Hi Guys,

My S-Type is the first diesel I have had, and it comes with a DPF. After hearing a lot of warnings from people, and finding my engine oil level rising once I thought I would research DPF's and see what exactly I am up against with it.

Please correct me if I am wrong in any respect as I am looking to understand what is involved with having a DPF, so I can do what I can to keep my S-Type and engine as I got them :-)

After a few days of reading up about the different types of DPF and implementations am I right in saying that the DPF collects the soot and other particulates and it slowly builds up in the filter itself. Driving at speeds of 60mph or so for at least 20 minutes, with no drop in speed builds up the temperature in the DPF to 500 degrees or so and burns off the particulates in the filter, turning them to ash with then ejects with the exhaust fumes.

If I do short hops the temperature of the DPF doesnt reach the required temperature and the soot etc just builds up in the filter without being burnt off.

If the DPF gets to 70% capacity the ECU will inject additional fuel into the exhaust part of the cycle passing the fuel to the DPF to encourage a temperature rise to the required 500 degrees. If you do not then drive for 20 mins or so at speed the cycle will abort, and the unburnt fuel has no where to go so it is dumped into the oil sump leading to the oil level rise.

If the ECU does not manage to clear the filter and it gets beyond 70% an warning light will light on the dash and you need to then urgently take the car on a 20 minute 60mph or so steady drive until the light goes out - which it does when it has cleared the DPF through.

In addition to all this the ECU monitors the fuel dumps in the oil sump and moves your service date forward if the engine oil falls to 7% of the volume as diesel fuel.

If the warning light comes up, don't panic, but do make sure you urgently get to do a long fast drive with her - and keep an eye on the oil level.

You need to keep an eye on the oil level as you dont want its lubrication properties watered down, and as you are never warned when the car is trying to clear the DPF this is the only way you are going to know if a DPF Purge has failed.. by monitoring your oil level.

If Jaguar had installed a light to warn you when the ECU had initiated a purge you would know to take her for a higher speed run, but instead you have to watch the oil level watching for a purge that has been aborted instead :-(

Please correct me if I am wrong in any of this - meanwhile I now need to start reading up on the other thing everyone warns me about - the EGR valve.

Both diesel and petrol engines have their foibles and if rather then just be worried, I can understand them they aren't a problem :-) Well, that's my logic

 

I didn't see where you mentioned what to do when the planned DPF regen has failed / too much (NOTE) diesel in engine oil i.e. not to drive the car as you're liable to write the engine off.

NOTE I'd say any. Diesel is a terrible lubricant so severe engine damage is a big risk as is terminal damage. Quite a number of descriptions of written-off engines are on the site and even more on the net.

Also - only some of the cars can do the kinds of checking mentioned and it's not clear how to know whether any specific car can do it or not.

 

Yes, I concentrated on normal use - interestingly when I had the regen failure and the oil level increase the service requester came up suggesting that the ECU does monitor the contamination of the oil somehow - but could have just been coincidence.

Prior to this car I had no knowledge of DPF at all - now I am starting to know far more than I could have ever invisaged ugh.. Prior to my S-Type I always viewed Diesels as hard working solid engines - they still are, but this DPF is keeping me constantly on the edge of my seat checking oil levels and journey lengths until I get the hang of it and am a bit more comfortable with it.

But moving forward I wanted to figure what I could, and air what I think I know, to check I am right as that is half the battle :-)

I am quite lucky in that I use the C1 for the school run currently, and the S-Type is the weekend car with weekly foodshop journeys of about 10 miles or so each way generally at 40mph-70mph and longer family road trip type journeys maybe once a month

When I got my S-Type I brought in in central London (near the Ace Cafe no less :-)) and suspect that it had been doing mainly low speed or short runs as a full tank gave a range of just over 300 miles.. further to a long motorway and A-road run from Crawley to Camberly then Luton and back a fillup now says 450 miles so suspect I have finally given it the run it needed to clear everything through for the moment.

 

I also read that DPF plugged/failure on some cars might lead to run-away diesel. Not sure if this is the case with S-type.

Here is recent discussion:

https://www.jaguarforums.com/forum/x...ed-dpf-183692/

 

It has been known that if people do not monitor the oil level and it gets too high it can start burning off the oil/diesel from the sump leading to engine writeoff.

Something else to be aware of unfortunately.. *but* if you monitor the oil level, ensure you do longer journeys not short, and are aware of how the DPF works you are in with a good chance of keeping everything intact and running well.. well, after all my reading that seems to be the short version of things.. and if the DPF warning comes up take immediate heed and take her for a good run, and if you do see oil rise you need an oil and filter changed.

