Hi
I have just bought a 2006 XJ8 w/48000miles - first Jag
It appears as the engine oil is required to be changed every 10000miles and the oil should be min per spec. API SL/EC, ILSAC GF-3 - this is not even necessarily synthetic oil. Is the dealers really only changing oil each 10k? and not synthetic? - when are you guys changing engine oil? - I would never run beyond 5k with regular oil.
The service manual calls out that engine coolant should be replaced each 5year or 150k - Is that what you guys are doing? - Can the fluid be flushed out and be replaced by regular non-Jag fluid -withput any negativ impact?
I will change transmission fluid at 60k and replace the plastic tray with the filter in it - after reading on this forum.
When should the diff. fluid be replaced - no interval is indicated? when are you guys replacing the diff. fluid? I would regularly replace at 60k.

Thank you in advance - I am a little mind-buckled
MTW

 

Yes, oil change intervals are 10K miles. This is becoming standard for most vehicles and some, BMW, are going to 15K. Think environmental, auto mfgrs are under pressure to create more environmentally gentle products and that includes any units containing petroleum products like transmissions and differentials. That said, and given the newest petroleum products, 10K is no problem at all. In fact, I've had oil samples tested at 15K intervals with plenty of additive package left.

Jaguar specifies dino oil and not synthetic because they offer free oil changes (at least in the US) and synthetic would cost the company a fortune. Everyone would demand syn oil if Jaguar specced it for their engines. There are no issues using synthetics which further extend the changes.

If you really want to do your car a favor and save yourself some money too, move to 10K to 12K to even 15K synthetic oil changes with one or two interim oil FILTER ONLY changes. I do about 12K changes on my own cars with two filter only changes every 4K miles. The refreshed filter scrubs the oil of any solids and further extends its useful life.

If you have any doubts about the change extension, consider taking an oil sample and sending it it for analysis. It is really not that expensive and you'll be assured the oil is not overextended. That, and you'll be doing something kind for the environment.

Good idea on the 60K trans fluid changes. You'll likely need a change then anyway simply from parts that start to leak by then on the 6 speed.

Diffs, I have seen them go forever on cars not raced, but if you're going to be hard on the car, I'd go every 50K/60K.

 

Stevetech thanks,:
I have never encountered this in the US before in the 4 years I have been here, but this is also a British car -all cars in Europe have min 10000mile intervals. Every other car in the US I have owned has had max 3750mile intervals, and I kind of just had assumed the US engine oil just were not good enough for longer intervals. All US repair shops have basically made it sound like car abuse when I would go 7500miles on synthetic.
Any thoughts on the engine coolant replacement intervals?
MTW

 

On coolant, your car is designed to use an OAT (organic acid technology) coolant. Only use OAT for coolant replacement or topoffs, do not use other types. Commercially, DEXCOOL (Prestone gray container) is the correct formula.

I like to change OAT a little sooner than 5 years/150K miles. I usually do this if I am replacing any hoses in the system, and they'll need replacing before 150K miles.

The oil change debate is a controversial one! Most people who say they change oil every 3K or 5K miles cannot give a technical reason why they do that when asked. It gets down more to "tradition". My Dad always changed the oil every 3K miles in his 57 Buick, so I do too in my 2005 Jaguar. Technologies, both on the engine development side and the petroleum side have changed significantly over the years. 3K or 5K change intervals is simply wasting oil. If in doubt, be sure by testing it.

In 2010 the argument for too frequent oil changes is more than simply saying "I can afford it, and it's cheap insurance." I don't want to come across as a "greeny", but we each either do our part, or we're part of the problem.

BTW, oil formulas and quality are industry standards so it's not accurate to think oil in the US is inferior. Oil companies brand their products differently in different countries.

 

I think you will find that apart from miles, there is a time limit of 1 year on oil changes. This tends to pick up cars with low annual mileages and short, low speed, trips which tend to be harder on the oil than bashing along the motorway, (or interstate !)

 

For me, oil changes have many factors to look at. How many miles on the engine, how old is the car, how do you drive, how many quarts does the engine hold, what type of oil do you use. I would not run a 95 cavalier with 150K miles for 10K between oil changes on standard oil. The main fact is you need to change it. The rest is what you are compfortable with, with-in manufacture's guidence. These cars hold close to 2 gallons of oil. So, 10k on a syntheic is possible, but if it takes you 2 years to reach 10k I wouldn't wait that long. I change my oil once a year, but I only drive about 4-5K a year.

