I am back with comments about my 01 Chevy Silverado 2500HD, 6.0L with 4 spd auto. It's about 5340 lb on the GM Pontiac factory's scales with (I was told at the dealer) 3 gallons of gas in it.
I've owned it since new, and after 2 short OCI's with VWB, then went to M1 10W30 thinking it would be the best for my application. Then later 5W30. Having a few jobs during that intervening time where I only went on trips 2 - 6 mile trips, and not seeing any or very little oil consumption, I seemed fine on the truck's recommended OCI + 1k, which turned out to be 4,800 to 5,200 + 1,000 = 5,800 - 6200 miles. Since the OM doesn't suggest syn, I thought I would be maintaining the motor in top shelf shape because I also used the stock AC filter.
Then sometime with around 45k miles I got an OCI that abruptly ended at about 5500 with the digital information center saying "Low Oil." It turned out to be 2 1/2 quarts low, some time in spring of '06. In one OCI my motor had gotten the oil consumption disease, and it looked like it was there to stay.
I've continued to run M1, and after adding a quart at 2k mi intervals I eventually got down to a quart every 1.2k - 1.4k, and changed oil right when the OLM recommended to. That was 2 1/2 years ago.
Then, so many on the PCMO board, made it sound like it would make more sense to use the one of the "High Mileage" versions of a major name brand to clean up the rings and reduce that consumption. Since then the mileage between adding a quart got up to 1800 miles. I was thinking there was some permanent wear in the cylinders or something. I seafoamed thru the PCV, then replaced the PCV, and even ran MMO in the gas, and got improved operating, especially at idle and significant throttle pull/ acceleration. I attribute it to the lubrication qualities in the pump and port FI system, maybe some intake valve cleaning. But I still didn't get the oil burn to a mileage I would have felt ok about, which I thought would have been over 2500 miles.
So 3 months ago, at 102,130 miles, when I was 1 quart down, I added a quart of MMO to the oil about 3500 miles into the OCI then ran for 830 miles with temps from 50's to 80's (F). I'm now 1800 miles into the next OCI also having switched to Motul 8100 5W30, and - I am shocked for almost 2 months into the OCI now, and am being convinced every day when I repeatedly pull the dipstick - the dipstick is now reading. . . less than 1/8 of a quart low!!! Never imagined that consumption could get this low. If it was a full 1/8th of a quart low that would translate to 1 quart every 14,400 miles!!!
Because I've made two changes in my oil regimen, there will be inevitably be those that cynically apply their scientific method and say my example proves nothing, or in reality, what they want it to prove.
Some will believe "snake oils" can't deliver as advertised.
Some will claim with certainty the using oil which is the "old school" or German definition of synthetic has no real benefit to your engine unless you're running tuned/ turbo/ high performance/ special fuels/ racing.
Some will sing the praises of Mobil 1, "full" synthetic with a group III comprised majority. How could there be anything wrong with "the" NASCAR synthetic you buy off the shelf?
Some will say the M1 HM oil was just waiting for its chance, and boom, after a 600 miles per quart improvement in round 15, and adding almost that many quarts between OCI's since starting the 4 OCI's on the HM diet, M1HM suddenly delivered the knockdown blow to my varnished rings, and bingo! Then like total opportunists, marginal and suspect products have stepped in to claim all the credit.
Some will demand an accounting of money spent through an oil change interval. In that time I would use 6 qts for the change and another 3 during the OCI. 9 quarts at $26 per 5 qt jug (incl sales tax) = $46.80 US. The Motul ran $50 / 5 liter jug (with shipping), and we all know 6 quarts = 5.68 liters + 0 quarts make up oil, which comes to $56.78 US, if I use the same OCI. I calculate would be breaking even on the oil expense if I could go to 6200 miles with no makeup oil, or about 1000 miles more than that with 1 quart of makeup oil.
Now I'll have to see if the Motul can hold up for the full OCI, go for and extended OCI, and hold up to a UOA. I'm sure a lot of credit goes to the MMO for dissolving the crud responsible for the blow-by and consumption, but I will entertain the inevitably harsh conclusions that must be drawn by the "anti-" critics.
