I was going to stay with conventional motor oil but the more I read about synthetics the more I think it may be the better choice for my new truck. I never thought I would spend so much time researching about motor oil (I never thought I would spend so much time reading about diesel trucks either). Looks like there are several brands of synthetic out there so I narrowed it down to what I can buy locally.

No particular order:

1. Amsoil 15w40 Heavy Duty Diesel and Marine
2. Mobil Delvac 1 5w40 full synthetic diesel engine
3. Shell Rotella T 5w40 full synthetic

Any concern over 15w40 versus 5w40??

Are the Rotella and Delvac synthetic oils as good as the Amsoil 15w40? Does it really matter?

Does it all just boil down to using any diesel engine oil that meets the API specs of CH-4 and CI-4 and the rest is just marketing BS?

I would like to get 200,000 to 250,000 miles out of this engine before it needs to be rebuilt.

I have never gone more than 4000 miles before changing the oil in my vehicles. This will be a very tough habit to break. I know this oil subject is beat to death but I don't want to F*** this up. Thanks

In my opinion, you won't go wrong with any of those. Like you already know, just make sure it carries the proper ratings for a diesel.

I know it's gonna be a hard habit to break, but unless you drive like Mario Andretti, 4,000 mile drains is WAY too short. I went nearly 10,000 miles on my last drain with the Delvac 1, and oil analysis showed that the oil was in excellent shape and could have easily gone much longer. We have now moved my dad's '01 DMax to 20,000 mile drains on Delvac 1 based on the recommendations of Terry Dyson of Dyson Analysis.

I just did Delvac 1 at 3k miles, and I gotta tell you, it drives like a new truck. Wait a minute it is a new truck! You know what I mean, a differentm smoooooth new truck, and I have to say it runs cooler.

im using rotella 5w40. I just changed the oil and it was just starting to turn black. i meant to change the filter at 3k but forgot, didnt look like it was a big deal though. oil change was at 6k

I'm very interested in this thread. My Dmax has 8000 miles on it and I will be changing the oil in a couple of months. For the last 25 years I have used nothing but synthetic oil. My Jeep 318 has 196000 miles on it and still runs like new with Mobil 1 changes every 6000 miles.

Delo 400 seems to be highly rated around here but I think I got to try the syn in the Dmax at least one time to see for myself. If it runs cooler on syn that's very good. I had a 1967 Jaguar E type that ran lots cooler when I put Amsoil syn oil in it. At that time the Amsoil quart weight was greater than dino oil. It was more dense and could therefore remove more heat from the motor. I recently comp. the weight of Mobil 1 truck and suv with a quart of dino and they were the same. So any reduction in heat would have to come from less friction - right?

I'll post my observed results after using synthetic but as these posts seem to show, every Dmax is different. Most likely you will get the same life out of your motor using Delo 400 as you would using the premimum priced synthetic. This is just my conclusion after years of reading.

Happy Motoring,

05 CCSB 4WD D/A Last 4 tanks of fuel average 22.2 mpg:)

I drained the original oil at 1000 miles and put in Delo 400.

Ed

No particular order:

1. Amsoil 15w40 Heavy Duty Diesel and Marine
2. Mobil Delvac 1 5w40 full synthetic diesel engine
3. Shell Rotella T 5w40 full synthetic

Any concern over 15w40 versus 5w40??


The Amsoil and Mobil 1 are probably about equivalent. Personally, I'd give Mobil 1 the edge, but I couldn't back up that opinion with data if I had to.

The Shell "synthetic" is based on hydroisomerized petro basestock. IT's one of those Castrol-esque "synthetics"...basically just a very high quality conventional oil.

You also might consider Mobil 1 Truck and SUV in 5W-40 (meets all GM specs, CH-4 CI-4). Walmart carries it for $20 for 5 qts. Best value for a top quality oil and easy to find.

5W-40 is fine, and will make for easier starts. As long as it's 40 weight at temperature, the engine won't care.

