Any mileage difference running Synthetic?

[Dannyboy]

I have about 2500 miles on my 06 now and i'm getting ready for the first oil change. I was thinking about trying Amsoil Synthetic 10W-30/SAE 30
Heavy Duty Diesel Oil. Will this help my mileage at all? How long will I be able to go on oil changes with only light towing.

Thanks
Dan

[Ranch55]

That specific oil is not spec'ed to meet the Duramax specifications. The Amsoil 15W40 Heavy Duty Diesel / Marine oil is the correct spec. for the Duramax.

[DmaxMaverick]

Ranch55 is correct. While the 10w-30 is CF rated, the Duramax requires a rating of CH or later. They do have an SAE-30 Heavy Duty synthetic Diesel oil, but I would not recommend it for automotive/light truck use, especially in colder climates. That oil is designed for large, heavy duty industrial/fleet equipment, like big Cat's, Cummins, Detroits, etc. If you want Amsoil, the 15-40 Heavy Duty Diesel & Marine is what you need. I have about 100K miles on my '01 with it. Amsoil did have a 5w-30 (or was it 0w-30?) Diesel rated oil, but I don't see it listed anymore.

[LanduytG]

The Series 3000 5W-30 has better shear strenght than the 15W-40. But cost is about 40% more. As for economy increase I never make that selling point because I have never seen and increase, but many have. I would not count on it though.

Greg

[hapaschold]

tried mobile syn in my 04 powerstroke van, and didnt see any substantial increase in mpg.....

[BozDMAX]

This early in your truck's life, I would go to synthetic and add a bypass oil filter and do oil analysis to determine your change intervals.

Search the forums for bypass filter threads. Install is pretty easy and you can easily double or triple your change intervals by sampling. I suspect that replacing just the OIL lost when you change filters will keep your oil additive levels 'fresh' - in any case, the sample reports will tell you when it is time to change all of the oil.

result: better filtration AND less money!

[JeepSJ]

To answer your original question, you won't see enough of a change to notice. Going 100% synthetic, front to rear (engine, trans, xfer case, rear end) may net you 1mpg.

[mark45678]

To answer your original question, you won't see enough of a change to notice. Going 100% synthetic, front to rear (engine, trans, xfer case, rear end) may net you 1mpg.

Been there done that..... in average temps in Newengland I dont see any benifits.... If its really cold you should see some benifits. IMHO


My take on syn , cost more money up front and I am not the last owner of the truck...... Rotela t in my ride syn in the rear , change it more often and forget it.

[DmaxMaverick]

Even if you aren't the "last owner", I think it's still good insurance. Using synthetic lubes WILL increase mileage and longevity. The debate is, how much? Many cases will not show an increase that can be realized by the consumer. Consumer testing isn't scientific. The increases can be more easily seen where you operate in the climate extremes. If you only operated in HI, it would very minimal, with constant temps. The sellers of synthetics offer "scientific" evidence their product increases economy, and decreases wear. Non-synthetic sellers have not, and will not, make a statement saying synthetics do not do this. If synthetics weren't superior, you can bet there'd be a company out there with a statement about it.

Ask yourself a question. If I were looking to buy a used vehicle, and the current owner offers documentation, or a believable statement, that synthetic lubes were always used, would you consider that a valid selling point? Most would say yes, even if they don't currently use synthetics themselves.

If you are in the camp that believes you should invest only as much in maintenance as is neccesary because you "only keep the vehicle a short while", try this...
Use high quality synthetics throughout. Keep the records/receipts. Make a comparitive record of what the cost would have been without synthetics. When you sell, set your price, and add a "surcharge" for the added expense for the synthetics. My bet is the buyer will pay that amount, which likely won't be as much as you think now.

Buying a used vehicle is scary business. Any assurance you can give that shows the vehicle received the highest degree of care will sell itself.

[cowboywildbill]

DMax, I have been using the Rotella T syn. Blue jugs from Wally world all year round. Is this good? Or should I go with Rotella regular? Thanks.

[DmaxMaverick]

You're kidding. Right?

The "Rotella" subject is kinda' tender for some folks around here. I'll offer my opinion, though....

Regular Rotella is good, for dino oil. Rotella T is better. However, this is where the "tender" part comes in. Rotella isn't a true synthetic oil. Period. It can be called that because a court said it could. It is altered dino oil. Nothing else. That doesn't mean it isn't a good oil. I just don't like what this backward court system in our country allows. Frivolous law suits, etc., and I consider Mobil vs. Castrol in that category.

