Well, whether all oils are the same or not, the problem is that the users have neither the information nor the expertise to determine what brand of oil is best for their application. You can look at ratings and specifications, but you must assume they are correct.
Paying more makes no guarantee of better product. And what the local Jag "expert", a bunch of grease monkeys on the internet, your motherinlaw, nor any other such group says has no validity. It is all just anecdotal.

 

How true- even more reason to follow what the OEM recommends in the owners manual and not try to second guess or out-engineer.

 

Without question, not all oils are equal.

The underlying problem is obtaining relevant information and critical evaluation of available information. These used to be base requirements in academic achievement.

There are two groups of people: those who want prescriptive answers, and those that are willing to decide for themselves based on research. The second group is a dying breed due to the educational system and the internet.

The internet has also brought two unwelcome traits to everyday life: disinformation and wholesale regurgitation of text word for word as given truths.

Given the above, those who do not wish to do the work should follow the written word of the vendor, while those who put the work into the task ought to be able to determine what is best for their own particular usage.

However, given that this is an automotive enthusiasts' discussion forum , it is natural that discussions arise about what might be better than the base vendor recommendation.

Given the very first sentence of this post, it is not open to anyone to post with authority that there cannot be a better option than the base vendor recommendation. That would be a logical fallacy. Again, the real problem is in the particular individual deciding for themselves what information is real and useful.

 

I would use it without hesitation.

 

I would like to point out that a lot of the diesel compatible oils are marketed as "HD" with the letters being subscripted by the vendor as meaning "heavy duty" and not as some people believe "heavy diesel". The oils are also API Sx rated, so they are specifically rated for spark engines by the vendor. Finally, at least one reputable vendor, Shell, touts an advantage for their Rotella HD as being eliminating the need to stock separate oils for spark and diesel applications in fleet management.

 

plums:
In principal, I agree. And there is SOME data available on such questions as viscpsity vs mileage, and lubrication properties vs. mileage for synthetics af a particular brand vs non synthetic. But, when you get into a decision to run Rotella in a Jaguar, where is the science? Sure, if you are buying oil in bulk and you are lubricating heavy equipment and cars, it seems like a good choice from the rating. But how do you extend that to a general recommendation?
There is a particular guy on a Land Rover forum who obviously has a lot of experience working on Rovers who regularly recommends flushing the engines by running ATF for a few hundred miles. Untold numbers of folks respect his knowledge of repair procedures for Rovers, and presumably take his advice on this highly questionable practice. Just because he has extensive experience repairing cars, how does that make him an expert on the use of a flush procedure? Does he keep extensive records on the life of the engines he has done? I doubt he has, and I doubt we can find any credible data on Jaguar engines run with one kind of oil vs another or even oil change frequency except that collected by Jaguar. So, until I see evidence of other data being more reliable, I will believe what Jaguar says.

 

My apologies gentlemen, but I take serious issue with the those who suggest we follow the Jaguar "recommended" service schedules blindly because they where allegedly composed by "engineers"

Really?

Jaguar suggests that I should never change the transmission or transfer case fluid on my X type because they are "sealed for life". If the life is 30k miles perhaps that is true. X types are plagued with transmission and transfer case failures. Those of us that do change the magical "forever" fluids usually drain out some nasty decomposed pitch black junk.

Some of these suggestions are based on an agreement with a particular supplier ( Jaguar claims you "have" to use Castrol on some new cars-and dino at that) or to make the new car more attractive to buyers who don't want to have to pop the bonnet to check any fluid level or who find an oil change every 10k miles appealing.

It's not bad to think outside of your maintenance schedule box

While it may be true the AJ16 engine will run on virtually any oil don't assume that it will run quietly if you use dino oil + the recommended schedule. It's pointless to get into the benefits of certain oils over others in XYZ applications under XYZ circumstances, but knowledge does not only come from engineers, but also from groups of people who use the application on the field on a daily basis. That doesn't mean go listen to every crazy person on the Internet, but use common sense and understand what the benefits of a truly high quality oil can do or can not do for your car.

 

As much as anything else we form opinions from our own experiences.

