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08-19-2005, 04:38 PM
Does anyone double up the annual/10kMiles/16kKm services with intermediate oil changes. Are these engines prone to sludge would be the basic question, because Id expect synthetic oil to last the full interval without degrading.

If the engine oil should be changed between the interval is it worth using full synthetic, seems like the long life properties of it would be a moot point.

08-19-2005, 06:19 PM
I disagree with Jaguar’s 12K mile oil change schedule either using petroleum or Synthetic oil. I changed the oil after the first 1,000 miles (break in period) and then every 5K miles. I use only full synthetic Castrol syntec or Pennzoil platinum 5W-40. If you check these forums, you will find many threads regarding this subject. This appears to be a common maintenance schedule.
Jaguar does not use synthetic oil. I discussed this with the service manager when I purchased my X350 in 2003. He recommended that if I decided to use synthetic oil that I change over to it as soon as possible to prevent any problems with sludge building up from previous petroleum based oil. Synthetic will break loose any sludge that built up and will cause clogging. I provide the oil and Jaguar performs the scheduled oil change and service. Changing the oil often is a lot cheaper then costly engine repair. If you are not using synthetic oil, I would recommend an interval of 3K miles.

There is a skid plate that encloses the bottom of the engine compartment. Besides the bolts that attach it, there are also four torx screws. This would require not only the proper tools but also a lift or pit to facilitate removal. Jaguar also replaces the oil drain plug with the scheduled change as it has a rubber washer. Probably not a good idea to go to jiffy lube.

08-20-2005, 05:43 PM

The XK-8 forum has discussed this issue at length.

The consensus seems to be that 3,000 miles is the correct interval and that 5W-30 is correct for the winter and 10W-40 is correct for the summer.

Using a synthetical oil for 3,000 mile invervals is overkill.

The one thing that you do not want to do is switch between oil types. This will generate sludge and seal leakage issues.

San Diego Mac seems to be a lubrication guru and he presented some pretty compelling data for the use of heavier weight oils.

I live in Hawaii and it is summer all year long, so I use 10W-40 non-synthetic and I change the oil and filter every 3,000 miles.


08-27-2005, 12:21 AM
I bought an '05 XJR. I recently had my first oil change after 5K miles. I just assumed that Jaguar uses synthetic oil because the scheduled maintenaince program brings the car back after about 12K miles. Should I think twice about switching to synthetic here in NY at 10K miles? Or just keep getting oil changes every 5K miles (3K seems too soon since I put on 1200 miles per month).

08-28-2005, 01:27 AM
I'd switch to synthetic and change with synthetic every 5K miles. I've done that with my '04 XJR and my old '99 XJR.

09-06-2005, 02:58 PM
Factory fill is Castrol dyno oil, which is what the owners manual recommends for the 10k mile change intervals.

I've been using Mobil 1 synthetic, changed every 5k miles in my 04 VDP, which was recommended by my dealer and by many other independant sources I found. My dealer isn't getting rich by making this recommendation, as they charge me a reasonable price for the Jaguar premium filter and the labour, and have me supply the oil.

01-30-2006, 01:19 PM
As heretical as that may seem, it is true. Changing the oil too frequently results in higher wear metals in the oil. This has repeatedly been demonstrated by several of us that employ oil analysis to determine the state of our engine and its oil at different intervals.

The reason appears to be that contemporary oil additive packs employ time release anti-wear additives and engine components evidence highest wear for the first couple of thousand miles after fresh oil is put in the engine. The wear metals concentration/per mile starts declining--quite noticeably--after that point. It is best to only change the oil, assuming proper filtration (stay away from Fram oil filters, use Purolater, Wix, Napa), as the TBN (Total Base Number--a measure of the oil's ability to neutralize acids formed by combustion products) declines to a point (about 1 or 2) showing little reserve capacity.

On Jag's, with their quite large sump capacities of about 8 quarts, double most other cars, the OCI's (Oil Change Intervals) are easily double that of most other cars. There are several reasons for this, not just twice as much oil to absorb the contaminents and double the additives to deplete, but much lower oil temperatures that stress the oil far less.

I own both an '03 XKR and an '04 S-Type--both 4.2 Liter engines. I have been carefully monitoring oil longevity with oil analyis in both of these engines. Under different driving conditions.

