20 Best Synthetic Engine Oil For Diesel Engines (2023 Updated)

IšverstiShow in original languageThis motor oil is the best! It contains gold, platinum, palladium, and lots of other things which multiply in your engine, increasing the value of your engine, and making your engine impossible to ever wear out! Furthermore, it increases the power in your engine to such an extent that it can propel you to and beyond the speed of sound!.

wait a minute. What the heck am I talking about. It’s good oil.

IšverstiShow in original languageI used the Rotella products for decades in my trucking companies. ( & my personal diesel pickups. ) In Millions of miles for semi-trucks, using oil testing labs to continually monitor oils, I was able to extend oil drain intervals significantly.

In all those years I NEVER had ONE oil related failure or indication!! One such truck I took out of commercial service & continued to use it for personal use for 7 more years. I sold it with 972k miles, & Still had never needed to do an engine overhaul!! ( that was with NON synthetic oil ) Now that synthetics are available, my personal trucks use this exclusively!! I grew up in Northern NY, on the Canadian border, & value the cold weather performance of synthetics even more.

IšverstiShow in original languageThe oil is great! But somewhat expensive. It would be much more convenient if this oil was available in 5 quart or better yet 6 quart containers. The traditional gallon size is too small for my Jeep Wrangler.

This means I wind up buying two gallons every time I change oil. The remainder winds up in my lawn mower and snowblower.

I have a 2014 VW Passat TDI and sent the oil in for analysis to see how it was wearing. I couldn’t believe all the low wear numbers. Way below the averages for my engine and mileage. My car’s DPF, EGR, and SCR system fell off which is why I’m not using the VW 507 approved oil by the way.

If you have a TDI with the emissions still intact, I would recommend using this oil instead of the “approved” VW 507 oils. The oil thickness once warm (100* celcuis spec) is not much higher than the 507 approved oils.

Think of it as the TDT is a “thinner” 40 weight, and the VW 507 oils a “thicker” 30 weight oil. The ash # is still low enough to use in anything with a DPF. I have switched over to the Mobil TDT in all 6 of my Diesels I own.

The anti-wear additive is very robust.

I went into the O’Reilly Auto Parts in Edgewood, New Mexico, with the sales ad marked so I could purchase the jug of Mobil 1 Turbo Diesel Truck oil and then send in for the $10 mail-in rebate. I looked on the shelves, but could not find the oil.

I took the ad to the counter and showed it to the lady there. She went back and brought out two jugs of oil. She could not find the rebate forms. After draining the oil from my car, I remembered about the form, so I looked at O’Reilly’s rebate page.

The rebate, I found there, was for FIVE quart jugs of oil, not the FOUR quart jugs I purchased. Since I’m 15 miles from the store and the drained car is my only transportation, I had to use 7 quarts to fill my crankcase.

Since the special has run out, I cannot now buy two additional quarts of oil to use the rebate form. I’m not happy.

Brought a used 2002 Ford Taurus 3. 0 SOHC SES in June 2015. Vehicle had 96K miles at the time. Started using M1 HM about six months later. I replaced oil pan gasket, timing cover gasket, and recently both valve cover gaskets, and radiator during this time.

So, I started using M1 High Mileage and put conventional oil in my rear-view window and ain’t looked back!! Now the vehicle has 155k miles and engine runs so quite I barely hear it running! Engine runs cool, starts right up, good acceleration, and low oil consumption with no leaks! I check my oil about 5k and check it again at 7k.

At 75k, oil is changed; and I noticed that the oil is still thick (compared to conventional oil which I noticed is thin and “black”) and has a light brown huge. No sludge forming in oil filter which is a M1 performance filter.

I had a previous Ford Taurus and had two head gasket replacements and car would occasionally run hot. Eventually, I got rid of the car and learned that conventional oils loose their velocity with can cause an engine to overheat and develop heavy sludge in the engine etc.

