Greetings to all...........Wanted to pass along my oil analysis for my 07 XK. The car has 35k on the clock and the car is driven moderately. The analysis was done with Castrol 5-30w and had been used with a premium filter. The oil had approximately 7300 mi of use. Results showed slightly elevated wear levels and the tbn analysis (life left in oil) was basically gone. For this oil to go another 2500 mi. would not be realistic.

With all the hyperbole about oil changes, brands and many unfounded opions (my dad always did it that way etc) I hope this is helpful to the forum. I just changed my oil (-: Be safe.

 

Are you suggesting that we change the oil more frequently?

For my XKR, Jaguar suggests Castrol 5W20.......would that make a difference?

 

Very interesting! I have not heard of that test/analysis. It would be very interesting to see some qualitative results after repeating this test using different oils.

 

Interesting. I'm having my oil changed after 1 year and about 5000 miles. Hopefully I didn't do any damage!

 

Many years of experience in the aviation engine business demonstrated to me that the results of a single oil sample are almost meaningless. Too many false positives to be of much help.

Kinda like deciding on a heart transplant based on one blood pressure test.

 

Thanks for the info but you don't mention when the oil was last changed as I would assume time is a factor as well. According to the service schedule oil should be changed every 12 months or 10k miles, which ever comes first.

If the car is 7 years old and done 35k it is averaging 5k miles a year so unless you have started doing a higher mileage it should be due to be changed anyway.

I believe that short trips also aren't kind to engine oil. My XKR is a daily driver but only managed just over 3K miles last year because my commute to work is only 4 miles each way. Because of that I wouldn't dream of not changing the oil every 12 months.

 

Back in the 60's and 70's I would change oil every 3000 miles. As the quality of oil has improved I have evolved to every 5000 miles or 1 year. I still haven't gone past that strategy and even on my wife's 89 Volvo with 340,000 miles I still do a change at 5000. Needless to say with today's synthetic oils it could be feasible to go to 10,000 miles I am not there yet. Unless you are doing a 50 mile commute I feel there are to many variables that will contaminate the oil limiting it's effectiveness. So at this point the cst is cheap for a better feel of protection.

 

I completelt agree! Given the reasonable cost for oil, why not change it?

Wal-mart is selling a 5 quart jug of mobil 1 synthetic for only $25! + filter $10

I can comfortable live my life knowing I have probably wasted a lot of money replacing good oil but none of my cars suffer internal damage as a result.

So I'd rather waste oil than spend $1000+ rebuilding my engine.

 

I keep forgetting to buy better priced oil before my oil changes. I let the mechanic buy the oil across the street at Napa and I get a sticker shock each time I pay the bill.

One factor that should be of concern is the oil filter. How well does it actually filter above 5 or 7K miles?

I'd change the oil more often if the car was on the lift something else. I expect brake work this season, so perhaps an interim oil change too?

Our Range Rover (BMW V8), the oil gets dirty faster than the Jag; what does this mean?

 

changing oil "too early" will not harm your engine.

changing oil "too late"? dig deep, the damage has been done and it is irreversible without expensive surgery.

there is a "reasonable" gap between too early and too late.

 

Rubbish. Full synth can last perfectly well for 10k.

They just said that to make you feel like you got good value out of using their service.

 

Also, shorter trips, has a detrimental impact, as well. Change more often than recommended intervals.

Happy Trails......

 

Not so.

There are plenty of scanned Blackstone UOA's on bobistheoilguy where the conclusion has been "TBN good, try running for an additional XXXX miles this time".

Your accusation that Blackstone deliberately engages in the devious practice of fudging the TBN number is a serious accusation.

Just doesn't meet the smell test.

As the most popular testing service for consumer users, they have much to lose and little
to gain from such a practice.

 

Ideally, the engine oil should be changed with formula based on engine hours, start-stops, and miles traveled. How that is calculated, is beyond my math skills.

 

Usually when buying a used car I go through a oil change process to see if I can clean up the engine. I do not use these various engine cleaners on the market. What I do is drain and refill the oil. Run the car for 500 miles and do it again . Run for a 1000 miles and change it again. The detergents in the oil usually will clean up the engine by then but I run it to 3000 miles and do another change. I found that by this time I am go to go for my usual 5000 mile changes. Also at the 5000 mile change I have seen no visual change in the color of the oil. Mind you this was expensive to do back when I bought my XJS which took 12 quarts but I found the results worked for me. By the way so far I've only used dino oil even in our new cars.

 

Same filter through the whole process?