I bounced the synthetic yes/no question around for several weeks, before and after I picked up the new 05. Then my good friend Tom made the remark - "How long you plan on owning this truck?" It answered my question.:)

I have been using Mobil 1 in my 98 1500 for 86K miles, and in my 88 Caddy Eldo for 206K miles, and both run like perfect. 5K - 6K on the filter change,(WIX Filters), and fluid change every 4th filter. I'll modify that a little for the Dmax, as I put Mobile 1 SUV in at 1100 miles.

I average 11K - 15K miles a year on my truck - I am planning on 300K out of the Dmax, thats 20 years - I think that will work!
:exactly:

I had a long conversation with the Mobil tech's because I couln't find the Delvac 1, and they said the Mobil 1 Truck and SUV in 5W-40, is the exact same stuff just repackaged, and easier to find at Walmart.

I got mine at Wally World. Right next to the Rotella. $7.75 a gallon or thereabouts.

Ed

I went back to conventional 15w-40 after 30000 miles of mobil 1 use. No mileage mpg decrease, engine runs the same and oil consumption is still 0. I cannot tell the difference and cannot make it pencil out. I change my oil at 5K regardless of what oil I use.

I had every intention of switching to synthetic oil full-time in my Duramax. I have done numerous 8,000 mile oil analyses on Delvac 1300, Delo 400, M1 T & S, & Rotella T 5w-40 psuedo-syn. The only advantage that I have personally found while using a synthetic in a diesel is during cold-temp start-ups. If a synthetic oil will help my engine last longer, why are my wear rates the same (& sometimes better!) when I use a conventional oil?

In my experience, from an engine wear & longevity standpoint during normal use, synthetics are not needed (a waste of $ actually). Now if I were towing in a very hot climate, or seeing a lot of sub-freezing start-ups, I would recommend differently.

JM2C :blahblah:

Amsoil synthetic for 5 years in all of my vehicles(1989 S-10,2002 Tahoe, 2003 Silverado,2005 D-MAX 2500HD) good piece of mind for me.Oh almost forgot 5000 miles at every change.

Just a little FYI...I stopped in my Chevy dealer yesterday. This is the oil they use for all Duramax oil changes. The parts counter person said it was Mobil oil.

Maybe the GM/Mobil oil is all I need...oil confusion is setting in :confuzeld

When i was searching for which oil to use, i was leaning towards amsoil. Then i found out it wasnt API certified. Is is still not? I'll pass on possibly voiding my warranty.

I after to much thought and research :cookoo: I have decided to stay with a conventional motor oil. I learned that the dealer where I purchased my truck uses Mobil Delvac 1300 Super 15w40 which meets the API CI-4, CI-4 Plus and CH-4 and several other specifications and approvals.

http://www.mobil.com/USA-English/Lubes/PDS/NAUSE2CVLMOMobil_Delvac_1300_Super.asp

I just returned from my dealer and I hovered over my truck while the service was completed. I watched the tech pour the Mobil Delvac into the engine (just to be sure it was Mobil Delvac). He installed a fresh AC/Delco oil filter, lubed the chassis and checked air pressure in all the tires.

Price of this service was $46.50. Oil was $2.01 per quart x10, filter was $9.84, the rest was labor and tax.

Mentally, there is no way I could wait to change my oil every 8000, 10000 or 12000 miles like I guess is possible with synthetic oil. I have always changed oil every 3000 to 4000 miles...I won't be able to break that habbit. I would always be wondering how my oil was holding up every time I got behind the wheel after 3000 miles. I am not going to have oil analysis done for piece of mind. My piece of mind will come from fresh Delvac 15w40 oil and AC/Delco filter every 3000 miles, have my dealer do it (he will then have records of it in the system), if there is ever a problem there will be no question as to what kind of oil I used, when it was changed and who changed it.