Bottom line: Once you go synthetic oil, you never go back. Synthetic costs more but cheaper than having a head job done or replacing an engine.

After hearing and reading rave reviews on this oil, and reading posts about it on oil-focused sites and forums, I thought I would give it a try. Im running it in my 04 Grand Caravan with the 3. 3L V6.

Running a half-and-half mix of 5w-40 and 15w-40. Let me say this, my van has never ran so well just by changing the brand and type of oil I am using. It currently has 209k on it and runs like a top. I switched to diesel oil because it has a higher film strength, better wear packs, and better detergent packs than gas oil does.

I want my van to run as long as possible. I am one of those people that drives a vehicle until the wheels fall off, so they say. Ive used other brands before and they have worked well, however, since changing to Rotella T6, my van has more power and response than I ever remember it having.

Rotella and other Shell products will be my only brand now. Stocked up on quite a bit of Rotella in all its major types, T4, T5, T6.

I own a towing company. We are classified as emergency and NEED every truck to start, run well, and last a long duration. Over the years weve tried everything. Currently, we run older 7. 3 diesels and new 6.

7 diesels. There is hands down a HUGE difference in cold starting and gas mileage, and performance. So much easier for the pumps, and a smother running engine. Its no joke, this oil has been used since it came out in out trucks, and our 7.

3’s have zero internal issues with between 500k and 800k miles on some of the engines. Our 21′ and 22′ model year trucks come from the dealership new, oil drained, and t6 put in to make sure the engines get the best protection right from the start.

Yeller Towing, Elk River.

I was running T6 in my Kubota 7040 when I had a wreck while transporting it back from the hayfield. It flipped on its top after I flipped the whole rig over an embankment onto it ms top. The tractor has lugs on the starter that got crossed over by the baler control box and it started while upside down which caused it to “runaway” running entirely on its own engine oil that was being sucked around the pistons becayse it was upside down.

It revved completely off the charts and continued to stay revved like this for nearly 3 minutes until I could get the hood up and get rags shoved down the intake to choke it out. I finally got everything flipped back onto its wheels and poured almost 2 gallons of oil back into the engine to replace what had blown out the exhaust when I wrecked.

Put a hot battery in and it started and has been ran nearly 200 hours since. I feel that the rotella T6 is the one and only thing that saved this engine. The block was so hot when it was running away that it was glowing white on the manifold.

I believe that had I been using conventional oil that It would’ve cooked that engine. Maybe I’m wrong but it’s definitely had to help.

Valvoline Blue is the recommended oil by Cummins, and I want the very best for my baby. In the winter, I use a lower viscosity oil like 10w30 for easier starts in cold weather. The sooner the oil can get around the rings upon starting, the less wear on the engine.

An ounce of prevention is worth a pound of cure. Treat your vehicles well and they will treat you well in return.

I had been running Mobil Delvac 1300 in my 2003 Dodge Cummins. I came to my attention that Ford had issued a statement that CK-4 (latest API spec) was not approved for any Ford diesel, new or old, unless the container stated that it met the Ford Spec.

That raised a red flag with me and I checked the Delvac label and there was no Ford spec or Cummins spec on it. Valvoline Blue carries the Cummins spec approval marking.

Castrol Edge is some of the best oil in the market and far the superior oil you can commonly find in store. Used this in a 2006 CRV with the economy based VTEC k24 variant. Honda engines with VTEC solenoids function far better with high quality oils.

I just wish I could get 0w30 as I live in the 46th parallel and cold weather is a good 7 months here. Pleased with the product no doubt.

Let’s see. I have changed the oil in my Father’s cars since the 60s. And now mine. We used to use the Pennzoil 30 weight back in the day, but since Castro Syntec came around, I use nothing else. I only have two examples since I drive my vehicles till the wheels fall off.

1. Brand new 1989 Geo Metro with a 3 cylinder Susuki motorcycle engine. I think I would still be driving that car now, if in the 2000s, two hurricanes didn’t attack and kill my car while it was parked in Fort Pierce when I was riding a ship for the Air Force in the western Pacific.

