Based on a few different threads and some other information I've read, I've become pretty skeptical on which full synthetics oils are truly synthetic. I know, that Royal Purple is a true synthetic and there are a couple more out there but, Mobil 1, as an example still contains some dino ingredients. I'm not saying it isn't good, just that it's not what it says by my definition, true synthetic. I also read a claim today at our local AAP that Castrol Edge is eight (8) times greater protection than Mobil 1. Here is some information I pulled up on the internet.
**************************
Castrol EDGE is an advanced, proprietary formula that provides performance and protection in extreme conditions such as towing, hauling, high and low tempuratures, rapid acceleration, and stop-and-go traffic.

Guaranteed extended drain interval protection for 15,000 miles, or one year, whichever comes first. Performance and protection that outperforms conventional, high mileage and synthetic blend motor oils.

API Service SM/SL/SJ/CF; ACEA: A1/B1, A5/B5; ILSAC GF4; GM4718M, GM6094M; FORD WSS M2C929-A
*************************
additional information from Castrol's website about EDGE:
http://www.castroledgeusa.c...gn=Castrol_EDGE#/faq

So, my question is, is Castrol Edge a true synthetic containing no dino oil or, is it another refined processed dino based oil with additives? Anyone? I think not.

Cliff, I just realized that I put this in Fiero General, feel free to move or delete it.

Ron

[This message has been edited by blackrams (edited 02-01-2009).]

Im perfectly happy with Castrol Syntec whether its full synthetic or not. It always has worked great, eliminated a few problems some of my cars had. Personally, I see no need for trying out something new. It eliminated ALL oil burning from a few that had minor usage, hot temp in the summer never shows much drop in pressure, even when towing. I go up to 10K between changes or 1 a year, so comes out to same cost in the end as regular oil.

Roger,
I'm really not questioning whether it good oil or not, not even whether it's better than another oil. What want to know and understand is whether or not it's a really and truly a pure synthetic. Or, is it still a blended dino version.

Ron

For what it's worth, regarding Castrol and their Syntec oil, the AMSOIL site specifically calls them out with this comment in their article about synthetic oils:

quote Not All Synthetics Are Created Equal: Please be aware that not all synthetics are created equal. There is wide differences in quality and protection provided by the various synthetics. Additionally, not all synthetics are 100% synthetic. Many are partial synthetics marketed under the perception of full synthetics to the unsuspecting consumer or even Group III hydrocracked oils such as Castrol Syntec, for example, which is a hydroisomerized petroleum oil and not a Group 4 PAO synthetic oil (there is a full article on this in our Informative Articles section detailing the battle between Castrol and Mobil). There are no PAO (polyalphaolefin) synthetic molecules in Castrol Syntec, yet because of legal finagling with the definition of synthesized motor oils they can legally be called synthetic. Basically, they changed the definition of a synthetic to fit the process of highly refining a petroleum base oil, called hydrocracking and fought with Mobil and the National Advertising Council to loosen the definition of a synthetic.

link to AMSOIL article in question:
http://www.performanceoilte...'sBestKeptSecret.htm

[This message has been edited by FieroFanatic13 (edited 02-02-2009).]

I just missread I guess, I thought you were wondering if you were going to have any advantage (like 'more' synthetic) than Syntec.

Looking at the Castrol website, It's hard to figure out for sure on the new "edge" line you're asking about. What a crock (the way they advertise I mean). Here is what they say- talk about industry speak and NO actual information being given to clarify anything. NOT ONCE on their own site do they specifically state that it's better "because it is a true Synthetic." Just comparison in performance. I'd say they answer the question for you in the second answer below (highlighted in orange):


In regards to why Edge is an "advanced synthetic oil":

"Unlike regular synthetic oils like Mobil 1 and Castrol SYNTEC, Castrol Edge offers extended drain interval protection, provides unsurpassed wear protection, and meets the industries toughest industry-agreed standards. Because of this combination of benefits we put in in a higher class of oil called "advanced synthetics."

In response to the question "Does Castrol Edge contain Polyalphaolefins (a.k.s. PAO's which are REAL synthetic):

"Castrol Edge is made from a proprietary combination of base oils, which includes PAO's."