The most significant benefit that I was able to see after spending way to much time on this oil question is oil change intervals. Another benefit may be initial lubrication in very cold weather starting. However, I think with fresh, high quality, conventional oil and filter every 3000 to 4000 miles my oil will always be clean keeping engine wear in line with engines running synthetic oil. In Maryland we rarely get below 0 degrees. So the cold weather benefit may not be quite so beneficial to me.

I'm sure the numbers could be run to show a financial benefit to using synthetic oil in the long run. I just spent a whole lot of money on this truck, if I can't afford to spend a relatively tiny amount on oil and filter every 3000 miles then I have no business owning this kind of truck.

I'm happy to finally put this whole thing to bed.:clap: There maybe several who disagree and a few that agree. This decision just feels like the right thing for me. Thank you to all that replied to my initial post, this is a great website, one of my favorites:thankyou2

In my post yesterday with pictures of the GM Goodwrench oil, that is what is sold over the parts counter if you walk in and buy it by the quart. The parts person said it is Mobil oil. The oil that was used in my truck at the dealer today comes from a 55 gallon drum stamped Mobil Delvac 1300 Super 15w40. Just to clarify.

Those of you that said Rotella T isnt a real synthetic, Do you have evidence to back that up. I dont think API would allow them to mark it as Synthetic if it was just a good conventional oil. All of Shell's literature and the bottle says "Full synthetic."

Those of you that said Rotella T isnt a real synthetic, Do you have evidence to back that up. I dont think API would allow them to mark it as Synthetic if it was just a good conventional oil. All of Shell's literature and the bottle says "Full synthetic."

05DMAX...according to this it's a full synthetic.

http://www.rotella.com/products/rotella_t_synthetic.html

I doubt Shell wants to misrepresent their product.

I haven't heard anyone mention Royal Purple. I ran it in my previous truck (gasser) with positive results. I never did a camparison, but had intentions of running it in my 05 duramax after about the third oil change.

I'm a little concerned because no one on these forums seem to use it.

Is there any negative feedback for RP that I don't know about?

Changing any oil at 3 - 4k is a waste of time, energy, and money, and resources. I know you said you will never get out of the " habit" of changing oil at those intervals, but for one oil change do yourself a favor ( I did) and send in a sample of your oil at a 3k, change and see what they say, it will come back "good for continued use". Note, I'm not advocating synthetic OR Dino oil, just the fact that milage, age, or the color of the oil does NOT dictate it's serviceability, only a oil analysis will do that.
It's funny how when I had a contract for the dealer to do free oil changes for 70k miles, they had in the contract every %k miles, but when I had to pay for the oil changes it was every 3K , Hmmmm do you think something wa up with that. Now why would a dealer put in writing every 5k, if he thought it would hurt the engine that he would be resposible for.
Certainly you are free to waste your money however you wish. But, the service Manager at the dealer just told me last week, that 10K is ok with sythetic.

in my 93 Mustang I used only Mobil 1 synthetic.
It has almost 400,000 miles on her and still runing strong.
Original engine and Trans.

In my D-Max I use AMSOil Syn. has about 60,000.

...What percentage oil does it show before you guys change your oil.

ACE21, I agree, I put 40K on and manufactures buy back ( I was not going to put a dime in it) and pulled a oil sample and sent it in for laughs, and it came back good to keep using. Looks like the laugh was on me. On one oil change the thing ran like a swiss watch. The buy back was because it had body damage. The truck actually ran better than the new the replaced it with.
Will I ever go 40k, doubt it, but knowing I can is another story.

Those of you that said Rotella T isnt a real synthetic, Do you have evidence to back that up. I dont think API would allow them to mark it as Synthetic if it was just a good conventional oil. All of Shell's literature and the bottle says "Full synthetic."

Rotella T syn isn't a "true" PAO/ester man-made synthetic. It is a dino-based "hydrocracked" oil. But it is a 5w-40 oil, & that is the only reason that I personally have found, in my situation, to use a "synthetic". PAO based Mobil 1 doesn't get me any better wear results than Rotella "pseudo" syn. It all depends on your definition of synthetic, & there was a lawsuit between Mobil & Castrol over this.

