Rotella T4 15W40 Vs Mobil Delvac 1300 Super

Aug 22, 2019
This is very outdated and Im sure doesn't apply to current oils. 20 Years ago I ran Chevron Delo 400, Mobil Delvac 1300 and Shell Rotella T 15W-40 in a 1999 Cat 3406E in a dedicated route. With 30,000 mi drains (Max allowed with UOA) and 2 gallons of add oil (Roughly 20% of capacity) the TBN was at 50% of new and viscosity was slightly below new (No thickening). Soot was very low. All three oils performed essentially identical. It consumed slightly less Delo and at the time it was slightly cheaper so that's what I ended up running for 30,000 mi OCI. Truck was sold with just shy of a million miles. Oil consumption had increased 50% over roughly 900,000 mi.

I don't follow - what is outdated?
Synblend? ----->


Aug 6, 2018
The sample was sent blind (by Shell) to an independent third party lab. Note it is not the same as, Shell sent an independent lab $40 to buy their own jug of Mobil and jug of Shell. Shell provided both samples of oil. Shell had ample opportunity to mix up a special batch of Rotella that would win a gold medal, and also to send in a defective or adulterated sample of Delvac they knew would not pass. See, Shell is the one that selected both samples of oil. To claim that Delvac does not meet the API standard would get them sued by Mobil, so all they can say is “the sample that was tested” failed.

An independent third party can be fooled, or can be complicit in a scam. To permit one vendor to supply the competitor’s oil does not pass the smell test.