[This message has been edited by FieroFanatic13 (edited 02-02-2009).]

The best and probably most expensive "true synthetic" is Amsoil. Amsoil was the first to manufacture a true synthetic back in the late '60s or early 70's; yes that was in the last century. Ed

------------------

Thanks for the responses, I do run synthetic in a few of my vehicles. I'm pretty happy with the results but, I really get tired of being led to believe something and then find out later that it depends on your definition.

Ron

(feel compelled to state affiliation when talking about oil. Amsoil Dealer)

Ron,

I have personally never sought this product out... but the German Castrol (which apparently is distributed and sold in the US) is a true group IV oil. I don't know how it is labeled or appears differently than the regular Castrol which is just a higher refined dino oil that Castrol sued in a US Court to use the term synthetic...

Anyway, there is a group over on Bobistheoilguy.com (think PFF... but about oil, not Fiero's) that swears by the German blend.

Just FYI... I gave up buying store synthetic when I found that I could pay the same for Amsoil at dealership prices... well unless you can find M1 on sale at Wally World in the gallon jug. Random tidbt... there is an increasing clamor that M1 has gone to hydrocracked 'synthetic' and moved away from their ester and ether roots.

------------------

<---- did you buy Cliff a beer?

Blake,
Thanks for the reply and the information.
See ya on the flip side.

Ron

quote Originally posted by FieroFanatic13: In response to the question "Does Castrol Edge contain Polyalphaolefins (a.k.s. PAO's which are REAL synthetic): "Castrol Edge is made from a proprietary combination of base oils, which includes PAO's."

I seen a commercial for Castrol Edge a few months ago, and started asking the oil experts I talk to about it; and we're all under the impression that it just has a little more PAO added to the Group III base stock. Castrol hasn't released any information which could lead anyone to believe that the new Edge line of Castrol is a true Group IV PAO synthetic. In fact, the only mention of PAO at this time, is in the FAQ in that question quoted above. You'd think that if it truly was a Group IV PAO based synthetic, they'd make it well known and not have anyone guessing as to what the actual base stock is comprised of. (We're still trying to find information on it though, as there's not a lot out there at this time).

If it truly is a Group III base stock with just a little more PAO added like we suspect it is, then it's HIGHLY overpriced at the $8 per quart that they're charging for it.

quote Originally posted by blakeinspace: II have personally never sought this product out... but the German Castrol (which apparently is distributed and sold in the US) is a true group IV oil. I don't know how it is labeled or appears differently than the regular Castrol which is just a higher refined dino oil that Castrol sued in a US Court to use the term synthetic...

There's not a lot of places in the US that sells German Castrol. Autozone is one place, and I hear that Pep Boys is another; although I can't confirm Pep Boys sells it, as we don't have one anywhere near here. If anyone is looking for German Castrol, (the only TRUE Group IV PAO based synthetic made by Castrol that you can buy in the US); then this is what you're looking for on the bottle.

German Castrol has "European formula" on the front of the bottle, and is only sold in the 0W 30 weight.



The back of the bottle also has "Made in Germany" written somewhere on it, as seen to the left of the UPC symbol.

[This message has been edited by Deabionni (edited 03-10-2009).]

Deabionni,
Thanks for the information/input. As I tried to indicate earlier in this thread, I'm not so much concerned about whether it's the "best" oil out there, I'm more interested to know if it's a true synthetic. It would appear that it's simply another higher refined Dino Oil. Quite frankly, I consider that false advertising. But then, I don't get to establish the legal definations.

Ron

quote Originally posted by Deabionni: German Castrol has "European formula" on the front of the bottle, and is only sold in the 0W 30 weight.

Dea... thanks for posting the photos! I'll check next time I'm at a Pep Boys for the German Castrol.