It had over 270K when they towed it away. My Father gave me his 1995 Lincoln Towncar since he wanted to upgrade my Mother’s car before he died. It now has over 355K and runs great still! Take care of you car and you will get your money’s worth.

As they say: “Mike Drop”.

I like the idea of the titanium in there but mostly I just trust Castrol oil I put it in my eclipse 3. 8 and and my friends q50 and I’m no longer using the mobile 1 on anything it seems like the budget brand at this point.

I’m back in the castrol camp and changing my own oil out cause more and more the local lube shops are wrecking people’s engines by putting on wrong filters and probably not even the right oil… the sad state of American decline is evident everywhere in Boston ma.

I’ve been running Valvoline 5w40 Premium Blue Synthetic Diesel Oil since 2014. It’s Cummins approved so I figured why not. I use it in all three of our 6. 7 Cummins, never an issue. It is recommended for temperatures across the spectrum, no need to switch back & forth oil weight from summer to winter oil.

I have a 05’ Chevy D max since new. Dino oil that came with it for the 10,000 break in and changed it with T6 ever since. C’mon, you cannot see what is happening inside you engine unless you break it down.

The premise of using a good quality synthetic motor oil is based on the comfort that you WON’T have to break it down because you know that oil is making sure your engine is getting lubed. Diesel engines are quite expensive so putting the best oil in equates to as little wear as possible.

I use a bypass oil filter (installed at 10,000 mile oil change) which gives my T6 the absolute best filtration. Engine has run great and, at 93k still sounds as new. Don’t even think twice about using T6 in your diesel.

Everybody has their pet brand. For me it’s shell T6.

I have no idea why I didn’t switch sooner! My brother is a professional heavy equipment mechanic and has preached to me for years that most manufacturers run Mobil Delvac oil. I have run Rotella, Delo, and lastly Amsoil in my previous engine.

Starting at 275,000 miles I switched from conventional to full synthetic and ran Amsoil 2 micron bypass filter and went to 30,000 mile oil changes with full filter changes every 5k and bypass filter changes every 15k with oil tests every change.

Well, at 346k I had a new 3000 mile HPOP go out, so I pulled the motor and opened it up to clean it. and all wear surfaces were going through (i do run my truck pretty hard, fwiw. I also then learned many racers have has AMSOIL ruin their engines).

I installed a new Jasper motor (regrettable) and I ran Delo for 20k. One day everything was sold out except Mobil. I bought it and only then did I notice it’s a SYNTHETIC BLEND!!! (can’t really tell easily) I was flabbergasted! What a bargain! It’s usually cheaper than Rotella etc conventional! The truck runs great, the oil looks good at 5k.

I wish I had switched sooner!!!!! (right now, June 2022, it’s $13/gal, $52/5 gal at TSC, usually $16/$62. Way cheaper than autozone, etc. Super bargain!).

My 08 Silverado currently has 1,176,894 miles on it. It’s never had any internal problems or repairs. It’s only had Mobil Delvac 1300 Super oil since it was new. I’d highly recommend this oil & plan on using it in the future.

I’ve been running Mobil Delvac 1300 Super for the last 12 years. 10 years in class 8 trucks and last 2 years in my Ram 6. 7 p/u. Never an oil related issue. I also run Mobil Delvac 1 75w90 in my AAM Differentials.

I use Mobil lubricants in everything I own.

This oil is great for cummins in cold winters. Gives great protection and still thin enough to work in extremely cold conditions

this is the oil recommended for my vehicle by GMC. very difficult to find locally but was able to order through Walmart and received it NEXT DAY, with free shipping.

I’ve been using this product now going on 15 years. Always have had great luck with it and the Wix brand filters. I use it in my cars and my motorcycles. We had -31 degrees the other day and my cars still started.

I go around 5 to 7,000 miles between changes. For myself, I choose T-6 first.