Mentally, there is no way I could wait to change my oil every 8000, 10000 or 12000 miles like I guess is possible with synthetic oil. I have always changed oil every 3000 to 4000 miles...I won't be able to break that habbit. I would always be wondering how my oil was holding up every time I got behind the wheel after 3000 miles. I am not going to have oil analysis done for piece of mind. My piece of mind will come from fresh Delvac 15w40 oil and AC/Delco filter every 3000 miles, have my dealer do it (he will then have records of it in the system), if there is ever a problem there will be no question as to what kind of oil I used, when it was changed and who changed it.

The most significant benefit that I was able to see after spending way to much time on this oil question is oil change intervals. Another benefit may be initial lubrication in very cold weather starting. However, I think with fresh, high quality, conventional oil and filter every 3000 to 4000 miles my oil will always be clean keeping engine wear in line with engines running synthetic oil. In Maryland we rarely get below 0 degrees. So the cold weather benefit may not be quite so beneficial to me.

I'm actually surprised that after so much thought & effort on your part with this oil question, that you're sticking with 3-4,000 mile OCIs. A $20 oil analysis will prove, without a doubt, that you can easily double that OCI (even with conventional oil), & additionally will give you an early warning to any fuel injector, air filtration, & coolant/head gasket problems that might be developing. And concerning cold weather starting, I personally would take a synthetic oil with 5k miles on it over a freshly-poured-from-the-bottle 15w-40 dino oil any cold day of the week. That's why I use a synthetic 5w-40 in the winter months, but use conventional oil the rest of the year.

BTW, I'm not trying to criticize you. Educate yourself, & go with what you're comfortable with. That's why I originally started doing oil analysis. To find out which oil was best for me.

Rotella T syn isn't a "true" PAO/ester man-made synthetic. It is a dino-based "hydrocracked" oil. But it is a 5w-40 oil, & that is the only reason that I personally have found, in my situation, to use a "synthetic". PAO based Mobil 1 doesn't get me any better wear results than Rotella "pseudo" syn. It all depends on your definition of synthetic, & there was a lawsuit between Mobil & Castrol over this.



Like I said, do you have any evidence to back that up? I'm a Rotella T Syn user and would like to see.

deadfurrow, if you have to pay 20.00 to find out your oil is good why not just change it every 3k or 6k whatever youre comfortable with. If you send in the oil 2,3,4 times however many it takes before they say change it, seems like to me that is a waste of money. maybe it evens out by changing the oil less, just my.02 though

Thank you Bullydog! I wondered why I was sending in $20 for an Oil Analysis... Never did before I got the Dmax...

Ed

i think it makes sense every once in a while to find out if there is anything wrong with the motor but not to see if you need to change the oil. when an oil company says their oil is good for 15000 miles then i might CONSIDER waiting that long, once again just my .02

Like I said, do you have any evidence to back that up? I'm a Rotella T Syn user and would like to see.

The #2 post in this thread (http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=004920) at BITOG is the best definition of oil groups that I have ever seen (if you can believe a guy from Columbus, OH.;) ). BTW, Rotella T synthetic is a group III oil. BITOG is a good place to start if you're looking for oil info.

deadfurrow, if you have to pay 20.00 to find out your oil is good why not just change it every 3k or 6k whatever youre comfortable with. If you send in the oil 2,3,4 times however many it takes before they say change it, seems like to me that is a waste of money. maybe it evens out by changing the oil less, just my.02 though

I certainly don't do 2,3,4 UOAs per oil change. That would be a waste of $ IMO, too. I started doing UOAs with ~35k miles on my truck at every oil change just to see if certain oils gave my truck better results. I haven't even sent one in for about 24k miles, but I just sent one in yesterday, since I'm getting close to 100k miles, & want to know if anything is going on before I run out of warranty.