Being that I get most of my fluid and filter supplies from Amsoil now... I don't get to the parts store as much...
(that's both a good and sad thing)

quote Originally posted by blakeinspace: Dea... thanks for posting the photos! I'll check next time I'm at a Pep Boys for the German Castrol. Being that I get most of my fluid and filter supplies from Amsoil now... I don't get to the parts store as much... (that's both a good and sad thing)

found myself at a Pep Boys recently... they DO carry German Castrol... look for the 'European Blend' badge on the side...
If you insist on Castrol... get this blend. If you are paying extra for synthetic... might as well get the real thing, not the hydro-cracked.
BTW, it was the same price. ha!

Like I posted above... I don't need to worry about that by running the Amsoil, that's a beaker blended oil for sure... but many of the other big labels are not... So research what you buy. Even if you stay loyal to a brand, it is good to know the difference between a Type III oil and a Type IV/V oil... and get what you pay for.

------------------

<---- did you buy Cliff a beer?

I didn't know there was a 0W30 motor oil. Sounds a little thin.

Mobile ones a true synthetic ,,it is the low end of the synthetic food chain..

the many brands that claim to be synthetic oil are not,,BUT they are a great improvement over regular oil,,especially now that regular oil is $4.00 a quart

Synthetics were developed & born to give superior oil for german nazi Rockets and jets in big 2>> Synthetic oil is FAR FAR superior to regular oil ,,It is why all the major companies now have some sort of synthetic

there are higher grades than ams oil,, the purple stuff is close to ams oil,,I have not looked at the data in many years
AMS oil is the big boy on the block so there is some animosity towards it
Synthetic is slippery,, you can not break in an engine using synthetic ,, you use regular petroleum oil, then switch to synthetic..

Most of the original synthetic oils did not catch on ,, Redline comes to mind ./.
I will be using 5/40 castrol synthetic because I got it cheap..Im working up to it by flushing engine with 1000 mile oil change
ANY synthetic will help prolong engine life ,,it is slippery and sometimes leaks occur ,,sometimes synthetic soften seals better than hi milage oil or the products made to stop oil leaks ...
With an old engine ,,Do not switch to synthetic it will clean the engine,, and all the crud in the engine will be released into the oil..not good

[This message has been edited by uhlanstan (edited 05-12-2009).]

I have tried a few, and still find Mobil 1 to be a FINE selection.
Valvoline Synth - not so much
Castrol - even their blends - are good.

but, I just base this on how the oil looks & feels after draining out after 7k-10k miles
and Valvoline Synth SUCKED.
I have NEVER drained a pan of Mobil 1 which I didnt feel I could just pour right back in.
the Castrol Blends do seem OK - so I expect their full synth is liquid gold.

quote Originally posted by uhlanstan: Mobile ones a true synthetic ,,it is the low end of the synthetic food chain.. the many brands that claim to be synthetic oil are not,,BUT they are a great improvement over regular oil,,especially now that regular oil is $4.00 a quart Synthetics were developed & born to give superior oil for german nazi Rockets and jets in big 2>> Synthetic oil is FAR FAR superior to regular oil ,,It is why all the major companies now have some sort of synthetic AMS oil is the big boy on the block so there is some animosity towards it Synthetic is slippery,, you can not break in an engine using synthetic ,, you use regular petroleum oil, then switch to synthetic..

nice post Stan, I'd heard that about the Nazi's developing it first... not only for their rocketry, but also because they had to limited access to crude, so they devoted a lot of research into devloping slippery alternatives to stretch their supplies.

You're not quite correct on the not breaking in engines with synthetic bit... many cars come from the factory with synthetic in the sump. Vette and GTO are two that immediately come to mind. They also have a Mobil1 only sticker on the lfill cap... which annoys me, but hey... when you are the dominant player in the marketplace... you can do things like that. I wonder if Mobil1 paid GM for that priviledge or if Exxon/Mobil just gives GM free oil?

But back to breaking in engines... If it was a motor that I had built... I'd not break it in with synthetic, not so much because of the claim that it won't allow parts to seat properly, but more because, in a fresh engine, I am dumping the oil in the first 1000 miles to minimize the amount of heavy metals that will naturally occur during break-in... and draining synthetic oil with a short term OCI is just wasted money.