Me? I spent 30 years in the auto repair business. That doesn't make me an expert on motor oil by any means. But I can say that I've seen I-don't-know-how-many engines (of any make) running sweet as a nut at 150k-175k-200k miles and their owners gave no more consideration to motor oil specification than I'd give to what color socks I put on this morning.

OTOH I'm a very big believer (and, often, participant) in the feel good factor

Cheers
DD

 

I haven't worked as an engineer for an (auto)OEM, but did spend a dozen years or so working very closely with their engineers as an engineering mgr. for a Tier 1 supplier to several big OEM's including Jaguar's parent during their Jaguar ownership years. If you want to understand the "why" of things, a good place to start is to follow the money-trail. The engineers can occasionally sneak a "source-control" drawing in - but for the most part, the stuff we argue about here; Oil, other fluids, tires, etc. the engineer is responsible for a specification and perhaps a test-specification that will control how the supplier demonstrates compliance to the specification. Then the OEM's buyers (Procurement, if you will) are armed up with the specs and they source to the lowest bidder, (or supplier with best NFL tickets or what have you) But the specification is the only technical control exercised by the engineers. And let's not forget, their charter is that it damn-well better make it through the warranty exposure trouble-free, after that, it is perfectly ok for it to go to hell in a hand-basket, as far as the OEM is concerned. The other consideration in sourcing such items is that each vehicle produced must be equipped with them at the factory - 5 or 7, maybe 9 or 15 qts eng oil depending on the vehicle, 4 tires, several gallons anti-freeze, and on and on. If you can shave $1.00 per car off the cost...but you produce 500K of them per year....pretty soon it adds up to real money. So the engineer stomps into the boardroom and throws a snit-fit at the Finance guys that run the company because they are filling each engine on the line with "Sam's Brontosaurus Mash" instead of the "Dr. Purple's Magic Syntehetic Elixir" he modeled the spec on? Doubtful. Even if his testing proved there would be 0.005" more material on the bearing surfaces at 300K miles with Dr. Purple vs. Sam's. Still not gonna happen.

That behavior is a little more prevalent in my workplace now that I'm at an aircraft OEM - even so there are still specs and procurement still finds "low bidders" but engineering does have much greater control vs. in the auto industry.
\rant off
Ross, I guess I don't understand your incredulity? Rotella T6 meets spec SM and can't find the link just now but I recall reading in order to meet SM, (or any particular oil spec) you must also comply with its predecessors, so if Jaguar specifies 5w-20 - 20w-50 per spec SG or SH, why criticize use of a 5w-40 per SM? Looks like it is right there in the thick of the spec range. If you plan to run synthetic vice dino, it meets Mikey's spec of being the cheapest - at least around these parts, land of the turbo-diesel pickup. I use the same 6mm socket on the Jags and the diesel Excursion, after all. Actually both the Ex and the XJ take Mercon ATF, too....But I'll confess that I wouldn't dare use the same spark plugs on both!

In the very end, I think if you change oil and filter at least as often as specified in the manual and use new, clean oil within the spec range....and chuck a rod thru the side of the block...you can probably eliminate "oil change regimen" early-on in your search for root-cause of the event.

 

Spike:
My assertion was that in lieu of good data, we have no reason to not follow the engineers who might have good data. If you have good contrary data, by all means follow it!
Now, as to the transmission fluid. Fact is, Jaguar does recommend changing the fluid in an XJ6 box. I assume you are referring to the controversy about fluid changes in the X-308 box. To that argument, ZF reportedly NOW does recommend fluid changes, but even that has very little data to prove its value. Many X-308 boxes never had the fluid changed since they are serviced by the dealer, and there is no good data that changing fluid prolongs their life. In fact, the main failure mode of a ZF transmission, as reported here on Jagforums, is a result of A-drum failure casued by a leaking servo valve. It would be a stretch to blame either of those on failure to change the fluid.
I don't have any first hand knowledge of whether or not changing fluid helps prolong XJ-8 transmission life since I have changed mine. Mainly due to the "feel good" factor mentioned by Doug.