Last July/August I drove the XKR from San Diego to Oregon, to Niagara Falls, New York, to Toronto, Canada, and then took the Trans Canada Highway across Canada to Mile Zero in Victoria, British Columbia, then back down the Pacific Coast to San Diego. All in all, over 10,000 miles in a little over four weeks, albeit in mostly mild temperatures. All of this on the same oil. There were times when the ambient temps hovered around 100 degrees F., but mostly in the 80's. Speeds were mostly 75-85 mph. Although the California Highway Patrol claimed their airplane clocked me at speeds between 87 and 97 mph. When I challenged this in court a few months later the Judge agreed with me that their method was inaccurate (it helped that I've been a pilot for over forty years, with thousands of hours in the air, and was able to demonstrate that the CHP pilot was woefully ignorant of many aspects of flying an airplane) and dismissed the ticket.

Blackstone, the oil analysis lab I use, determined that there was ample life left in the oil even after more than 10,000 miles (on dino/conventional/mineral oil--Pennzoil Long Life). They suggested I leave it in for another couple of thousand miles and sample again. I did not, and drained it, mostly because I didn't want to take a chance on voiding my warranty. Incidently, my wear metals were lower than normal for these engines based on their sample history from other owners.

Granted, this was not under common operating conditions, but it clearly demonstrates that there is no one OCI to be used in all engines in all conditions.

If you really want to learn something about oil, OCIs, UOA (Used Oil Analysis), etc., search for some of my posts on the XK8/XKR forum. I will soon be posting results from both my own UOAs and other XK owners to help us see the differences between different oils and OCIs.

01-31-2006, 11:01 PM
I'm not sure how heretical it is but, it's certainly don't make sense for a few reasons:

oil companies want us to use as much of their products as they can make us believe that we should ( reason why the 3months/3000 miles is mostly "pushed" by the oil industry)

If, as you said, there is credible evidences that the "time release" (that obviouly can't be based on time but on heat/pressure )anti-wear additives,are not released for the first 2000 miles, you will have to ask yourselve why the oil manufacturers would design a product that is 100% against their marketing/financial goals.

Being a free market economy, you can be sure that, if what you say was correct, a competitor will have come up with an anti-wear package that work from the beginning and corner the market by advertising how much better their oil is compared to the competition.

If the rate of metal particles in the oil is higher just after an oil change than after a few thousands miles, you should look for other reasons, for example not filling the oil filter with oil and consequently having the engine run "dry" for a few seconds until pressure can build up.

also, when changing oil and filter,a certain quantity of old/dirty oil remain in the engine so, technically, all metal particles in it will be suspsended/mixed with the new oil and after driving the car for a couple of miles you could analyze the "only 2 miles old oil" and come to the conclusion that metal wear rate was very very high just after an oil change when in fact the rate was/is very linear .

02-05-2006, 02:07 PM
This is good information here. We leased our 05 S-Type R last November and changed the oil every 5k miles (inbetween the 10k services) with dino oil. I provide the oil and buy the $19.99 filter and take it to my mechanic that I've known for 20 years.

Here is the thing I was worrying about. My dad got the car, and with the last S-Type V8's (2000 and 2002) he always took it in every 10k for an oil change. Including the first change was at 10k. The car ALWAYS had a noticeable whine after that. It did NOT have the same "roar" as it did brand new. My dad never wanted to change the oil, saying "they should pay for it".

I need someone to give their best advice if I should keep convincing my dad to let me drive his car over for an oil change every 5k. He hates to do it, but somehow I keep convincing him.

Are the supercharged AJ-V8's prone to sludge from not changing the oil every 5k? IF you wait til 10k, that is WAY too long in my opinion on conventional oil. You'd think since it was supercharged it would need even more extreme care right? Please someone give me an answer on this. I run Mobil 1 in my cars and change every 8 or 9k. Including my new LS1 engine. The Jag dealer told me not to put full synthetic oil in the engine. I don't understand why not, but never have since they said that.

02-05-2006, 06:37 PM
if you're not planning to keep the car after the lease expire, don't worry about it, it will be Jaguar's problem, not yours.

But if you plan on keeping it,I will certainly change the oil every 5K.

The time frame for an oil change is not,neither should it be, based 0nly on mileage.
The way you accumulate those miles is very important,as a result of combustion, moisture and fuel find their way past the rings and mix with the oil to form an acidic brew.
In order to eliminate this mixture (and consequently sludge)the oil need to reach a minimum temperature of 212*, short travel distance will not accomplish this task and therefore the oil need to be changed more often (5K being a good # for conventional oil)

Long freeway travel at moderate Rpm's is the easiest on the oil, short city drive being the worst.

As for not using synthetic in a modern Jaguar, the jag dealer is full of it,futhermore,as long that the synthetic oil meet the manufacturer minimum requirement (all good oils does, especially Mobil one that is a very good one) it will not void the manufacturer warranty.

My guess as why Jaguar do not use synthtic is very simple : MONEY

They pay for the oil changes up to 50K and consequently save quite some money by using conventional oil.