As for Amsoil and animosity... I think a lot of that is because Amsoil has the tragedy of having the first two letters of Amway... neither of which are related, but Amway has a huge negative image.

quote Originally posted by blakeinspace: They also have a Mobil1 only sticker on the lfill cap... I wonder if Mobil1 paid GM for that priviledge or if Exxon/Mobil just gives GM free oil?

I'd imagine its a business deal of some sort. I've tried to research it but have come up blank.

quote Originally posted by josef644: I didn't know there was a 0W30 motor oil. Sounds a little thin.

On the contrary, that oil far from being thin. Most 0W 30 and 5W 30 oils tend to be on the thin side of a 30 weight once they're at operating temperature. That's not the case with the 0W 30 German Castrol. In tests, the centistokes or cST (the oil's vescosity or weight) for the German Castrol is measured to be 12.1 cST at 100 degrees C. Most 40 weight oils measure around 12.5 cST at the same 100 degrees C. This makes the 0W 30 German Castrol almost as thick as a 40 weight oil once it reaches operating temperature. ~ Proof that you can't just go by the weight posted on the front of a bottle to determine the true weight of an oil; and those numbers should be used as a guideline at best.

To avoid repeating myself here, I've already covered German Castrol in this thread.

quote Originally posted by uhlanstan: Mobile ones a true synthetic ,,it is the low end of the synthetic food chain..

Correction: Mobil 1 is NOT a TRUE synthetic, as sometime around 2006 they switched their base stock from a Group IV PAO base to a Group III hydrocracked dino oil base stock. Strange, since they sued Castrol (and lost) for doing the same thing just 5 years sooner. That said, I wouldn't call Mobil 1 at the low end of the synthetic food chain, as Mobil 1 is still a very fine oil. It's just drastically overpriced for what it really is. Once again, I've already covered this topic more in this thread, so I'll post a link to save from repeating myself here.

quote Originally posted by blakinspace: You're not quite correct on the not breaking in engines with synthetic bit... many cars come from the factory with synthetic in the sump. Vette and GTO are two that immediately come to mind. They also have a Mobil1 only sticker on the lfill cap... which annoys me, but hey... when you are the dominant player in the marketplace... you can do things like that. I wonder if Mobil1 paid GM for that priviledge or if Exxon/Mobil just gives GM free oil?

Mobil 1 is printed on the oil cap because Exxon and GM have some interest in each other. It's in GM's best interest to promote an Exxon product like Mobil 1, as that puts extra money in GM's pockets. ~ Marketing hype at it's finest. (And a great example as to why you should do your own research and not fall for the marketing hype; as there's MUCH better oils available for the around the same money).

[This message has been edited by Deabionni (edited 05-27-2009).]

some people have 'blood brothers'

Deabionni, you're my 'oil brother'...

eww, maybe not...

I remember ELF being the best that I could find at a reasonable price, but they changed their name now, and I can't remember what it is.

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Red 86GT 4 Speed

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1999 GMC Jimmy 2dr 4x4
1988 Fiero Coupe
1986 Fiero Base Coupe..Steel Wheels Baby!
1986 Fiero Base Coupe...NO OPTIONS !!
1985 Fiero GT 3800 N/A (3800 S/C sitting on stand)
1984 Fiero Indy #1098 w/ centerline "Q" Wheels

Is it really worth spending $40 on oil for an oil change? I never really thought too much about synthetic vs dino oil. Does it help engine performance that much?

quote Originally posted by Riddick85: Is it really worth spending $40 on oil for an oil change? I never really thought too much about synthetic vs dino oil. Does it help engine performance that much?

Crud and build up in your engine is BAD, and synthetics not only help reduce these but they also hold up better under high temperatures and maintain their lubricating properties whereas dino oil often won't. You'll get varied answers, but the short of it is yes, synthetic is better. Do you NEED it? That is the $40 question I suppose.

quote Originally posted by blackrams: So, my question is, is Castrol Edge a true synthetic containing no dino oil or, is it another refined processed dino based oil with additives? Anyone? I think not.

Ask and you shall receive...

Castrol finally released the MSDS (US) and the SDS (UK) sheets for Castrol Edge oils sold in the US and the UK.

