that would require new engine testing, which is very expensive and time-consuming, to recertify the blend.

 

Details on the Toyota Genuine Motor Oil (TGMO) shortage, arising from the shortage of Shell Qatar Pearl GTL base stocks, after the facility was bombed by Iran, which are blended into the base oil to lower the Noack volatility of the base oil in thinner oils. They will be using TGMO 0W-16 for TGMO 0W-8 and TGMO 0W-20 for TGMO 0W-16. There goes my fuel economy!

Toyota is about to run out of motor oil | Autoblog