02-05-2006, 11:20 PM
I doubt he will keep the car, he never does. But since this is supercharged I dont know. The car is hardly ever washed, interior always a mess etc. He doesnt have a clue on how engines work and therefore never maintained an engine correctly. I take ASE automotive classes and it really gets me when I see a $65k car like that beat to [Oops!]. The supercharger generates a LOT of heat too and oil changes are a must. They have to be....

As far as how that car is driven, well I always drove it hard whenever I had the chance. He drives gently I think for the most part except passing.. 50/50 city highway mix. As for me, I redline the thing all the time. On the highway I shift it manually to 6500rpm every gear. Took it up to 130mph one time on a straight flat. Did donuts for a minute straight in an empty parking lot one day in the summer and also got 2 speeding tickets in that car over the past year. Took it to the street races a lot too. Beat every car it went up against including a 375 twin turbo lancer evo. I still have those pictures too, it was so much fun. Then the car was smashed and repaird $35k damage when a lady lost control on ice and slammed into the rear at 60mph when it was parked. It never drove right since that either, but oh well. Also the transmission slips a lot recently if you floor it before it hits 2nd gear. Its a very bad sound. I wish you could check the trans dipstick, but like all stupid Fords you cant.

02-06-2006, 01:40 AM
One thing I will mention though, and I forgot to post in my last post is that I ALWAYS drive it around for at LEAST 5 miles, even if I only intended on moving it 5 feet. My dad on the other hand starts it up, backs it out of the garage 10 feet, turns it off and goes back in the house. He does this at least 4 or 5 times a week all year (including the -10 degree winter days).

I also NEVER go above 3,000 RPM until the engine is up to middle hash mark (full operating temp). In -5 degree weather, he simply starts the engine, puts it in gear and actually skids out of the driveway. This pisses me off. I always idle the engine for 5 minutes before even putting it into gear.

Also he puts 87 gas in the engine when I tell him to put 93. I insist on filling the car when I can cause I always put premium in it. It does run noticeable worse with regular as the PCM has to toss back the timing a few degrees to account for the garbage fuel. guys wouldnt believe the way he treats the cars. This is the 3rd Jag and its treated as a beater. Every time. Because its leased...

02-06-2006, 09:50 AM
I change my oil in my 04-XJ every 5000 miles (8000kms) with Mobil 1 synthetic, but that is with the full blessing and recommendation of my Jag dealer. Since they don't even stock Mobil 1, they even encourage me to supply my own oil. I own my cars for the long haul, and so far my dealer seems genuinely interested in helping me achieve that goal.

I personally believe that one should change the oil every 3000 miles with dyno oil or 5000 miles with synthetic oil. If you want to go beyond that, I think it is essential to have your oil tested to determine what the optimum oil change interval is for *your* car and how it is driven.

The owners manual 10000 mile dyno oil recommendation, is for "normal" driving conditions. For most of us, we fit under the definition of "extreme" driving conditions, so the 10000 mile change interval technically doesn't apply. The warranty is void if sludge is found, regardless of documented oil change intervals.

If your dealer recommends against synthetic oil, then follow his advice or take your car to a dealer who does endorse your choice of oil, as in the event of an engine warranty problem, they are the ones who have to go to bat for you.

In any event, with 10000 mile dyno oil changes on a leased car, any problems are likely to borne by the next owner of car, as is the case of most lease returns. Sad, but a fact of life in our ever more disposable society.

02-06-2006, 02:02 PM
It is not true that your warranty is voided if sludge is found in your engine. In order to void your warranty the manufacturer would not only have to prove that the car was not serviced in accordance with their recommendations, but they would also have to prove that any failure was directly due to that cause of action (inadequate service). They would never attempt such a defense if there was documentation supporting compliance with their service recommendations.

In fact, Toyota, GM and Honda have engine designs that have resulted in unusually high sludge formation and they have all instituted EXTENDED No Cost Factory warranties to cover engine failures resulting from sludge.

Sludge formation in our AJ V8 engines does not appear to be a problem. The very large oil sumps/oil quantity employed in these engines adds significantly to the reserve capacity of the oil. Also, the very low operating oil temperatures of these engines, especially the oil cooler equipped models--all supercharged versions, and apparently, at least on the XK series, all 4.2 liter engined cars, keeps the oil temps at the MINIMUM desired temp, thus not subjecting the oil to the HTHS (High Temperature, High Shear) conditions common to such engines as the GM series used in the Corvettes and their ilk.

GM engineers, and bean counters, made the decision to factory fill and spec synthetic oil for those engines as a much cheaper solution than installing oil coolers with those engines. The synthetic oil was needed only for its ability to perform better under extreme HTHS conditions than dino.