Castrol Edge 5W-30 - US

Castrol Edge 5W-30 - UK

If you look at section 3 on both sheets under "Composition/information on ingredients", you can clearly see that the US version is made up of "base oil - highly refined" which makes it a Group III (hydrocracked dino oil) synthetic. On the other hand, the UK version consists of "Synthetic base stock - Chemically modified base oil - Proprietary performance additives" which makes it a Group IV PAO based "true" synthetic.

Once again, Castrol in the US is only a Group III based (hydrocracked) synthetic; whereas the Castrol overseas is a Group IV PAO based synthetic. With Castrol charging around $8 per quart for the US Group III based Edge, I'd say that they're drastically overcharging people for what the oil actually is.

Right now, Castrol is taking direct aim at Mobil 1 with their "Think with your dipstick" advertising; claiming that Castrol Edge can provide up to "8x better wear protection then Mobil 1".



Of course the "8x better wear protection" claim is with using Castrol's testing, and any user oil analysis are yet to show up to tell the real story. To be honest, I'm very skeptical that one Group III based oil like Castrol could really offer 8x better wear protection then another Group III based oil like Mobil 1.

More proof of why you shouldn't buy into the marketing hype.

Here's another interesting tidbit, and more proof of why the weight listed on the front of the bottle is more of a guideline then a true testament of determining the actual weight of an engine oil.

Here's the data sheets for the (Group III) US Castrol Edge 5W-30, and the (Group IV) German Castrol 0W-30.

From the data sheets we can see the difference in centistokes (how thick an oil actually is) for both oils.

Castrol Edge 5W-30:
40C - 54.17 cST
100C - 9.8 cST

German Castrol 0W-30:
40C - 66.8 cST
100C - 12.1 cST

From the centistokes, we can determine that the 0W-30 German Castrol is much thicker at operating temperature then the 5W-30 Castrol Edge; and in contrast, the 5W-30 Castrol Edge is thinner during cold starts then the 0W-30 German Castrol. Logic would usually assume that the 0W-30 would be thinner at cold starts then the 5W-30, and they'd be about the same at operating temperature; but as you can see, that's clearly not the case.

In this case, the 5W-30 would offer better cold start protection, but with a cST of 9.8 Castrol Edge is barely thick enough to be considered a 30 weight oil. The 0W-30 German Castrol, on the other hand, is a bit thicker during cold starts (even though it's has a 0W when cold); but it's also thicker at operating temperature, and with a cST of 12.1, it's almost as thick as a 40 weight oil. (40 weight oil centistokes start at 12.5).

Hopefully, this answered your original question about Castrol Edge.

[This message has been edited by Deabionni (edited 05-28-2009).]

quote Originally posted by blackrams: ... I've become pretty skeptical on which full synthetics oils are truly synthetic ... Mobil 1, as an example still contains some dino ingredients. I'm not saying it isn't good, just that it's not what it says by my definition, true synthetic.

I think the major problem is that just about the only source of information on motor oils is marketing hype. How do you define "true synthetic?"

The idea that "true synthetics" are built up in the lab out of individual atoms of carbon, hydrogen, etc. is wrong. Virtually all automotive lubricants are derived from petroleum base stocks, as a matter of economics and availability if nothing else. "Conventional" oils are manufactured primarily by selective refining of the base stocks. "Synthetic" oils are manufactured by refining the base stocks, selectively fracturing the resulting molecules, and then recombining the fragments into engineered molecules that don't exist in nature, with specific properties not obtainable with simple refining. What results is a dumb marketing war: "Nyah ... Nyah ... Nyah ... My oil is more synthetic than your oil!!!" But marketing hype (as intended) obscures the fact that what's important is how the oil performs in service, not how it's manufactured.

That said, virtually all "synthetic" motor oils available today are superior to their "conventional" counterparts. The question for each of us is one of relative value. In normal automotive service, conventional oils are probably adequate for at least 95% of all vehicles as long as the oil and filter are changed regularly. Along these lines, motor oils labeled "semi-synthetic" are probably the best value out there; you get many of the advantages of a true synthetic but at lower cost.

