Anyone have a plausible explanation why the 3.0 engines were designed to require 7 quarts of oil? I've always wondered about this but never thought to pose the question until now. I can understand 7 quarts required in the STR, but not in the much-tamer 3.0 engines....

Perhaps it's tied to the long-standing Castrol relationship with Jaguar. A way to sell an extra two quarts of Castrol at every oil-and-filter change....

 

Jon,

My take on it is that more oil in the system allows it to remain cleaner longer. Historically, Jaguars have had large oil capacities for their engines. As an example, both the XJ40 and the X300 I used to have had 8.5 quart oil capacities.

Mike

 

I believe all the S types have some form of an oil cooler. I'm not sure if this is true with the 3.0 but if it does then the oil cooler adds capacity therefor requiring more oil.

 

I just love conspiracy theories............

 

I wish ALL cars could hold more oil.

 

OK, I'll bite- why?

 

My old Alfa was a 2.5 liter V6 and took 7.5 quarts. Had over 200k miles on it and it still ran fine. I believe that the more the oil, the longer the motor lasts.

 

Mikey,

Stock ownership in Exxon/Shell/BP/Conoco/Wesson....

 

I know all of you think I am crazy, among other things, but I change my oil every 2000 to 2500 and I do not own stock. Use strictly synthetic. The car runs better and I feel gives me less or no issues when doing so.

And one more thing that drives me crazy when all of you suggest to follow the car's manual when related to adding fluids. Do you ever give consideration to the thought that, example in my case, the book was written probably in 1999? Why would I want to follow recommendations on oil, other then the amount, in this instance from something written back then? Do you consider Time frames, experience, testing, more trial and error, newer and better products etc might all play into the possibility current results experienced with a different direction could be better then what was originally thought?

Oh that's right, I did follow that book on never having to change my transmission fluid because it will last forever; and had to replace my trans. Could it have lasted longer changing the fluids at regular intervals, who knows because the trans did have its own issues, but it could have.

All I know is if I am on the table with the surgeon ready to cut me open and I see him following his 1999 guide on how to perform it, I am getting out of there fast.

 

Ok I will jump in on this one Mike.

My dd not joycesjag, holds 6 qts.. I also change the 710 right about the 2,800 mile range, that is when the trucks computer states about 5% 710, left before the 710 needs changed.

I have all service documents since it rolled out of the dealer. First owner (corporate) switched it to Havoline Full Syn on day one (every 2,800), next owner kept up with the Havoline at every 2,800 (documented). I am coming up on 150,000 miles. When I change the 710 at 2,800, the 710 comes out like the day it was poured in, golden. I like that and will stick to this!!!

Now I am not saying Havoline Full Syn is the way to go, but in my case, I am not going to rock the boat (or in this case "land yacht"). In Joyces Jag I still use Castrol 5w30 as called for by the book right around the 5-5,500 mark. That 710 is not golden when changed.

 

Runs better? How? Frequent changes might make YOU feel better, but again there's no evidence that the car could care less, one way or the other.

10K intervals are nothing new, revolutionary or unique to Jags. Our lowly 2003 Honda Civic has a 10K interval too...............

 

My guess as to why the AJ30 needs so much oil is that oil not only lubricates the engine internals and keeps the timing chain in tension (typical), it is also used to "drive" not one but two VVT devices. Some engine designers opt for oil volume over sheer oil pressure, which is the case of most Alfa DOHC engines I know of. Hot oil pressure at idle on those could read practically nil, but as long as the oil level was kept religiously where it should be all was well.

 

Aha! Scientific proof as to why more oil is better. An MIT thesis by a Ms. Baran that studied the effects of windage tray design. The Duratec 3.0 V6 was used as the test bed. One of the conclusions was that with 6 vs 5 liters of oil there was significantly less oil aeration.

Here is a link to the document:

http://dspace.mit.edu/bitstream/hand.../166145859.pdf


Sorry, but its encrypted, meaning you can download a copy to read, but you can't print or post it. Some interesting stuff on the Duratec oiling system.

 

Rick,

I'll be honest. I think you're wasting your time and money changing the oil on your Escalade every 2,800 miles, especially since you're running synthetic. But it's your vehicle, your time, and your money, so have at it....

