Synthetic oil: Diesel mechanic says no - Page 5 - PeachParts Mercedes-Benz Forum

75Sv1 · #61 08-12-2011, 07:38 AM

'There is no cost savings when using dino oil except the per-oil change purchase price. The number of which are greatly reduced with synthetic.
Over 100k miles
$1.50/qt, $10 filter and 3k miles= $683
$6.25/qt, $10 filter and 8k miles= $671

So even though the oil costs 4x as much at the point of sale, over time its cheaper. It also doesn't factor in the amount of time saved doing 13 oil changes instead of 34.
If you pay to have your oil changed, you can bump the figures up to $1363 and $931, a much more drastic savings.

Think of it like having a 16 gallon fuel tank on a car that gets 20mpg compared to a 21gallon tank on a car that gets 25mpg. You're paying less per fillup so to the casual driver it appears like they're spending less money, but over time they're still spending more.'

I think you missed the point I made. To be in warranty, you have to change your oil at specific milage points. So, if at 5K, then both 'modern' conventional oils and synthetic will manage that. I think some of the conventionals will go 7,500 miles if highway miles. So, at that point you are throwing out money. I do recognize that with synthetics you will save money by extended oil changes. I have preached that for years. I have used synthetics beginning in the late 80's, then constantly in the mid 90's. I do agrre, that in an engine in good condition it is smart to use synthetic oils. I do remember a post on BITOG, a guy had an engine run on conventional oil for over 200K. It looked clean. Just a bit of varnish. Now the Contour I had, didn't have much if any varnish, when I took of the valve cover. Again, it use pratically no oil in 7500 mile oil changes. That was on the 'Fake' synthetic.
Tom

compu_85 · #62 08-12-2011, 07:42 AM

Quote:

Originally Posted by otto huber

Just to make this a full blown, cut throat, no holds barred oil thread, are you saying that Rotella T6 is fake?

T6 is a group III oil. M1 is a group IV. Under US law both are called synthetic, and both will work well in your car.

Many modern cars engines run too hot for conventional oil, so the debate is moot for warranty claims: The car maker will give you a list of approved oils and you get to pick.

-J

Stevo · #63 08-12-2011, 10:24 AM

The way I understand it, "Mobil 1 and Amsoil are reputed to be the only true synthetic", Perhaps that can be confirmed or denied?

bustedbenz · #64 08-12-2011, 12:24 PM

Quote:

Originally Posted by ForcedInduction

There is no cost savings when using dino oil except the per-oil change purchase price. The number of which are greatly reduced with synthetic.
Over 100k miles
$1.50/qt, $10 filter and 3k miles= $683
$6.25/qt, $10 filter and 8k miles= $671

This is based on 7 quarts of oil, which must be for a 240D. So, maintaining that amount,

$1.50/qt, $10 filter and 5k miles = $410 (5k interval is what I use on dino, because the book says to)
$6.25/qt, $10 filter and 8k miles = $671.
100k savings for dino: $261

For a 300SDL which uses 8.5 quarts per change:
$1.50/qt, $10 filter and 5k miles = $455
$6.25/qt, $10 filter and 8k miles = $789
100k savings for dino: $334

I'll grant that MAYBE the owners manual in the 1970s for a 240D says 3k miles. By the 80s, I know for a fact that the 5 cylinder runs 5K intervals by manufacturer recommendation, and I suspect that the 4 cylinder book was updated as well though it might not have been; I'll look later. For the sake of argument, I'll use my 300SDL example since A) it uses the most oil, and B) It unequivocally runs 5k miles on dino. So, at 3k intervals on a 300SDL (2k shorter than recommended)

$1.50/qt, $10 filter, and 3k miles = $758
$6.25/qt, $10 filter, and 3k miles = $2104
100k Savings for using dino: $1346

bustedbenz · #65 08-12-2011, 12:28 PM

I'll 'fess up, just for the sake of argumental honesty. I just looked up the 1976 240D manual that's available online and it DOES say 3000 miles. So, my 5k miles calculation at $410 is irrelevant. Forced was correct, and for a 7 quart 240D at 3k miles, synthetic is a cheaper oil over 100K miles.

However, I KNOW that my 8.5 quart calculation is right for a 300SDL. So for a 300SDL, at 3k OR 5k mile intervals, dino wins easily.

ForcedInduction · #66 08-13-2011, 10:55 AM

Quote:

Originally Posted by otto huber

Just to make this a full blown, cut throat, no holds barred oil thread, are you saying that Rotella T6 is fake?

Is it sold by Shell?

Quote:

Originally Posted by bustedbenz

dino wins easily

Flat out nope. There is no situation where dino oil is a better choice.

otto huber · #67 08-13-2011, 11:54 AM

Quote:

Originally Posted by ForcedInduction

Is it sold by Shell?

Yes, Rotella is a product of Shell

babyjames · #68 08-13-2011, 12:07 PM

I'll cast my vote - like anyone really cares - for synthetic. Only one of my cars gets driven enough in a single year to necessitate an oil change at factory recommended intervals. The poor 124 sedan gets thumped on pretty hard. The wagon and the '83 sit around just begging to be taken out on a sunny day. With dino I'd feel it necessary to change the oil in all three every six months. With synthetic, I do oil and filter on the '83 once/year. The wagon gets driven a little more, mostly on the freeway, so it gets a complete oil change once/year and a new filter/topoff every six mos. The beater gets oil and filter every six mos. On a year in which we drive a LOT that car sees 6000 mi, 40-50% freeway. Running Lubro Moly or Pentosin 5w40.