Me? I consider the superior properties of synthetics to be worth the cost difference; I use Mobil 1 in our cars (including the Fiero) and generic WalMart synthetic in our (American-made) Honda lawnmower. Being air cooled, the lawnmower probably benefits most from getting a synthetic. It is 18 years old this month, has never required any engine maintenance whatsoever, and the oil still looks like new after a full season of operation.

[This message has been edited by Marvin McInnis (edited 05-30-2009).]

quote Originally posted by Riddick85: Is it really worth spending $40 on oil for an oil change? I never really thought too much about synthetic vs dino oil. Does it help engine performance that much?

To me, spending the money for synthetic oil isn't about engine performance, as much as it is about giving my engine as much protection as possible. The biggest thing to remember about Group IV and Group V "true" synthetic oils, is that they flow much better when cold, and resist sheer "breakdown" much better then their dino oil counterparts. They stay in their viscosity range much longer than dino oil, both in part because of their base stock composition, and the very stout additive packs that they contain.

Because of the base stock and additive pack that "true" synthetic oil has, it has a much longer service life then dino oil. (Which brings me to my next point). The way that companies process oil today is leaps and bounds better then the way they processed oil years ago. Today, your regular "run of the mill" dino oil should have no problem making it 5,000 miles between oil changes. That said, any Group IV or Group V synthetic oil can easily make it 8,000 miles between changes (without oil analysis), and even longer with oil analysis performed. An oil analysis will tell you exactly when the oil is becoming too contaminated, or the additive packs are used up and the oil can no longer be used.

Example: My Supra doesn't get driven very much each year (less then 8,000 miles), so I only need to change my oil once per year. If I was using dino oil in that engine, I'd need to change it twice a year and I also wouldn't be getting the same level of protection against sheer that I have with synthetic oil. The protection against sheer is pretty important to me in that engine, as I have a very hot turbo on that engine, which is doing all it can to help heat up, and brake down the oil that's in it. When you figure that I only change the synthetic oil half the amount of times that I'd have to change out dino oil in the same engine, then running synthetic oil becomes a no-brainer. I'm getting better protection for my engine, and in the end it's costing me about the same since I don't need to change it so often.

Our BMW 540i is the same way. If we ran dino oil in it, we'd be changing the oil every 5,000 miles; but since we're running synthetic oil in it, we should be able to go between 12,000 to 15,000 miles between changes (depending on how the oil analysis looks). So in the end, we're only changing the oil 1/3 to 1/2 as often as we would be if we were using a cheaper oil.

Synthetic oil: Better engine protection + extended oil life = no-brainer.

Gents, thanks for the information. I just hate being lied to and some marketing campaigns really push the line. Thanks again.

But, that brings up another question about synthetics. The ladies and I were sitting around down at the local singles bar talking cars, engine and automotive stuff, (Ladies Night) and the question was asked about using synthetics and the need to actually change the oil. One lady professed that she never changes the oil in her car, (runs the Purple stuff, a true synthetic I'm told), she just changes the filter every 3K miles and tops it off. She also claims she uses the best K&N filters. She claimed that synthetic oil never wears out and that as long as you change the filter and keep the oil clean, you're golden. Comments on this technique would be greatly appreciated.

Ron

quote Originally posted by Marvin McInnis: I think the major problem is that just about the only source of information on motor oils is marketing hype. How do you define "true synthetic?"

I already answered how I (and most people) define a "true" synthetic in this thread. In short, if it's not a Group IV or Group V based synthetic, then it's not a "true" synthetic; and is very overpriced for what it actually is, IMHO.

quote Originally posted by Marvin McInnis: Me? I consider the superior properties of synthetics to be worth the cost difference; I use Mobil 1 in our cars (including the Fiero) and generic WalMart synthetic in our (American-made) Honda lawnmower.

You do realize that WalMart oil is produced by Exxon (same as Mobil 1), right? Both are pretty good oils, but that said, Mobil 1 is a Group III based "synthetic", and not what I consider to be a "true" synthetic. I'm not saying that Mobil 1 is a bad oil, in fact it's a very good oil; but the fact that it's a Group III oil, makes it overpriced for what it actually is.