I've owned it since new, and after 2 short OCI's with VWB, then went to M1 10W30 thinking it would be the best for my application. Then later 5W30. Having a few jobs during that intervening time where I only went on trips 2 - 6 mile trips, and not seeing any or very little oil consumption, I seemed fine on the truck's recommended OCI + 1k, which turned out to be 4,800 to 5,200 + 1,000 = 5,800 - 6200 miles. Since the OM doesn't suggest syn, I thought I would be maintaining the motor in top shelf shape because I also used the stock AC filter.
Then sometime with around 45k miles I got an OCI that abruptly ended at about 5500 with the digital information center saying "Low Oil." It turned out to be 2 1/2 quarts low, some time in spring of '06. In one OCI my motor had gotten the oil consumption disease, and it looked like it was there to stay.
I've continued to run M1, and after adding a quart at 2k mi intervals I eventually got down to a quart every 1.2k - 1.4k, and changed oil right when the OLM recommended to. That was 2 1/2 years ago.
Then, so many on the PCMO board, made it sound like it would make more sense to use the one of the "High Mileage" versions of a major name brand to clean up the rings and reduce that consumption. Since then the mileage between adding a quart got up to 1800 miles. I was thinking there was some permanent wear in the cylinders or something. I seafoamed thru the PCV, then replaced the PCV, and even ran MMO in the gas, and got improved operating, especially at idle and significant throttle pull/ acceleration. I attribute it to the lubrication qualities in the pump and port FI system, maybe some intake valve cleaning. But I still didn't get the oil burn to a mileage I would have felt ok about, which I thought would have been over 2500 miles.
So 3 months ago, at 102,130 miles, when I was 1 quart down, I added a quart of MMO to the oil about 3500 miles into the OCI then ran for 830 miles with temps from 50's to 80's (F). I'm now 1800 miles into the next OCI also having switched to Motul 8100 5W30, and - I am shocked for almost 2 months into the OCI now, and am being convinced every day when I repeatedly pull the dipstick - the dipstick is now reading. . . less than 1/8 of a quart low!!! Never imagined that consumption could get this low. If it was a full 1/8th of a quart low that would translate to 1 quart every 14,400 miles!!!
Because I've made two changes in my oil regimen, there will be inevitably be those that cynically apply their scientific method and say my example proves nothing, or in reality, what they want it to prove.
Some will believe "snake oils" can't deliver as advertised.
Some will claim with certainty the using oil which is the "old school" or German definition of synthetic has no real benefit to your engine unless you're running tuned/ turbo/ high performance/ special fuels/ racing.
Some will sing the praises of Mobil 1, "full" synthetic with a group III comprised majority. How could there be anything wrong with "the" NASCAR synthetic you buy off the shelf?
Some will say the M1 HM oil was just waiting for its chance, and boom, after a 600 miles per quart improvement in round 15, and adding almost that many quarts between OCI's since starting the 4 OCI's on the HM diet, M1HM suddenly delivered the knockdown blow to my varnished rings, and bingo! Then like total opportunists, marginal and suspect products have stepped in to claim all the credit.
Some will demand an accounting of money spent through an oil change interval. In that time I would use 6 qts for the change and another 3 during the OCI. 9 quarts at $26 per 5 qt jug (incl sales tax) = $46.80 US. The Motul ran $50 / 5 liter jug (with shipping), and we all know 6 quarts = 5.68 liters + 0 quarts make up oil, which comes to $56.78 US, if I use the same OCI. I calculate would be breaking even on the oil expense if I could go to 6200 miles with no makeup oil, or about 1000 miles more than that with 1 quart of makeup oil.
Now I'll have to see if the Motul can hold up for the full OCI, go for and extended OCI, and hold up to a UOA. I'm sure a lot of credit goes to the MMO for dissolving the crud responsible for the blow-by and consumption, but I will entertain the inevitably harsh conclusions that must be drawn by the "anti-" critics.