Jay

Marvelicious · #69 08-13-2011, 05:38 PM

Quote:

Originally Posted by otto huber

Yes, Rotella is a product of Shell

Yeah, T6 is apparently group III. Its apparently the best of the group III oils, but still comes from dino stock. Ran across this on BITOG, and it was a quote from somewhere else, so take it with a grain of salt.

Quote:

"It is true that ROTELLA T Synthetic is Group III (not PAO) based, but you must keep in mind that not all Group III base oils are created equal. ROTELLA T Synthetic is made with Shell's XHVI base oil, which unlike other Group IIIs does not begin as distilled crude oil, hence of all Group III base oils, XHVI is truly the only one that can legitimately be called "synthetic." XHVI is a wax isomerate, meaning that it is made from the slack wax removed from distilled crude in normal solvent dewaxing. This slack wax is catalytically transformed (isomerized) and hydrofinished into a chemically pure base oil which rivals PAO in virtually every category. There are other "synthetic" oils out there based on Group III, but Shell's is unique in that it uses XHVI base oil. Chevron and Petro-Canada produce Group III base oils that come close to XHVI, but even though these oils are all hydroprocessed and utilize the same type of isomerization technology employed in the making of XHVI, they are not the same thing. Only XHVI is made from pure petroleum slack wax and its CAS number is 92026-09-4. The CAS number for the more typical all-hydroprocessed Group III base oils is 64742-54-7. If you want to know what your "synthetic" oil is made from, take a look at the MSDS and look for these numbers. (The CAS number for PAO is 68037-01-4).

In brief, don't be so quick to dismiss Rotella T Synthetic as just another "synthetic pretender." It's made with the same base oil as Shell's Helix Ultra, and everytime you see Ferrari win a Formula 1 race, that's the oil in the engine.""

As I said, a quote from a quote, but supposedly originally from a Shell engineer, for what thats worth...

I've heard some noise (perhaps someone here can confirm or deny for me) that some of the Mobil 1 products are group III as well. It'd really be nice to know what a product is when one buys it wouldn't it? Its very difficult to sort actual innovation from marketing speak. I'm willing to spend money on good oil at my parts store, as long as I get what I pay for. I'm not down with the Amsoil route, no offense to anyone, but their sales strategy smacks of pyramid schemes to me and I just won't have anything to do with it. If they want my business, put it on the shelf at Napa or O'Reilly's or wherever.

Orv · #70 08-13-2011, 06:02 PM

Quote:

Originally Posted by babyjames

With dino I'd feel it necessary to change the oil in all three every six months. With synthetic, I do oil and filter on the '83 once/year.

I always thought the "every six months" rule was based on the idea that oil in an idle car accumulates condensation, which can turn acidic. Is there something about synthetics that prevents this from happening?

Doktor Bert · #71 08-13-2011, 06:51 PM

Recently, I stopped using Rotella, Delo and Delvac altogether, since they launched the new 'LE' reduced zinc formulas.

Now I run Valvoline 20/50 Racing Oil in all our cars.

ForcedInduction · #72 08-14-2011, 10:46 AM

Quote:

Originally Posted by Marvelicious

Its apparently the best of the group III oils

Thats like saying bottled water is the best kind of tap water.

Quote:

Now I run Valvoline 20/50 Racing Oil in all our cars.

That oil is not suitable for a daily driven vehicle, its not diesel rated and will cause soot clumps (sludge).

vstech · #73 08-14-2011, 10:56 AM

Quote:

Originally Posted by bustedbenz

I'll 'fess up, just for the sake of argumental honesty. I just looked up the 1976 240D manual that's available online and it DOES say 3000 miles. So, my 5k miles calculation at $410 is irrelevant. Forced was correct, and for a 7 quart 240D at 3k miles, synthetic is a cheaper oil over 100K miles.

However, I KNOW that my 8.5 quart calculation is right for a 300SDL. So for a 300SDL, at 3k OR 5k mile intervals, dino wins easily.

the SDL needs 8.5qts per oil change?
odd. my 124 should have the same capacity, yet only takes a touch under 8 qts...

vstech · #74 08-14-2011, 10:58 AM

Quote:

Originally Posted by vstech

the SDL needs 8.5qts per oil change?
odd. my 124 should have the same capacity, yet only takes a touch under 8 qts...

oh, and somebody update the costs calculation to include 5/qt of mobil1 on sale at orilies (and heavily stocked up by me...

) and fram filters at 3.50each when bought on sale at pep boys two for 7.00 again, heavily stocked up by me...

bustedbenz · #75 08-14-2011, 03:25 PM

Quote:

Originally Posted by vstech

the SDL needs 8.5qts per oil change?
odd. my 124 should have the same capacity, yet only takes a touch under 8 qts...

That's what the book says; I've always put it in. But I'm not in the "Oh I never let mine get more than halfway between the marks" club; I let it climb right up to the top of the high mark on the stick and if it's two fingernail thicknesses over that I don't worry about it. Between a tiny amount of burning and a lot of leaking, it needs a quart by about 4500 miles (so I just run it out the rest of the 5K and watch it) anyway.

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