I was reading the owners manual for my 2003 2.5L Xtype. In the section about the engine it says that Jaguar does not recommend use of synthetic oil in their V6 engines. Why is this?

 

I can't answer your question. But think of this way how else could you come anywhere near getting 10000 miles on an oil change, surely not by using dino oil. Although I've heard many say that they've found dealerships using dino oil which doesn't make sense. I use Castrol Syntec and change oil every spriing. I also use a K & N filter.

 

Adam, this has been discussed over the years. The benefits of synthetic oil can be argued 20 different ways. If you feel that using synthetic oil is beneficial to you, then run it. It is not going to hurt the motor provided that the synthetic oil meets the minimum oil requirements (API certified and any others listed in the book). Members here have been running synthetic oil in their cars and there have been no problems that I can recall. Please note that synthetic oil is a finer oil, so, if you have any sort of leak on the car, using synthetic oil is going to make it worse as the oil can creep through smaller holes and flow more through any existing hole.

From my personal experience having tried full synthetic oil, I did not see any change in mileage or power that would make me choose full synthetic over dino oil. I am also a believer in changing my oil every 4K miles. Overkill, probably. But, I have never heard of an engine failing because the oil was changed too often. Plenty from the oil not being changed enough.

 

I use synthetic oil, Mobil 1 or Castrol Syntec. I usually change my oil every 6000-7000 miles.

 

I also use a K&N filter in my X Type. I have used them in a lot of cars I have owned and never had a problem with them. Of course the dealers tell you that they will damage your engine, but as I said I have used them for many years in
Audi's, BMW's MB's Porsche's and never had an engine problem.

Getting back to the synthetic oil issue, I also see no harm being done to a modern engine using this oil. I think Jaguar is looking backwards. I asked my neighbor who is a Ford mechanic at a large dealership and asked him what type of oil they use in the V6 engine. He said a Ford branded synthetic oil.

 

As thermo mentioned Adam, this is one of the most discussed topics on the forums, and we've learned to steer clear of any more of them. It typically ends in flames. Strangely, the same goes for the k&n filter debate.

Its a personal choice, intermixed with all sorts of test data and internet facts that often lead to finger pointing and non-productive debates.

A word of advice, let this one go my friend.

 

^ Thank you.

 

OK, but I am still interested in the oil business. According to the service schedule the Jaguar dealer gave me, service should be performed at 7500 miles or 10K miles, what it didn't say, way there are two different mileages for each service.

 

Adam, the reason why they list 2 different mileages is dependent on how you drive the car. If you do mainly highway driving (over 90%), then going with the 10K mile oil changes is the factory recommendation. Anything else is considered "harsh driving" and should use the 7500 mile oil changes. If you look at all the services, they all have 2 different mileages. Again, this is for "highway/light driving" and "harsh driving". So, how do you drive?

 

Going 7500 miles on Dino oil IMHO is a stretch, going 10K miles will ruin a engine, again IMHO.

 

Without getting into a thread locker and keeping this nice nice, do you have any hard evidence to back up this assertion?

 

Mikey, how long an engine will go on an oil change is relative to the amount of deposits that the engine is putting into the oil. There are systems out there that will allow you to go 100K+ miles between oil changes (yes, 100K miles). But, you have to have a special micro oil filter to remove any abrasives. You are still changing the filter every 10K miles along with the special micro filter. You also need to add in some detergents to the oil to replace what is destroyed due to the engine heat.

You will find that there is no one that will say that an oil is only good for XXXX miles. There are too many variables to make a blanket statement like that. Without spending money on having the oil diagnosed and the impurity levels determined from a fresh oil sample and then post oil change, to put a mileage limit on the oil is only a feel of the pants thing.

If you want more info on this, check out a site called http://www.bobistheoilguy.com. You will have access to more info about oil and filters and what is good, what is better, and what to avoid. This guy has taken a lot of time and personal money in looking up oil specs, having oil analyzed, etc to make these statements. While he is not a true expert, I would trust his word over a lot of other peoples.