I ran into this description of oil recently:

http://motorcycleinfo.calsci.com/Oils1.html

It's put together by a motorcycle guy, but he gets into diesel engines/oils, too. It's a bit lengthy, so have a full beer handy when you sit down to read it.

Joseph

The oil anaysys is not done EVERY time , yes that's a waste - do it to educate yourself on the oil you are using and how far you can take it. It's like changing light bulbs before they burn out, and no one on the planet can say when a bulb will burn out. That's what the oil analyses does it tells ( Besides the health of your engine) you how far to take your oil AND THAT SAVES YOU MONEY!
The selling point for me was when I was using synthetic, and I took my last truck in for air condtioning work before a vacation, and they automatically changed the oil with dino oil, so for the next 2000 miles I personnaly could feel the difference. The day I got home I put the synthetic back in and and again it ran much smoother. Some people say, you can't "feel" the difference, well I did, and always have.
I just changed my 05 with 3k miles and the difference is amazing, and it's running cooler.

i could feel the difference just changing dino oils at 3k, i now have synthetic and it does run smoother

deadfurrow - makes sense, just the way you said it made it sound like you checked and checked to see when you needed to change your oil

The #2 post in this thread (http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=004920) at BITOG is the best definition of oil groups that I have ever seen (if you can believe a guy from Columbus, OH.;) ). BTW, Rotella T synthetic is a group III oil. BITOG is a good place to start if you're looking for oil info.


Thanks, never really new about base stock numbers. I thought that I was getting screwed with the Rottella T Synthetic. I probably will continue to use because it seems to be very comparable to G-IV PAO base stock oils and is alot cheaper and easier for me to get.

These Mfg's install synthetics at the factory, they must know something.

Aston Martin
Bentley Amage and Bentley GT
Cadillac CTS, XLR, SRX and STS
Chevrolet Corvette
Dodge Viper
Mercedes-Benz AMG vehicles
Mercedes SLR
Mitsubishi EVO
Pontiac GTO
All Porsche vehicles

Yes. They know that localized heat in their motors will push oil temps to exceed 305 degrees. A synthetic oil is suited to these applications.

I used to be sold on synthetics - but a few key posts on bulletin boards changed my mind...

1. A GM engineer who posted on a motorcycle bulletin board - he helped design the GM oil life system and stated the reasons for the chevy vehicles you list above requiring synthetics. He also stated that extended drain intervals with synthetics were pretty bogus. The additive packages between synthetics and modern day dino oils are comparable - and the additive packages get depleted at the same rate. In addition, synthetics and mineral oils are equally susceptible to contamination (cylinder washdown, etc).

2. Someone asked whether to use synthetic or conventional oil on the shell rotella forum (shell corporate website). The shell engineer responded back that wear was determined by the additive package - not whether it was synthetic or not. He also stated that advantage of synthetic was cold flow and better tolerance to extreme heat (and that's all). So, in my rather mild climates here in oregon - no need for a synthetic oil...

- jeff

Just a quick .02 the engineers on these web sites are pointing out that the extended drain interval is about the same, however they do agree that in turbo charged (i.e. our Dmax Diesel) applications synthetics are a good thing as synthetic oil will not coke like dino will under the extreme temps experienced in the turbo.

remember it's only .02..

For me with tepms above 115 all summer and still over 105 this week, synthetics are darn near mandatory.
GM engineer or not, I only believe what I test, feel, touch and see, and 40k on a change is not bogus to me. Who knows how long it would have gone.
And, if this GM engineer designed the current system, then he should test his own system. I changed my 04.5 GMC LLY to synthetics, and after 12k miles it was still reading 50% till my next oil change, so looks like the engineer was allowing me 25K

Enigma -
In our truck we don't need to worry as much about coking the turbo because the turbo is water cooled. For example, the need to let the engine idle prior to shut down is supposedly non-existent with our truck.

Synthetic versus dino oil is a "coke versus pepsi" kinda argument; It'll go 'round and 'round with no answer that satisfies everybody; I am not saying what "the answer" is, I am just saying what "the answer" is for me...

