Background: There is this car podcast - The Car Doctor - that I listen to [http://www.cardoctorshow.com/]. Ron Ananian, the car doctor, has strong opinions that he voices during the start of the podcast, and then manages to take a few phone calls. Since Click and Clack are no more [https://www.theverge.com/2017/9/30/1...odcast-comedy], I've been listing to the Car Doctor.

Oil change frequency in Direct Injection Engines: During a recent podcast, the Car Doctor relayed info he was taught at a course he was taking to stay abreast of new car technology. In brief, the instructor, who has nothing to gain, stated that direct injection engines should have their oil changed MORE FREQUENTLY than either the manufacturer states of the change engine oil light indicates in order to reduce valve deposits.

Question: Most of us may change oil more frequently by virtue of how we drive our Jags (not when it is raining, for instance). But (1) should the oil be changed at 6 months rather than 1 year (max from manual) or (2) 7500 miles rather than 15,000 (I think that is the max from the manual). I'm in the group that changes the oil approximately yearly. Does anyone have evidence that DI engines require more frequent oil changes than manufacturer recommended, as stated by this instructor in New Jersey?

Best,
WRAIR

 

ooooohhhhhhhhh looordie......
ADMIN! SHUT THIS THREAD DOWN BEFORE IT EXPLODES!!!!!

 

If we are talking about manufacturers OTHER than Jaguar...
Yes, some of the top manufacturers, BMW, Toyota, had to revise their oil change intervals.
Most new designs have eliminated a true direct injected engine.

Jaguar had no problem, due to clever design and they updated the oil specs instead.

The only evidence we have that Jag/LR does NOT require more frequent oil changes than recommended is that none of the small production of cars have suffered the same problems that Toyota had for instance. Audi was a complete nightmare at 40,000miles.

However, there is a fly in the professor's ointment, deposit buildup is not solely due to inadequate oil changes. And more frequent oil changes will do nothing for valve deposits.

 

Cee Jay,

Not sure the origins of your response; as I explained, this came from apparently respected people in the instruction and auto repair business. If ludicrous, please explain.

 

Cee Jay is referring to this and many other threads...
https://www.jaguarforums.com/forum/x...update-167480/

 

Got any links please? (By PM if you'd rather not risk thread hijack.)

 

The Search function is very helpful. There are more posts about oil than dogs have fleas. Google is helpful, too. As for Audi, search that forum.

Give a hungry man a fish and he won't be hungry tonight. Teach him how to fish and he won't be hungry for the rest of his life.

Mick Jagger said it - "You can't always get what you want. But you get what you need."

 

It fits perfectly in this thread because despite the frequent oil change there was near total blockage at 67k. Very kind of him to post pictures.
Audi FSI Engine Carbon Build-up Megathread

30k miles https://www.audiworld.com/forums/q5-...ld-up-2817781/

 

Thanks much JagRag! A very helpful response, indeed.

154 messages in that link, some of them answered my questions!

I​​​​​​ need to improve my search competency. There is training on how to perform effective searches, but it also depends on the search engine.

wrair

 

Sounds like you did the reading, so this is probably not news, but long story short-- yeah, probably good to do 6 mos/5000mile change intervals on these engines. And if you DIY, I'd use 0W-20 rather than 5W-20.

 

Thanks - I'll do some reading.

 

Ohhh. Have read and am not impressed by Audi's engines.

Sorry, off topic really, though I suppose the claimed ways to reduce the carbon deposits apply (if they work) to jags as well.

Thanks for the links.

 

Enough water has passed under the bridge where I feel very confident in Jaguar's ability to dodge that bullet- great job Jaguar.

Yes the ways of reducing carbon deposits are universal. And Jaguar has already taken the most pertinent steps on our behalf by selecting the perfect oil and tune.

Incidentally, was there something mentioned by the Audi/VW community that stood out?

 

Some search tips here, maybe JagV8 was too modest to toot his own horn?

https://www.jaguarforums.com/forum/j...le-site-60209/

 

Some of the horror carbon deposit videos on youtube certainly stood out

(I'm not likely to become a jag DI engine owner - just don't happen to like the current cars - but just about every other make I've considered is also DI. Oh well.)

 

Cheers, Norri.

Sadly I think google maybe took out the "+" feature?

 

More progress?

 

As you are aware, there are tremendous advantages to DI and the inherit misgivings have been mostly addressed. Mazda has a new technology that you might find appealing.

The culprit is not DI rather mechanical valves themselves, which I can assure you will be the very next thing to go from internal combustion engines.

 

Cee Jay! Dude! Had to laugh as soon as I saw your first post! Sooooo True!

Q&C,
As I have discussed in the past, Jaguars 5.0L is not excluded from the carbon buildup issue. It is in fact the regrettable byproduct of direct injection, vs older multi-port injection. Having also come from the Audi side, they were using Direct Injection as early as my 2005. That puts them over a half a decade ahead of Jaguar,and still face the problem today.

In addition, I had my XKR intakes cleaned, with dynos before and after....
Being the new owner of a used car, I cannot say how it was treated its first 5 years, but I gained 30 ft/lb of torque after the cleaning!

FWIW: Audi also refused to acknowledge carbon the problem, claiming it was the owners, and perhaps the US grade fuels we use over here (forcing Audi owners to be sure they use top tier fuels). Far too many owners proved they followed Audi spec oils and fuel requirements and still encountered the problem. The Audi 4.2 V8 was a powerhouse and had all its owners in an uproar as it output declined........... Even my little 2.0 turbo A4 had the problem.

Its not the valves to blame, but probably more related to the increased valve overlap allowed by the leaner mixture. The intakes are subjected to the same carbon that use to only pass the exhaust side of the chamber.

WRAIR, as Cee Jay points out, oil is almost a taboo topic here, but I will pass on one thing I do. The 5.0 has a top mounted filter. I trade it out every 2500 miles, and cling to a 5k oil change. Gotta love that top mount filter, regardless of change intervals...

Vince

 

I thought the (DI) intake valves don't have petrol washing them clean and that is what allows the deposit build up.

Byproducts of combustion / traces of oil / etc going back into the intake (PCV or whatever) can't help no matter which oil or how recently changed.

Fitting an oil catch can / PCV bypass or the like seems a plausible way to reduce it.

I don't see how to avoid/reduce any carbon (& oil/etc) that swirls out of the combustion chamber past the intake valve (short of changing the way the car works).

I've read advice/suggestions to run a DI engine at higher revs (not all the time!) but I fail to see how that would help. It's not going to burn the carbon off the rear of an intake valve as far as I can see. Might bake it on, though.