If you're persistent about running a Group III "synthetic" oil, you really should take a look Pennzoil Platinum "synthetic" oil. Just like Mobil 1, it's still a Group III based oil; but they refine it better with their hydrocracking process. Add to that the very robust additive pack that they put in their oil, and you're getting more oil for your money, IMHO.

quote Originally posted by blackrams: She claimed that synthetic oil never wears out and that as long as you change the filter and keep the oil clean, you're golden. Ron

Oil "wears out" through four primary mechanisms:

1) Depletion of the additive packages ... corrosion inhibitors, viscosity index improvers, anti-scuff agents, boundary lubricants, etc.

2) Mechanical shearing of the long-chain oil molecules into smaller pieces, resulting in lower viscosity.

3) Dilution and contamination of the oil by combustion products that migrate past the piston rings, along with that old devil, oxidation.

4) Particulate loading (especially severe in diesels).

Changing just the filter regularly definitely takes care of number 4. However, a full change of synthetic oil every 3000 miles would be insanely overdoing it. But consider that she's "changing" a quart or more of oil every time she changes the filter, so she's actually doing a partial oil change every 3000 miles. Since most synthetics these days are good for 12,000 to 15,000 miles between changes, she may actually be accomplishing the same thing incrementally. Bottom line, though, is that without performing an occasional oil analysis she will never know for sure.

FWIW, many years ago somebody (I think it was AAA, back when they were still an auto "club") did some long-term research on oil change strategies. As an extreme, they compared several test vehicles (NYC taxis were always favorite experimental subjects), some of which had their oil and filter changed religiously every 3000 miles, and some of which never received an oil or filter change. At the end of the test, the total cost of operating the vehicles was about the same. The "no change" vehicles didn't last as long (no surprise there) and were somewhat less reliable, but that was offset by the zero cost for oil/filter changes.

I have also heard from reliable sources that some (unnamed) car rental companies never change the oil or filters in their fleet of rental cars. They typically sell them at about 40,000 miles, when they're still under warranty, and they reduce their operating costs by simply never changing oil or filters.

[This message has been edited by Marvin McInnis (edited 05-30-2009).]

quote Originally posted by Marvin McInnis: Oil "wears out" through four primary mechanisms: 1) Depletion of the additive packages ... anti corrosion, viscosity index improvers, anti-scuff, boundary lubrication, etc. 2) Mechanical shearing of the long-chain oil molecules into smaller pieces, resulting in lower viscosity. 3) Dilution and contamination of the oil by combustion products that migrate past the piston rings. 4) Particulate loading. Changing just the filter regularly definitely takes care of number 4. A full change of synthetic oil every 3000 miles would be insanely overdoing it. But consider that she's "changing" a quart or so of oil every time she changes the filter, so she's actually doing a partial oil change every 3000 miles. Since most synthetics these days are good for 12,000 to 15,000 miles between changes, she may be accomplishing the same thing incrementally. Bottom line, though, is that without performing an occasional oil analysis she will never know for sure.

The best piece of advice for running extended oil drain intervals, is to have an oil analysis performed on your oil every 4,000 or so miles. I personally recommend Blackstone Labs as a great place to perform an oil analysis, and I'd also have them perform the TBN test (additional $10) for the first few oil changes; so that you have an idea of how long the oil lasts in your engine before the oil additives are used up. After a couple of oil changes, you should have a rough idea of how long the additive packs last, so you don't need to spend the extra $10 for the TBN tests once you have a base line to go by.

Without oil analysis, she won't really know for sure how her oil is holding up.

de... you on the BitOG forum?

BTW, if you guys would like to follow a history of lab results running long term Oil Change Intervals (OCI's)...
Here are my Blackstone Lab results of experimenting with Amsoil before I offered to sell it to friends or family.
Before analyzing synthetics... I was religiously under the car at 3000 miles... worried if the car would blow up on mile 3001.
Running an oil to 15k just about fried my brain. Huge culture shock.
Now I don't give it a second thought, I just check the dipstick every other month and top off as needed, and crawl under the car 1/5 as much! I've even got Blackstone urging me to run it on out to 17-18k... and I know it would still be fine, not only from the lab results, but because when I sent the sample in, the sump was about a qt low (I did not want to skew the results with recently added oil)... and a refresher qt really props up oil life.
Plus, a long OCI is cheaper and better on the environment (less waste oil).