I've always run conventional oil in all of our vehicles, and I've always stuck to an oil-and-filter change every 6,000 miles. I've never had an engine failure in more than 42 years of driving, and one of my cars (my first new car, the 1974 Datsun 260Z that I still miss so much) did more than 250,000 miles in the 13 years that I owned it....

 

An on-going thread on the Jaguar Forum UK sheds some interesting light: engine failures in the transverse mounted V6s may be the reason for increased sump capacity: Jaguar Forum.co.uk • View topic - How much oil does the 3.0 V6 take?

 

Or that the manual was written to cover the manufacturer's ***.

It's amazing that the same self righteous people who insist on "factory" don't apply the same "logic" to replacement tires. First, the factory says, for example, Pirelli model X in a specific size. Yet, those people will fit other tires because they are "superior" in some characteristic. And then to top it off, they don't run them at maximum pressure as called for in the manual when "non-oem" tires are fitted.

Seems like some very selective "logic" is used when it comes to oil/atf/coolant. Might as well be Kool-Aid.

Anyone so dogmatic about "the manual" need not visit forums. All they need to do is:

1. read manual
2. go to step 1

Anything else would be a waste of time.

 

Good show. Hooray for the good guys!

edit: Unfortunately, the paper is marred by poor grammar and spelling mistakes which decreases a reader's confidence in the material. It is also weak in that it contributes nothing new in terms of knowledge. It is also obvious from the terminology used that the author is not particularly knowledgable about internal combustion engines. For example, the repeated references to "sparkplug valves". Bear in mind that at some point, that particular Masters student may be employed by a manufacturer.

 

Have you ever torn an engine down before? How about several? How about several using different maintenance methods i.e. brake in's, oil types, OCI, (Oil Change Intervals), additives, plugs, drive cycles? I have, several times over. I can tell you that a vehicle DOES care how often you change the oil. Now I'm no Automotive Engineer, but it's what I've done my whole life. As an Airframe Engineer I do have a mechanical understanding, and a piece of paper that says so. lol I say that because you are always saying the OEM is better because they’re the pros. They are a business that must compromise the best for business. That is irrefutable in its self.

Now with that being said, most owners under most circumstances would be fine with 10k intervals, but that same vehicle under the same conditions would fare better with 5k intervals. But you'd be splitting hairs. Now if you spend a lot of time under load, or in dusty conditions, then you NEED to up the interval frequency. I've saw you post before about how you oil should never get contaminated but think blow by, that is a natural, inevitable and inescapable process.

I know you are not a layman, so I don't feel the need to go into any further detail. You are just very stubborn in what you know. Not a bad thing to be confident, but ignorant to state an opinion for fact.

 

No need to get excited- just asking (as always) for someone to provide facts to back up an opinion they've stated. It's the unfounded claims that usually cause oil, fuel, filters etc. discussions to get a little too heated.

My professional life was 30+ years with an aviation engine OEM in design, manufactuing, field service and overhaul. My car, motorcycle, snowmobile, boat etc hobby goes back to the mid 60s and I do all my own work so yes I've seen 'a few' engines. More importantly, I've seen how engines go through in-house and field endurance tests and how maintenance intervals are developed. Since you're in aviation yourself, I'm sure the term MSG-3 is familiar to you. One of my most notable career 'achievements' was collecting data to prove that a 'new and improved' synthetic oil was in fact an inferior product and a step backwards. The data supported a decision by your and my regulatory authorities to withdraw approval. As a side exercise, I started looking for evidence of 'synthetic oils' being of any long term benefit in cars other than change interval. I'm still looking, but that's a subject for the bobistheoilguy site, not here.

Back on topic- unless a person has torn down a sizable fleet of identical engines, in this case the 3.0L version, that have been regularly serviced with varying oil change intervals, and can link this variation in interval with specific wear patterns, it's pretty bold to say that changing the oil at one fifth of the recommended interval is 'better'.

It's now fairly common to see S-types exceeding the 150K mile threshold. Is there a known engine failure issue attributable to lubrication? From what I've read, most engines are completely undisturbed and have never been torn down. There's no assurance that any or all the owners changed their oil at a low interval. Maybe if these cars reach the 200K or 300K threshold, a pattern will emerge but until then...............

 

Maybe its because I light up a dobee every time I get in the car after I change the oil, I don't know....it just runs better . Seriously, All I can say is it just seems to me the engine sounds better and just feels better like its thanking me for taking care of it (no I'm not high now). What can I tell you, I love that car.