I have a 17 year old Volvo TAMD41P-A diesel in my 31' recreational trawler. Prior engine oils for the prior owner (11 years) and me have been 15-40 dino oils, until I switched to full synthetic engine oil, also 15-40. Operating temperature dropped 5 degrees at standard cruising RPM of 1800 to 2200 (only one of two thermostats in place most of that time), the engine runs quieter and more smoothly. Based on research I have found, I know that my engine is running cleaner, with other attributes of reduced internal corrosion, less wear, etc. After installing 2 new thermostats, the engine runs precisely on specification for operating temperature through the full range of RPM, right up to wide open throttle, 3800 (end of the day 10 minute spike to clean the exhaust system ). Further, smoke when starting is greatly diminished to almost zero. I am completely satisfied that I am doing all that I can to accomplish optimal engine performance and protection with Rotella T6 over the last two years, and I am comfortable recommending Rotella T6 to boating friends with diesels, confident in the cost/benefit of using the best oil quality, grade and viscosity for my application.

I have a Kawasaki 1500, model year 2000. I switched to this oil because someone with a similar motorcycle tried it and liked it. Major reason for me switching to this is because it was a full synthetic and very reasonably priced compared to other full synthetic motorcycle oils. I've put on 2000 miles since my oil change and I have started to notice severe clutch slippage. At first it was barely noticeable but as of right now, I have a hard time getting on the interstate without it slipping. Now, whether it is due to the recent oil change or some other Factor, I'm not sure if I would recommend this oil for anyone to use in a wet clutch motorcycle or not.

Used T6 in my 2007 FZ1 since I bought it used about four years ago. I rev this bike to the Max, never had a single engine problem, doesn't run hot, uses zero oil in between changes. I understand that it shears easily in a wet clutch situation (as do many oils) so I change it as I reach about 1k or 1.2k miles that way the engine always gets fresh oil. It's cheap and not that hard to change oil and filter. I only ride for fun so I change it maybe a couple of times a year.

As a 6.7 cummins owner that hauls a 12,000lb 5th wheel I trust my Ram to get me where I want to go and not worry about my motor. I have used nothing but Rotella T6 and will let my consumption guage get to 15% life left before I change the oil and filter. After driving 7,000 miles and changing it I could still feel the heaviness to the oil so I know this oil isn't breaking down prematurely. I won't trust my engine to anything but this oil

I use T6 5W-40 for all non catalyst engines from small engines to tractors and older gas trucks. I live in ND where the temps range from -30F to 100F in a season and this oil has performed excellent in both gas and diesels. The only thing that sucks is the ZDDP will smoke o2 sensors in newer vehicles so I quit using it there. Nice to have one oil do the job of three.

I have been using ROTELLA Full Synthetic for 10 years in my Honda ST1300. I Change it every fall when putting the bike away for the winter. I have 180000 km on the bike. It does not burn a drop of oil. This bike is not a stranger to the far side of the speedometer.

I've been putting the T-6, 5/40 in my '09 Yamaha 1900cc air cooled Raider for about 6 years now as a winter weight oil. It starts a lot better than with the 20/50 and it's been running great for years with absolutely no oil burning. Bike has 50,000 miles on it now. Great friggin' product. Love it.

If you idle your diesel engine much this is your oil. It won't break down like a non synthetic oil and thin out. My 6.7L Cummins engine starts much easier in cold weather. It rolls over twice as easy. It snaps right off and does not drag even at zero degrees outside. It is going to help my batteries last much longer and reduce engine wear at start up. I do a oil and filter change every 5000 miles. My engine has 215,000 miles on it.

My '99 Honda Valkyrie motorcycle, '02 BMW 1150GS motorbike, '91 Lexus LS400 and '04 Dodge 3500 diesel, all use Rotella synthetic. It is so nice to keep one oil for everything and still find that excellent cold weather starting and hot summer oil pressures are still great. I recommend this product without reservation.

i have buying t6 full synth 15-40 for my two powerstroke 05 ford 6.0 diesel and 08 ford 6.4 diesel in my 6.0 engine i change every 2000 and at the most 3000 miles and because after 1000 the shearing is very noticable at 500 miles its completely black i now the 6liter are hard on oil but i have spent well in the thousands in oil changes just year rotella t6 nothing else