The test vehicle is my Grand Prix GXP with a LS4 v-8.

UOA #1: 10k miles on Amsoil 0w-30 (old blend) from 13k to 23k on the odometer
http://www.clubgp.com/newfo...e=&smode=&s=#3848317

UOA #2: 15k miles on Amsoil 5w-30, from 23k to 38k on the odometer
http://www.clubgp.com/newfo...e=&smode=&s=#4543630

UOA #3L 16k miles on Amsoil 5w-30 with magnets and a filter change, 38k to 54k on the odometer
http://www.clubgp.com/newfo...e=&smode=&s=#4573253

UOA #4: 14k miles on Amsoil 0w-30 Signature Series, with magnets. 54k-69k on the odometer
http://www.clubgp.com/newfo...&p=1&tmode=1&smode=1

UOA #5: will be in about 15k miles running straight Amsoil Synthetic 30 weight
http://www.amsoil.com/storefront/acd.aspx
(and is what is in the car right now)

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<---- did you buy Cliff a beer?

quote Originally posted by blakeinspace: de... you on the BitOG forum?

No, oil brother, I'm not.

I've visited a few times, and even lurked there quite a bit after picking up the Bimmer to make sure that GC met BMW's oil requirements; but I never actually signed up or registered.

Now that I have an "oil brother" over there, I just may have to register & spend some more time there.

quote Originally posted by Deabionni: Mobil 1 is NOT a TRUE synthetic, as sometime around 2006 they switched their base stock from a Group IV PAO base to a Group III hydrocracked dino oil base stock.

My original point, perhaps not very well stated, is that both Group III and Group IV base stocks are ultimately derived from petroleum sources. The process to produce the Group IV stocks is just more complex and expensive. Thus it's not strictly correct, and probably misleading, to flatly claim that one comes from petroleum sources and the other does not. Given the ambiguity and technical subtlety, it's not surprising that some marketing types will blythely exploit it to misrepresent their products and that of their competitors. That's what I meant by my "My oil is more synthetic than your oil!" marketing example.

The physical and chemical characteristics of the final motor oil product are far more important than the details of how they were manufactured.

[This message has been edited by Marvin McInnis (edited 05-29-2009).]

Again, thanks to all that provided input. I went to the Blackstone Lab site and requested their oil sampling kit. I'll pull a sample on my Dodge at the next filter change. Obviously, the whole point is to get the biggest bang for my buck. Oil that provides the best protection for the longest time and the best price. I just hate the idea of being lied to about this, maybe I've been too into the political things that last few years but the lying bastards have got me believing very little of what they say.

I know there will be some compromise of the three but there is a best practice and oil that will apply. I like and believe that synthetics are better and provide better protection over the life of the oil change intervals. Currently my Dodge Cummins engine gets it oil changed every 10,000 miles with a filter change at 5,000 miles and topped off with Mobil 1 Turbo Diesel. I "think" this is a pretty good program but also want to look at the cost effectiveness of stretching the intervals to 15,000 mile oil changes and filter changes as necessary. That filter change could remain at 5,000 miles or may be pushed to 7,500 miles. I know the oil sample program will help identify the correct course of action. Used to sample vehicle and A/C oil and send it into the labs during my military days. No doubt it provides very useful information.

My Dodge rarely gets much city driving conditions, 95% of it's miles are highway miles pulling my gooseneck trailer. I think we all accept that highway miles are significantly less destructive on engines that city miles. Again, thanks for all the responses.

Ron

^^^ I'd stick with changing the filter out every 5,000 miles. (We change ours out every 4,000 miles). Reason being, you know that the filter is still "fresh", and doing it's job of filtering impurities out of your oil; but the other added benefit comes from the oil added when you top off your oil after changing out your filter. By topping off your oil, you're also adding more additive packs with the new oil added; so you're helping to keep your additive pack replenished, and helping to ensure that the additive packs aren't being used up during your extended oil change intervals.