I do have good anecdotal evidence that changing engine oil at the recommended interval is good enough for me. I have worn out an XJ6 at 275,000 miles, a V-8 XJR at 265,000 miles, have a pristine XJ8 now at 175,000 miles, and a "new" XJR at 175,000 miles, none of which have had engine failures other than a head gasket or sensors, which can hardly be blamed on oil changes. The cars I say I "wore out' still run great- they just got too ugly for me to enjoy driving. So, I have no real proof that 10,000 mile oil changes are better or worse than other intervals but I have some pretty good indication they are OK. BTW, I run the crap out of all of the Jaguars. Thats why I buy them.

Aholbro:
I agree with much of your point about cost saving to a point, and I am glad for it. I can afford Jaguars becaus of it. I do not agree that all design decisions are to get to the warranty period. The 8qt oil sump, and the bedplate engine designs Jaguar uses aar ecertainly not low cost designs. And most legitimate cars go 200,000 miles or more these days, much more than any warranty period. Maybe you have a sour grapes attitude because of a lost sale due to a higher cost?

As to my "incredulity". The originator of this thread had come to the point of asking if he should return the Magnatec oil he purchased for Rotella in order to increas engine life. I agree that Rotella meets the spec recommended by Jaguar, but if I an incredulous, it would be that advice given him led him to believe that there was good data to believe Rotella would make his engine last longer. You might remenber that his only indication of possible engine sludge was dirty looking oil in the drain pan.

The "Feel Good Factor" is a good motivator for doing lots of things to your car. But when ther eis no good distinction between feel goods and good well proven practice, it cheapens the advice.

 

Ross my earlier statement was:

"Jaguar suggests that I should never change the transmission or transfer case fluid on my X type because they are "sealed for life". If the life is 30k miles perhaps that is true. X types are plagued with transmission and transfer case failures. Those of us that do change the magical "forever" fluids usually drain out some nasty decomposed pitch black junk."

I am referring to the Jatco gearboxes and transfer cases on the X types that are "sealed for life" to illustrate my point. Based on the condition of the fluids when removed there is more than enough evidence to suggest that a "sealed for life" transmission is more a "sealed until it dies prematurely". Flushing out dark sludges fluid is not part of any "feel good" factor. It's a huge reason why so many X types have failed transmissions and transfer cases. Not only does the sludge clog up the cooler but it also mechanically ruins the 9 valves in the gearbox.

Engineers and car companies, make mistakes all the time, and Jaguar seems specially vulnerable to these miscalculations . From tensioners that disentigrate to Nikasil engines that eat themselves up and sealed components that prematurely fail and V12's that set on fire, Jaguar owners typically (and traditionally!) have had to make workarounds and have to rig things for them to work properly and make them into the reliable cars they can be.

For me at least, common sense trumps any specified service schedule. 10k miles between oil changes is insane, as insane as "sealed for life" transmissions.

I am glad your plan is working for you though.

 

Actually , I do love beating a dead horse!:
My point is, data is important. You have presented data, that I assume is valid, indicating that fluid changes prolongs the life of a certain transmission. I assert that given data, VALID choices can follow.
But then you use that data to draw a conclusion about oil changes. Show some oill change data!

 

Although they do touch each other I really think that "Which motor oil is best?" and "Which service intervals are best?" are two different discussions.

Equally problematic, but different

Cheers
DD

 

Ross, Nah...always a "real" engineer - never in sales. Sorry if I painted with too broad a brush. Sure there are designs that far exceed the warranty coverage and that could be done more cheaply. I guess what I meant to convey, was that if an engineer were convinced that a particular oil, or oil-chg interval, for that matter, if employed, would fail to get the OEM past the warranty period...then yeah, THAT would be worth storming the boardroom over - after all, when a component fails, they will all turn to the engineer that designed it (or more appropriately, summon him/her to the 4:30 pm Friday blame meeting)

I'd just advise caution in ascribing altruistic values to an OEM's choice in consummable items and change intervals, having seen that in many cases it has naught to do with reliability or optimization of performance, but rather optimization of profit - why they make the cars, after all, not complaining at all about that. I'm a staunch capitalist...just saying it's not always a heresy to question them.