Kendall -

115 degree outdoor temps would not push your oil into the temperature range that would mandate a synthetic for our trucks. Synthetics are needed when oil temps exceed 300 degrees.

As far as your oil "minder" reading 50% after 12k miles - it takes hours, rpms and operating temps into account. I can't think of any way where any of those variables could be input into any algorithm to tell you that you had 50% oil life left after 12k miles - something is not right here...

- jeff

My LLY, for my .02, goes for about 10.5k to 12k miles between oil changes, when the truck tells me. I use the synthetic, Mobil Truck and SUV from Walmart. Now I do run my truck in heavy traffic, lots of highway and off road a bit. As you can tell, I have 102,780 miles on my truck and I took delivery of it on 3/28/04 with only 12 miles on it. Highway driving I run anywhere from 70 to 95 most of the time. I do run it to 120mph every once in awhile, when it is safe to. I do tow things a bit from time to time and have about 2000 lbs of equipment in the bed of it.

Now I have to consider the temperature issues. I am in Miami currently and it is hot as heck. I must say, between using the proper oil, changing fuel filters every 15k miles, changing rear diff fluid every so often, when it is dark, changing the spin off tranny filter every so often and running stanadyne in the tanks, I have never had an issue. My truck never overheats, doesn't slip and the injector balancing reads within +1.0 nd -1.0, which is better than the manufacturers specs of +6 to -6, in drive and +4 to -4 in neutral.

Just keep an eye on maintaining your truck and your truck will take care you, hopefully. I am getting ready to pass this truck down to my employees and get me a new one. But I am waiting for the 07's to roll out and see what good things the general will bring us.

In our truck we don't need to worry as much about coking the turbo because the turbo is water cooled. For example, the need to let the engine idle prior to shut down is supposedly non-existent with our truck.

Synthetic versus dino oil is a "coke versus pepsi" kinda argument; It'll go 'round and 'round with no answer that satisfies everybody...

- jeff


ok I'll bite on this one “the need to idle prior to shut down is supposedly non-existent...” uhh yeah I'll agree and disagree with that one. Admittedly the General designed this vehicle for (and I hate to say this) Diesel dummies, so yes they built in some protective features. I also will grant you that today's turbo design is far better than those of just a few years ago.


However please consider this, when you shut your engine off you stop the oil pump thereby stopping the supply of oil. Ok that's easy everyone knows that... except the turbo! The turbo is still busy loosing all it's inertia from just being worked, yet you've just stopped it's supply of clean cool oil! Don't believe me, well next time you stop your engine get out of the truck real quick and listen. I bet you're going to hear a noise for several seconds (mine lasts upwards of 20 sec) that would be your turbo spinning down with no fresh oil being supplied. Now again I'll agree that new turbos are much better than they were, heck even oil is much better than before but dino oil will coke when it gets hot enough where synthetic won't coke period !


Just my .03 (I've raised my rates as fuel is becoming so expensive)Censored

I have had several vehicles with turbos. That is the main reason I use Mobil 1. The life of the turbo is greatly lengthened by preventing the "oil cooking" when the engine is shut down. This may be stupid, but I am running 5W30 in my Duramax. Fuel consumption dropped increasing MPG by 1. Currently, I get over 18 MPG on my 4x4 at highway speeds (+3.5 MPH-to avoid Smokey) in high heat areas (Kansas).

This may be stupid, but I am running 5W30 in my Duramax.

Yes, you are correct. That is stupid. I hope you mean a 10w-30 diesel-rated oil, & not Mobil 1 5w-30 oil for use in gasoline engines.:eek:

I remember reading the post of the GM engineer about synthetics and how he help develop the OLM system.

He did say..as Jeff mentioned...additive package depeletion is the issue.

He also did say that a turbo charged vechicle is a good application for synthetics...because of the heat localized to the turbo.

I let the OLM tell me when to change and that runs about 10k to 11K.