I use this product in my 07 yukon xl 5. 3 flex v8 after doing extensive research to fix a low oil pressure problem. I use the 15w40 for the higher viscosity and the research showed it had the best formula for high mileage vehicles.

I’m at 275K and rolling after 7k miles with highway turnpike trips all over Florida. I was about to get rid of the truck until I started using the T5. LOVE THIS PRODUCT!!! I would love to hear anyone’s feedback based on their experiences with switching to diesel oil in a regular oil engine.

I have a Ford 1310 tractor manufactured in 1984. This tractor has a small three cylinder Diesel engine and I have used Rotella T5 oil in the engine for the 3 years or so I have had this tractor. I like having a quality semi-synthetic oil in the engine to provide more high temp protection.

It gets very hot in Arkansas in the summer! I have had good results so far with this oil.

Good oil for diesels. I have started changing my own oil and greasing my Chevy truck because I cannot find anyone who will not put the right oil in when I take it to them. They hide and won’t let you watch the service and tear up shields and make you pay for them when they did it.

This was at a dealership in Kingsport. They have lost my business!.

This is a great oil for later model heavy duty turbocharged diesels that require DEF. Make sure to check the viscosity and ratings for your particular engine. I buy this for the three eighteen wheelers where I am a driver.

Maintenance on these engines is always very expensive in terms of repair costs and down time, so I do my very best to take good care of them. We have had no lubrication or emissions issues since I started using this oil in our equipment.

Prevention is the name of the game when it comes to maintenance and engine life. I use it in my own F350 6. 7 diesel too. I aim to postpone replacing my $10K DEF filter as long as I can.

I just changed the oil in my 2004 Dodge Grand Caravan and it loves it. Definitely seems to have more power and better response. HDEO in a mini-van? Crazy, right? No. If this stuff can stand up to the severe running conditions that heavy-duty diesels go through, then it can stand up to whatever my van is doing.

As someone who doesn’t have money to buy another vehicle or replace an engine, I want it to last as long as possible.

I have used Mobile One synthetic oil in my trucks since they were new. I have a Chevy with 247000 miles on original engine and never been touched other than to change oil and filters. I use this oil in my 2020 GMC Denali DURAMAX and it keeps the engine clean and performs very well in the extreme heat area that I live.

I recommend it for your Duramax. FWD II Yuma AZ.

So I’ve been a long time AMS fan but just recently I just sent off oil analysis on both of my diesel trucks. One being an OBS 7. 3, and the other being common rail 5. 9. Both having well over 350xxx miles on the clock.

That that being said the oil analysis came back absolutely perfect with the amount of miles The recommended by the manufacturer to be changed. The TBN was also perfect and Blackstone recommended that I go even longer on my next oil change.

This oil isn’t snake oil. It really is fantastic oil that not only does what it says but costs as much or LESS then your parts store oils you get. Of course you want to get it directly through AMSOIL for all their deals.

Other then that, I’m set to keep buying my oil from AMSOIL. Thanks guys.

I’ve been using Amsoil lubricants for decades. I’m loyal to the brand. I’ve been with Amsoil through the good times, and one of their bad times (back in the eighties). I’ve run Amsoil in motorcycles, cars, trucks, boats, high-performance engines, and factory daily drivers.

I have extensive experience in engine machining/building, and I’ve seen, first hand, how Amsoil provides performance and durability to engines that push their design limits. Recently I bought a 2017 F250 with the PowerStroke diesel, and I got to reading about the particulate filters, and how oils not approved by Ford could cause premature clogging of the DPF, and possibly void the manufacturers warranty.

Oils manufactured to the CK-4 spec initially resulted in premature wear in 2017 PowerStroke engines, so Ford released their own specification, WSS-M2C171-F1, and instructed owners to run CJ-4 oils until approved CK-4’s were available.