 

Ross,

I use the X type transmission data to assert that Jaguar recommended service is not Gospel to be unquestionably followed by owners.

On My X type and your XFR Jaguar recommends Castrol. Castrol dino on mine. As far as I am concerned they can take that recommendation and place it somewhere very unpleasant. This is more of a marketing agreement/gimmick to force naive owners into buying a certain product brand.

Data on AJ16 oil?-as I said earlier we all know these engines would probably run on cooking oil if needed, but there is more than a feel good factor, there are the benefits of a cooler engine, a quieter engine and less sludge. Now, if you want to argue that opening the engine up to replace chain dampers that rattle like crazy is cheaper than a lifetime of high quality oil, I might be hard pressed to argue that point, but its not just about "feel good factor". Even on the indestructible AJ16 there are benefits from using a superior fluid.

BTW Ross, how do you like your XFR? I tested a 2013 model earlier this year and quite enjoyed the interior and ride, I could not get over the exterior with the new look though, then I got laid of from work so it did not matter if the exterior looked like a Daimler limo, I just could not afford it.

 

I assume that you've done a series of back to back tests with several oils that enable you to make such statements?

If it can be demonstrated that using 'high quality' oil staves off tensioner failure or conversely, have evidence of 'cheap oil' making them fail it would be of great benefit to the site members.

I'm under the impression that the plastic tensioners failed simply because the materials used were not up to snuff and could not withstand the heat- nothing to do with a lubrication issue.

 

Hi Mikey,

Our tensioners are not plastic like the later V8 cars. The chain guides on the AJ16 cars rattle is directly associated to a lubrication issue.

I don't know what statement I have made that would require me to test oils back to back, but I have seen enough AJ16's, including mine, whose original owners went on the dino oil /7k mile ritual whose engines rattle insanely. Will the engine rattle on without problems for 400k miles? Probably.

Some people smoke and eat high cholesterol and live to be 105 . Others die at 40 from the same routine. I personally err on the side of caution and eat lots of Kale, workout a lot and watch my diet very carefully. On my cars I like the best proven fluids and frequently changing them and I recommend anyone else to do the same, but the issue at hand is not what we "like" but what effect it has on, specifically, the AJ16 engine. My data tells me that a superior synthetic oil in that engine will cause less sludge, prevent chain rattles and cause the engine to run cooler.

If one believes that dino oil has the same effect on your car than synthetic (or that eating Fast food and lard is the same as eating lean protein and lots of vegetables) then we are free to take that chance.

 

This:

and this:

If you've not done an A-B comparison, your conclusions are no more than a guess or as you put it, a feel-good.

 

My Jaguar owners manual for my XJS says to put "Bars Leak" in the cooling system periodically.....I guess they know right from wrong since they "engineered" that decision...wait on second thought I'll second guess that and just say NO. Intervals are great "base lines" but one has to consider age, ring wear, blow by and the byproducts of such on engine oil. How far do you drive, how hot, how hard, how close to redline etc. does it get fully up to temp and get rid of moisture? NO SIR, I will NOT go with the recommended "engineered" intervals and such...they are "recommended" not hard and fast, tried and true. Just ask all those XJS owners who put in or had their dealer put in that "bars leak". YMMV, literally

 

Spike:
Actually I am not in love with the XFR styling (I like the XK-V12, X-300, X-308 better!), and I have only driven it 3,500 miles or so, BUT HELL YES, I LIKE IT! It is fast, sticks to road, is comfortable. It can sure get ahead of the driver, if you turn off the magic stuff, though. I am finding it hard not to get in trouble with the GA Patrol, too.

I saw it at the dealership's used car lot when I went to buy some parts, and it was there a month later. It had 3,500 miles and had been a demo. Some friends warned me that a demo might have been "dogged" around, but in truth, I have to admit I have probably dogged it more than anyone would with a salesman in the car. They went about $20,000 off sticker and added back the "certified" used warranty for a reduced price , so I pulled the trigger.

I assume you realize it is not only Castrol but special, dealer sale only, super duper Castrol! Yeah, I hate that, but I am going to let them put that in through the warranty. Oh, and you are going to like this... The recommended oil change interval is 15,000 miles.