 

Here in the UK (FOR DIESEL) its every 1 yr or 15k whichever comes sooner.
The service indicator on the dash messaging system illuminates when a change is needed (counts back to zero from 2000 miles in 50 mile increments) if before 1 yr/15k.
On diesels the service message indicator takes into account oil dilution ,types of journeys (short town,long motorway) and also how hard the car has been driven.
I do under 10k/yr but if I did 15k I would allow the oil change to run until then with todays modern oils like Castrol GTX Magnatec.

 

I agree with everything except the filter. Unless the filter is clogged and bypassing, replacing it does nothing. In fact, a used filter actually performs better in some cases once it has built up a little cake.

Eddie

I still do 5000 mile oil changes.

 

Drew,

I agree with you completely on these points, but the analysis doesn't end there. Additional considerations - where you live, climate conditions. Driving patterns, as you've said.

Short drives where the oil doesn't reach normal operating temparatures in a high humidity or constantly damp conditions is far different than mostly highway speed driving in an arid climate. One of the reasons for the time requirement oil change interval is that cars, even when allowed to just sit without running in a damp or humid environment will experience many cycles of condensation buildup inside the pan. oil and water are the first ingredients of sludge. Combine that with salty conditions in the air, even worse.

On the other hand, in the Arizona desert, they park airplanes for longterm storage with no protection other than dust covers. These planes sit for years and they experience no deterioration of metalic parts or oil related deterioration. This is why I suggest testing so you can be confident the change interval fits your average driving in your environment. In my case, I live in an arid and mostly high temp environment where my cars easily get up to op temps, even on short drives. I once left the synthetic oil in one of my cars for 15K miles (with two interim filter changes) and Blackstone labs test showed I could have continued another 5K miles and they recommended 20K changes.

 

I suggest using a synthetic engine oil and changing it and the filter every 7500 miles. Going too long can develop a sludge in synthetics. I have seen more than one engine that has gone 15K miles that have a bad sludge in the oil pan. I agree that the tranny should get a change at around 50-60K miles, the differential should be good forever as long as the oil level is up to snuff, it's filled with synthetic gear lube from the factory. Coolant is the biggy for me, neglected coolant can cause all kinds of problems and you can't look at it and see the trouble ihn all the little passages.. I change the coolant every 3-4 years with DexCool from Prestone. Watch out for sludged coolant in these cars, the heater matrix has been a plugging problem in some cars.

 

I live in Hawaii and the air I breath is mostly salt. Most
of my driving is in town where I stop every two blocks for
a stop light and my average speed is 11 MPH mostly braking
to stop and accelerating away from the light.

I have heard for many years the cheapest and best method
of prolonging engine life is good clean oil. I believe it.

I change my synth oil every 6 months at approx 2K miles.

The XJ8 tranny is notorious for failing at about 70K mi. I had
to rebuild mine at 55 K. I have heard from many Jag Mechanics,
that changing the oil and filter in the tranny every 10 k may extend
the life to the lifetime of the car like Jaguar claims. Since you can
only drain half the oil, a change every 10K would equal a complete
change every 30k miles. A little expensive, but really cheap compared
to a transmission rebuild.

I agree with everything that has been said about the coolant and diff.

But nobody has mentioned the brake fluid. It should be clear. Look at
it every couple of years and when it starts becoming dark it is becoming
corrosive. It will eat out the rubber cups and seals, especially in the master
cylinder. Suck out the oil from the Master cylinder with a turky baster and then
bleed the lines till the fluid runs clear. Replacing a master cyninder costs about
$700 here in Honolulu.

 

You should have a sample oil analysis done. It would be interesting to see what the impact of the salt air is which is one of the worst conditions, and I suspect 2K in six months would leave synthetic in almost new condition, even under those driving conditions.

BTW - brake fluid flushing was just discussed in a thread just a couple down from here.

On trans, you must be talking about the 5 speed. It only yields about 4.5 qts. on a drain, about half of total capacity. The 6 speed yields slightly over 7.5 qts. of the 10.5 qts, about 70% of capacity. So, it would really be overkill to drain refill the 6 speed every 10K miles. I've had success with 6 speeds doing a 50K to 60K drain/filter/pan/sleeve/refill cycle.