Since then several products have been approved by Ford for use in PowerStrokes, but concerned about the performance of the available CK-4 oils, and curious about how Amsoil’s Signature Series Max-Duty Diesel Engine Oil compared to them, I submitted a couple of samples to the guy who runs the 540 RAT Blog for testing.

The Amsoil product tested superior to all others tested to date, beat only by another of Amsoil’s own CI-4 spec diesel engine oil. I wasn’t surprised by that, based on my experience, but I was surprised to see a conventional CK-4 oil approved by Ford that also meets WSS-M2C171-F1, performed as well as Amsoil’s Sig Series Max-Duty, and costs about half what Amsoil’s product does.

I would love for Amsoil to explain why their product is still superior to that competing product, even though they performed so similarly in 540 Rat’s test. At thirteen quarts, half the price is quite a savings.

Is it really worth the price?.

I`m 70 years old was in the auto repair business for 49 years. involved in racing my whole life an currently drag race a challenger hellcat. I decided to forge the bottom end of the motor an could not believe how good everything looked inside the motor.

connecting rod bearings look like they just came out of the box. pistons an cylinder walls are perfect. but at the same time not all that surprised. always used amsoil an will continue to do so.

Previously, Shell included foil seals inside their bottle caps for Rotella so the purchaser could verify the contents had not been tampered with. When I opened my latest purchase there were no seals.

(Had someone used the good oil and replaced it with a cheap substitute?) I called the phone number listed on the bottle and was told Shell is no longer using seals but has gone to a cap which is supposed to split at the bottom the first time it is opened.

The split is very subtle and hard to detect. Might be a good reason to consider a more secure brand.

My 1979 Volvo 244 DL with 231000 km has been treated to Shell Rotella T4 10W30 since Sept. 7, 2019, odometer at 215477. The overhead cam/valve sound is quieter at 3000 R. P. M. on the 400 series highways at 100 km/h.

The rear crankshaft oil seal has stopped seeping oil this year. I used to use synthetic oil. I can experience that Shell Rotella T4 10W30 oil really agrees with the 2. 1 L, B21 A naturally aspirated gasoline engine.

These are long-lived engines, and anything I can do to prolong its life is appreciated. Thanks, Shell engineers, for the extra protection of Z. D. D. P. for the camshaft lobes!.

The only time I don’t shop at O’Reilly is when I can’t find a store or I’m not near one. By far the best store I’ve ever found is in Princeton where I live. There are several good people at this location but the best one that I have found that is extremely knowledgeable in every aspect is Blake! I was looking for a fuel pump that I couldn’t get anywhere for a 1995 Chevy 6.

5 diesel every location I called said they didn’t have it couldn’t get one couldn’t even find it. I called back to my store in Princeton and was lucky enough to speak with Blake he not only found that O’Reilly had it in stock.

He found it at a store that had already told me it didn’t exist and it was in their warehouse. I would prefer to buy everything locally but sometimes you have to buy stuff online especially when all the O’Reilly stores and all the other auto parts stores in town tell you that that fuel pump can only be purchased online.

So when he found it, that was awesome because he saved me from having more downtime waiting for it to ship, shipping costs, and I was able to buy it locally so any future warranties I have to deal with and I can go directly to O’Reilly in Princeton!.

This motor oil is a synthetic blend. It tolerates heat longer than regular dinosaur motor oil and doesn’t breakdown nearly as quickly as regular motor oil does. In other words, this oil protects my Peterbilt motor better than regular motor oil does and it does this for a longer period of time.

I always change the oil in my trucks. In my opinion, Mobil Delvac 1300 is a top quality brand ! Thanks for keeping out trucks up and running!.

This is without a doubt the best oil money can buy…I know Mobil 1 makes a good product…but Amsoil is way more advanced…lasts longer & breaks down slower. But of course that is only my opinion, buy it & try it yourself, you won’t be disappointed.

I changed the oil my self in my new 2021 GMC AT4 diesel engine. the folks at the help line were very nice to confirm i was ordering the correct product that met manufacturer’s specs. it shipped out very quickly.