 

Thermo,

I'm familiar with all that- I spent 30+ years in the engine business and have kept my interest in this subject and others alive into my retirement. I've always been curious about claims of something being 'the best', 'the worst', 'different', 'right' or 'wrong' with no evidence to back it up.

Jaguar clearly specifies a 10K interval using regular oil under normal conditions. I'd like to see proof (either way) that this interval is not appropriate.

I used to have customers second guessing my company's recommendations and was appalled at the flawed logic used in some cases. My favourite was some sort of conspiracy theory mixed with supposed warranty savings.

To reiterate, I'm not trying to stir stuff or get the thread locked, just looking for truth, justice and whatever that third thing was.

 

Mikey, it sounds like we are in agreement (for keeping the conversation going). You have more experience than I do when it comes to what the internals of an engine look like after much use. I base my oil changes off of what I have done in the past and giving the oil the color test (is the oil still fairly clear, does the oil look like molasses?). I have found with my engine that after about 4K miles, that is when the oil starts to make a marked change in color, hence my desire to change at 4K miles. However flawed it may be, that is what I use.

I will be curious what others seem to use as the basis for their oil changes. On the wife's car, I used the little computer that was built into the car (06 Chevy Cobalt). That had me changing the oil about ever 7500 miles. I figured if I changed it when the computer said, if I ran into any warantee issues, I could simply say that I followed what was in the book (said to change when the computer says to). I know that isn't a good answer, but at the same time, I knew that I wasn't keeping the car for a ton of years, so, if any damage occurred to the engine, it was going to be long after I sold the car when it would come to light.

 

A lot of good arguments. I believe decades ago it was recommended to change oil every 10k miles. But once turbo engines, high rev engines and seeing people work their car hard was it lowered. I have been used to every 3 to 4k miles on regular and 5 to 8k miles on synthetic. Sure it can be used longer. But it depend on your usage and your want to take good care of your car. To each their own.

 

When I was a very young kid around 8 or 9 back in the 50's my Dad had a Dodge and he had the oil changed every 1000 miles. Don't know if that was a requirement by Dodge or he just decided to have it done at that interval.

 

I went on a website called Just Answers and corresponded with a Jaguar tech and here is the answer about synthetic vs dino oil he gave me.

The engine was not designed for synthetic. The engine is pretty strong in your vehicle but synthetic oil has different properties and it thinner than conventional oil. For example there can be issues with the VVT (Variable Valve Timing) which works off of oil pressure.

He also wrote that Jaguar only recommends Castrol conventional 5/30w oil in the V6 engine for the Xtype.

 

Adam, sounds like dad was **** about preventative maintenance...or he just REALLY loved his truck.

 

That's just the way it was done back then. Not just your dad but everyone, and yes it was recommended with filter change every other oil change. I elected to change filter with every oil change and still do.

 

Bottom line boys..Jag wants you to have a worn out engine after so many miles..and the quickest way to get you into a new JAG or replacement of a new engine was to follow their **** poor maintenance schedule..Use Synthetic,(think of it as K-Y jelly vs sand)..It's good for reducing the demand on foreign oil and it has longer lasting properties that conventional oil doesn't..the JAG engine is built for either oil..the conventional needs changing more often is the ONLY real difference..but the engine loves Synthetic, don't let anybody **** ya otherwise..... change it every 7000 miles and your engine will last forever (almost)...

Think about what I said...We all have been down the road on this "Filled for life" bullsh!t when it comes to the Transfer case, Transmission and Rear Differential..Those that were foolish enough to buy that crap..ended up with Transmission, TC and rear end failures long before a normal car with normal fluid change intervals would have. (buying a used X with a good number of miles is already a hopeless case, your loss is soon to come)..the mountain of evidence is out there..Ignore JAG's little maintenance OWNERS MANUAL..it is bogus and will send your car to an early grave...I've had my 03 X from new and I have diligently and regularly changed all the fluids and lubes with top quality synthetics and it is perfect with nearly 80K miles now....At least that's my story and it is, what it is..