This is the best oil on the market to use on old, worn gas engines. Yes gas engines. Diesel oil has far more detergent in it than other high shelf gas oils and cleans engine internals and piston rings very well. By using this alone without doing anything else, it literally cut the oil consumption on my old audi 1.8t by more than half. The engine has over 250K miles on it and was consuming about 1 qt every 750 miles. Now it only uses about 1.5 gts every 2000 miles and I change it at 3000. For the last half qt top off I use marvel mystery oil for about the last 1000 miles of an OCI. My car no longer smokes and no longer has a burning oil smell. I am extremely pleased with this product.

This oil came highly recommended to me by an Atv mechanic for use in my Honda 500 Foremans and Honda 420 Ranchers. I did plenty of research and found that many Atv enthusiasts prefer the full synthetic T6 oils such as Rotella. This oil meets all JASO MA requirements for Motorcycle and Atv wet clutches . JASO MA is the standard for single unit engines where the wet clutch, gearbox and engine used the same oil. JASO-MA oils dont contain friction modifiers that will cause a wet clutch to slip Seems like excellent oil so far. I have also noticed that the engine cooling fan does not come on nearly as much as when I was running standard oils. I will be staying with Rotella 5w-40 T6 for all of my Atvs from here on.

I had previously done an oil change with an ACDelco filter and Mobil-1 5W-30 and noticed my oil pressure slowly getting lower and lower over a period of a few weeks. Oil pressure went from around 28psi at idle to less than 19psi and wouldn’t go over 35psi when driving, I diagnosed it as a defective or collapsed filter and switched to a Wix XP filter and this Shell Rotella T6 5W-40 for some extra viscosity and protection at operating temp, since then my oil pressure has been great, 33psi at idle and oil pressure goes well over 45psi when accelerating. So if you’ve got a gen 3 or 4 Vortec with low oil pressure consider making the switch to Shell Rotella and either a Napa gold or Wix XP filter.

Do you have a modern diesel engine? Consider this Group III oil for your lubrication needs. This is a full 'synthetic' oil that is Diesel Particle Filter friendly to control emissions. The 5w-40 oil is good for a cold start and provides protection when at running temperature.

Did some research and found out that this oil contains the additives of older style oils of the 60 and 70's! So it protects the older engines with the type of parts that the newer oils don't necessarily cover. Put it in my old Jeep Cherokee and notice a much quieter running machine with a more consistent oil pressure. We will see how things work out after another 1000 miles or so on this batch. And I'm changing over all the oils in my 4 other vehicle to this also!

Been around diesel equipment for forty years and have tried other oils but have always gone back to shell Rotella. Check truckers websites, read articles about diesel oils. I would not but anything in my diesel engine except Rotella now for the best grade T6 is what you want .

This oil does exactely what its supposed to do! Engine is quieter, runs smoother, and stays cooler. Unfortunately for me, my car calls for 5w30 and this is 5w40, thus my avg. mileage, after three tank refill periods, did go down by 1 mpg. (1995 Buick Roadmaster 350/Lt1 w/34000, yes only 34,000 miles). Combo city/hwy 15 mpg to 14 mpg. Oh yea, Walmart will probably be the best price around, however they sell it higher in the stores than online (and they will not honor/price match any online prices or ads, even if you choose the ads for that particular store). So, do their online ship to store option, you will have to pay online but at least you get the discounted price. Plus go to the Shell Rotella site and sometimes they offer a $5 mail in rebate offer to, makes it 14.22 a gallon, not bad!

Get the 5 W-40 vs. the 15W-40. Especially if you're living anywhere the temp goes below 40 degrees often. Check the forums and do the research. No comparison in performance! If you live in a hot climate, the 15W weight is fine. Happy motoring!!

Shell Rotella T6 synthetic oil is truly worth the money. It's performance is excellent in our heavy duty Peterbilt 387 CAT C15 engines and our 2002 Ford F350 Super duty 7.3L V8 turbo deisel engine. We will not put in any other oil in our CAT C15s, they run smooth with no knocks. We usually buy this by the barrel, but needed it sooner.

I like this oil because I don't have any oil consumption issues. It is the recommended oil for my diesel pickup (10.5 quarts). I change it and filter myself at approximately every 8,500 to 8,800 miles (10K recommended by Ram). About .5 quart is missing when it is changed with the filter. This has been consistent since it was new. No leaks are apparent. Currently have 80K miles on the engine.