Synthetic oil appears to offer absolutely no benefit over dino/conventional/mineral oil in the AJ V8 engine unless one is attempting to use very extended OCIs (Oil Change Intervals). Even under such circumstances, any benefit could not be implied and could only be determined through comparative oil analysis.

In fact, RAM Aircraft Engine builders have found a significantly higher failure rate, and they maintain very thorough, careful, comprehensive records on their engines, with the use of synthetic oil. Aircraft engines are rebuilt on the basis of the number of hours in service, at which time they are disassembled and carefully inspected. The revelations of these inspections are much more insightful than anything obtainable from the automobile fleet. Visit their web site for more info on this. They adamantly recommend AGAINST the use of synthetic oil.

My research with the AJ V8 engine has revealed that the maximum viscosity of 30 weight is more than sufficient in any non-racing application. It may also be sufficient in a racing application, but I have not researched that application. Using a lighter weight than the 15W-40 I originally used also results in lower oil temperatures.

The winter viscosity, i.e., 0W, 5W, 10W, is dependent upon the cold start temps and is the same whether the oil used is dino or synthetic. In my temperate Southern California climate, 10W-30 has proven to be the best choice for both my 4.2 liter Jaguar engines, both supercharged and naturally aspirated. (XKR SE and S-Type Sport.)

Bottom line, using a 0W, 5W, or even 10W - 30 weight high quality dino oil, depending upon the ambient cold start temperature normally encountered, employed in a 7K to 8K OCI is probably more than adequate for all but the most extreme conditions. Continuous sampling and oil analysis on both of my 4.2 AJ V8s has shown that 10K OCIs, using high quality (Pennzoil) dino oil, in these car's primarily highway application of 10 miles or more, in a temperate climate, is easily sufficient.

Extreme conditions would be such as driving the car for only a mile or two after starting it and then shutting it down until repeating the cycle several hours later. Stop and go freeway traffic would not be as extreme in our cars as in others because of the large sump capacities.

Extending idling at initial start up to "warm up" the engine has been shown to not be advantageous. It leads to higher insolubles in the oil and causes it to break down more quickly. Allowing it to run for half a minute to a minute to circulate the oil before loading the bearings would be good practice, as would then driving it gently for several miles until the oil temp has reached operating range.

The only true way to determine the best OCI for your car operating in your conditions would be to spend $20 for an oil analysis to determine the safe life left in the oil. All else is only, often misguided and misinformed, speculation.

The optimal OCI for your engine would not only eliminate wasting money on unnecessary oil changes and unnecessarily expensive (using synthetic oil when there is no need for it) oil, it would maximize the life of your engine by affording it the best possible protection for the life of the oil.

02-22-2006, 01:22 PM

02-22-2006, 01:28 PM
I have to say that I have seen a number of V8 engines with very large amounts of sludge.

As to wearing out your engine with too frequent oil changes, what are we talking about ? an engine that lasts 150,000 miles, 200,000 miles or forever?

I seriously doubt that changing your oil every 5,000 miles will make a measurable difference in how long the engine lasts. I have been changing oil for about 40 years and have yet to have an engine wear out internally.

Just my experience, I like to see clean oil on the dipstick.

02-22-2006, 06:44 PM
Vic, I agree with you about the 5K oil changes. Certainly a safe interval, and if any additional wear occurred because the anti-wear additives weren't fully effective during the first half of the interval, that wear would probably be miniscule. So, maybe the engine wears out in 300,000 miles instead of 325,000. :-) Pure speculation on the numbers.

And, better to change it too often than not often enough.

I've just been trying to make the point that the revered "3K Oil change" is really unnecessary and out of date.

Also, if the dipstick looked black, I'd change it too, and quickly.

Have you seen Jaguar V8s that have been driven more than a few miles at a time with much sludge?

02-22-2006, 07:18 PM
3000 is probably more often than needed, and you are correct in that no one OCI serves everyone.

I don't know the driving habits of most of my customers, so I can't
speculate on why some have a lot of sludge.

04-25-2006, 02:13 PM
it could be due to a restricted part or full load breather. If the crankcase is not venting adequately, this can cause sludge to build up in the crankcase.

Lincoln had this very problem with its small V-12, used in the Zephyr and Continental in the '30's and '40's. The crankcase venting "system" was a poor design and as a result, sludge would build up fairly quickly in the crankcase. It required oil changes at least every 1,000 miles. Most people didn't change it that frequently, so these engines often met an early demise as a result.

When restoring one of these it is easy to revise the crankcase venting so this doesn't happen.

99 XJ8

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