Again...what dispels the thought is excellent oil analysis from oils such as Delo 400 or Mobil delvac 1500 that seems to show that they are still holding up well enough to still lubricate the motor.

To each his own.

I spoke to a Mobil oil distributor about Delvac 1 and Delvac 1300. I had called him because I wanted to find a local retailer of Delvac 1. He said the Mobil Truck and SUV synthetic is the same thing as the Delvac 1. Wal-Mart carries the Truck and SUV for $20 for a 5 quart bottle. Wal-Mart also carries the Delvac 1300 Super (conventional).

Anyway, he went on to say that his large fleet accounts run the conventional Delvac 1300 in their diesel trucks. These trucks operate for 100's of thousands of miles on conventional diesel engine oil. If there was a real advantage (cost, wear and tear on equipment) in using synthetic oil I would think that these fleet operators would use it.
I'm sure the operators of these commercial diesel trucks who are successfully using conventional oil for 100's of thousands of miles know much more than I and a few of you on this website in regards to oil and diesel engine maintenance. I know my chosen change interval of 3000 to 4000 miles seems to short to many of you and the fleet operators do go longer between changes but as far as wear and tear on the engine I just don't see the advantage of using synthetic oil compared to oil like Delvac 1300, Rotella and Dello with their very robust additive packages. Like I said, if there was a real advantge to using synthetic I think the fleet truck operators would be using it. Synthetic oil may be more marketing hype than anything. Just my .02

Maybe not too stupid. I put 275000 miles on a cummins 1 ton oil field truck, traded it for a new cummins 1 ton with winch, poles, etc. for oil field use. It presently has 75000 miles. Both used 10W30 Mobil 1 gasoline oil, and had the biggest Bank's kit available. I have yet to have any engine related repairs. The duramax is a 2500 pick-up for business and personal use. Surely, the duramax is at least as good as the cummins. When I think of all the money I saved on fuel over the years, the mobil light oil makes a lot of sense to me.

Here is an article on the new delo-400 formulation - improved to meet new CI4+ spec....

http://www.chevron.com/products/prodserv/nafl/auto/content/promotions.shtm

A few quotes from this press release...

"Delo 400 continues to use ISOSYN technology, which provides equal or better extended drain capability and fuel economy as synthetic oils, but at a much lower cost."

Delo 400 is a hydrocracked group III oil. If Delo 400 were marketed by Castrol or Shell - it would be labeled a synthetic...

"Delo® 400 Multigrade heavy-duty motor oil is an industry-leading, premium-quality, "universal" engine oil that exceeds the performance requirements of naturally aspirated, turbocharged and supercharged diesel and gasoline engines."

FYI - they added a bunch of moly in the new formulation....

jeff

Maybe not too stupid. I put 275000 miles on a cummins 1 ton oil field truck, traded it for a new cummins 1 ton with winch, poles, etc. for oil field use. It presently has 75000 miles. Both used 10W30 Mobil 1 gasoline oil, and had the biggest Bank's kit available. I have yet to have any engine related repairs. The duramax is a 2500 pick-up for business and personal use. Surely, the duramax is at least as good as the cummins. When I think of all the money I saved on fuel over the years, the mobil light oil makes a lot of sense to me.

Interesting. What kind of oil change intervals are you running? I would think that on an EGR equipped Duramax, soot would thicken M1 5w-30 into a 40-50 weight viscosity in a pretty short amount of time. If you want to use a synthetic 30w oil, why not use something like Amsoil's 5w-30 Heavy-Duty Diesel Oil? It would have the proper additive package & shouldn't cost any more than M1. (I can't believe I'm recommending Amsoil :rolleyes: )

Oil changes are at 15,000 miles. I use WIC filters. I will look at the amsoil product. Thanks for the suggestion.

When was the last time any of us lost an engine to an oil related problem? I don't mean lack of it either. ;) It is amazing what engines will put up with and live. If you like syn than by all means run it, but it seems to me that quality maintenace and care will allow any oil with the proper ratings to give us a long engine life.