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Mobil 1™ 0W-40

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    Mobil 1™ 0W-40

    Walmart has this at a lowered price now, so I thought I'd give it a try with a GM 2.8 V6 engine that has a slight oil consumption, as in 1/2 quart per 3,000 miles.

    Needless to say overall, a Full Synthetic Motor Oil of any brand will be a better quality than traditional oils. But, I will say that frequent oil/filter changes with traditional oils can make an engine last a long time.

    I wanted to see if overall oil pressure would be a bit higher, than compared to 5w30 or 10w30, and it passed this test.

    Its Viscosity Index is 185, whereas Mobil's 10w30 is 149, so one would expect overall oil pressure to be a pinch higher.

    I use other oils like PENNZOIL ULTRA PLATINUM® 10W-30, so I'm not brand specific; but I have found that some of those cheaper oils can increase oil consumption on older engines.

    They say that it "Provides exceptional cleaning power for dirty engines," but other oils (API SN, ILSAC GF-5, or dexos™ branded oils) have good detergent packages also, some better than others, as they say.

    If I was doing some long distance summer driving in hot weather conditions with an older engine, I might consider Shell Rotella T5 15W-40, or even Rotella 15W-40.

    I like to buy the lower priced synthetic oils, when available; but most all oils today work just fine, but some will increase oil consumption....YMMV with your conditions.

    Fuel mileage wise, the same or a pinch better (<1 mpg).

    I've used Mobil 1™ 0W-30 during winter months, and it does quite well. I will try Mobil 1™ 0W-40 this winter and see how it performs.

    After 1,000 miles, oil level is same as installed.


      I have run most oils over the years in my 3800's, But for me my 3800's seem to burn oil or burn next to nothing.. I have 2 that use oil, say 3/4-1 quart in 3K miles.. I have used regular 5w-30, 10w-30 and 10w-40.. Dino, Semi Synthetic, High Mileage Semi Synthetic, as well as Synthetic.. Mine seem to use the same amount no matter what I used... However with the synthetics I seem to maintain better oil pressure over the life of the oil.

      I do buy what I can get the better deals on tho.. Currently I have a boat load of


        Originally posted by Jr's3800 View Post
        seem to burn oil or burn next to nothing
        When oil control rings get "sludged," there goes the oil out the exhaust pipe. I highly suggest using Pennzoil High Mileage Vehicle Motor Oil for two oil changes.

        I was about to rebuild a B230F Volvo engine, which was "pissing" oil (1 qt per 400 miles), but Pennz oil cleaned up those rings. An university student had vehicle for some six years, and it was driven few miles, and most likely, few oil changes. Its a good engine now.


          As noted, it seems the fuel mileage is a pinch better, but this is hard to nail down.

          In their literature, they indicate, Mobil 1 0W-40 is designed to offer improved fuel economy, but they are comparing 10w-40 and 5w-40 oils to Mobil 1. However, I suspect fuel economy is more similar to a 10w30 oil.

          This oil has a Lower Volatility, which means this Reduces oil burn off...and after 2,000 miles, the oil level is holding steady. With a cheap oil, oil volatility may be an issue with older engines; with the generic 5w30 oils, the oil consumption will go up.

          So far, no complaints, except the price.


            You can almost always find M1 full synthetic on sale somewhere with a decent free filter. I've used 0w-40 in the Saab for years, and started using their 5w-30 in our Fiat. I like being able to go 10k without having to crawl under the car, plus squeezing every last mile out of synthetics washes out the added cost.
            - Joe


              At 3,500 miles, less than a 1/2 quart had been added, so I changed out oil/filter with Mobil 1™ 0W-40 again. It seemed to consume a pinch less oil than 5w-30 and 10w-30 weights.

              Instrument cluster had been changed out on this vehicle, so I have no idea what its true engine miles are; when I got it, I had to replace rods/mains and installed a new oil pump...very low hot-oil pressure.

              They say this oil has "frictional properties that aids fuel economy," and based upon consistent fuel mileage around 30 mpg during this summer's heat, I really doubt a 5w-30 oil would show little fuel improvement.