That being said, if you're still here, the maintenance is more important than the product you use. If you are diligent with your service, the higher quality of products you use is an added bonus. Optimally, a true synthetic would be best, but many folks feel the bite in the hip pocket. If you were to follow the synthetic lube manufacture's use directions (in most cases), the cost difference is minimal, if not less expensive in the long haul. It's just that initial cost scares most people. As far as longevity goes, I've seen the results of synthetics. In my experience, synthetic motor oil is superior, hands down. The oil doesn't break down like dino oils. It gets dirty. It can be safely used many times longer than dino oils, if it is filtered effectively. There will be a time when it becomes contaminated/diluted with other engine byproducts and needs to be changed. You can't (realistically) run it forever.

The old "change our oil at 3000 miles" is old news. Technology has brought us past that. I ran my '85 6.2 for over 500K with changes at 10K+. I changed filters twice per service interval. My 77 Mercedes 300D ran for over 300K, before the oil pump regulator failed and killed the engine. My wife drove it for 3 weeks with no registered oil pressure before it finally kept overheating. She finally asked me when I was going to fix that broken oil pressure gauge The valves started to seize in the guides. The teardown only showed heat coloring, no galling in the cylinders or crank/bearings. The engine was overhauled, using most of the original parts, with no machining done. Still running like new, 6 years later. I replaced the head gaskets in my '85 Blazer at about 280K. All cylinders still had "factory" cross hatching and NO ridge. I replaced the original timing chain, which had no more play than the new OEM chain, with the original sprockets. Call it luck, or good lube. I credit the synthetic lube. I have no luck with anything, so I have to be good, and do it right the first time.

My first experience with synthetic oil was in the early 80's while motorcycle racing in Washinton state. I switched to Amsoil 30w and immediately my mileage increased by more than 10%, ran cooler (air cooled 4 stroke), and was faster. Only the oil was changed, nothing else. I raced trail/enduro in the Wasington Cascade mountains in the fall/spring, and the coastal mountains in the winter. Many times, temps were around 0

[copperhead]

I have been using Amsoil 15w40 since about 500 miles. I didn't notice a mileage different but when the stealer did some work on my truck a while back, they installed some dino oil and I did notice a BIG difference in cold weather starts between the two.

[DmaxMaverick]

A note of interest....

I was doing some research on Shell motor oil products, and their marketing leaves some unanswered questions. They have several product lines, and use certain terms very carefully. Rotella T synthetic is called just that, synthetic. Other product lines for other applications use the term, as well. They also have a "Premium" line, and use the labeling "full synthetic", claiming the "full synthetic" is far superior to other lines, and carries a price much higher than their other synthetic labels. These products are not sold through normal chanels, but are available through select distributors on request. I've contacted them with a request for their definitions of "synthetic" and "full synthetic". Their reply should be interesting.

More research, and I find Castrol has the same labeling in their product lines. Apparently, you get what you pay for. I've found, there is no cheap "full synthetic", in any label.

It's all about marketing, which can be very deceptive.

[WILLYD-MAX]

Thanks for the great info dmaxmaverick... I ran rotella syn. in my 05 when it was new and then did an analisys and the viscosity went way up at around 7k on the oil so it kind of scared me a little on rotella so I switched to mobile full syn. and have been getting along great. The rotella syn did not do that on our 02. Maybee it was because my 05 was still breaking in I don't know. One other comment on synthetic oil... we don't think much about dropping $45 to $50 when we fill up on fuel, what is the big deal about spending that every 7k or so on oil. Just a perspective that helped me out.

[JohnC]

Rotella isn't a true synthetic oil. Period. ... It is altered dino oil. Nothing else.

OK, so does any one know how the end products differ? I mean, are we talking about the difference between a scratch baked cake vs. one from a mix? If they can start with dino oil and process it into the same hydrocarbon chains that "real" synthetics have, and it costs less, well, it works for me!

BTW, in the piston aviation world, Shell's "semi-synthetics" are mixes of dino and synthetic oils.

[JeepSJ]

OK, so does any one know how the end products differ? I mean, are we talking about the difference between a scratch baked cake vs. one from a mix? If they can start with dino oil and process it into the same hydrocarbon chains that "real" synthetics have, and it costs less, well, it works for me!

A "real" synthetic lubricant will not be hydrocarbon based, THAT is the difference. You cannot start with dino and process it into a "real" synthetic - you can process it into something that you can call a synthetic, but it is not really a synthetic.

[JohnC]

OK, I'll bite again. If it's not hydrocarbons, what is it?