In exchange you get a diesel Jaguar that really does not sound like a diesel in the cabin when moving, an engine that just pulls and pulls smoothly from 1500rpm, space for my growing family, and good fuel economy for a 1700kg luxury car :-)

I have to admit I found the X-Type AWD a great car, loved the design but found it too small for my family, the X308s will always have a massive spot in my heart - love them to bits, but the S-Type is a car that grows on you lol.. and where it wasnt love at first sight I now trust this car and its capabilities and am starting to enjoy it's marmite shape.. hence it's become important to me, whilst I am not technical or that good at repairs (yep fix one thing and break something else in the process usually lol) it's important that I understand it to be able to look after it..

 

Gosh Steve . . . such a brave chap you are. Like you, but for years now, we opted to learn (read "monitor & maintain") our MY07 S-Type 2.7L V6 TTD. For fuel reasons, Australia never saw these engines until after the MY06 update. Thus, they are not numerous and ours creates plenty of interest. Our country location and wide open rural highways make any drive a spirited but effortless experience. I lament your full tank range figures and remember a contemporary 2006 British single tank road test from John O'Groats to Lands End at highway speeds of up to 70mph wherever possible.

Our range prediction reads towards 1100Km and generally delivers. Neither oil dilution nor DPF regen have ever been an issue for us . . . NEVER . . . but then, I turn left at the end of our street, and immediately at 100+Kph with closest town 60+Km away . . . and our capital (Sydney) a leisurely 600+Km away.

But, as any fair reading of your posts suggests and I can verify . . .

• this is NOT a car for everyone; if you are a city driver, forget it; this is a touring car for wide open spaces traveled quickly, quietly and effortlessly;
• this is NOT a car for drivers who aren't sure what a dipstick is, and who limit their Jaguar experience to filling up with fuel . . . and let's be honest, that includes many who post briefly here with their "lack of maintenance" issues, then disappear;
• this is DEFINITELY a car inspired to evoke all sorts of "we'll all be ruined" opinions . . . generally from those who have never owned and maintained one, but who can quote a litany of disasters in the hands of those whose circumstances and/or ignorance would have been better served, IMHO, by a petrol version.

Yes, Steve . . . brave indeed. Of our 6 running Jaguars, XJ-S will sulk in garage while daughter grabs the 4.2L XK8 . . . but already out and purring, our TTD S-Type is first choice for me . . . this diesel variant being voted Car of the Decade by Australia's premier motor mag. Coupled to a superb ZF 6spd shared with the XK8, the V6 TTD may not have the bark of a big V8, but it has plenty of bite for such a well balanced package. However, I have learned to crow quietly.

Cheers,

Ken

 

As you are in Britain go to Halfords, they have a dfg cleaning facilities which cost £80. I have heard on another forum that it is very good.

 

Seriously? Did I miss something? I read Steve's posts as already knowing the issues and knowing that all the car needs is a regular opportunity to stretch its long legs. Perhaps spend a fraction of that GBP80 (sorry, my k/b doesn't do pounds, euros etc) on fuel to get out of the city for a weekend drive.

 

Some people have found that if you get them cleaned that they work a lot better. It's like getting your chimney swept the fine particles are normally burnt away but there has to be some sort of residue.

 

Thanks for the feedback everyone I appreciate it.

When I was first informed of the potential doom with the diesel powered S-Type, first thing I did was panic to be honest as I have always thought of diesels as solid workhorses, rubust and not prone to failure, and here I was with a new (for me) Diesel S-Type reading all this - and to add to it I did have an aborted regen and the obligatory oil level rise just after getting it.

But after sorting the oil issue, noting the service required warning had moved forward, and doing a medium length run I sat down and started reading.

Now I know much more (I will still never be a mechanic or anything but challenged with car repairs lol) I have taken her for the long steady run at speed - around 200miles or so for the round trip, seen the anticipated mileage per tank suddenly shoot up and currently the oil level is stable and I am happier - wary still but happier :-)

The forums are full of threads about engines self destructing, DPF filters getting blocked and needing garage facilities and maybe a replacement DPF at £1000, oil levels getting to the level of the pistons and then feeding the engine until it self destructs - but these are all extremes, and yes they have happened but I wanted a thread people can find that covers it from a diesel newbies perspective and shows yes there are things you need to do (much the same as there are specifics to keep an eye on with Petrol engines) but as long as you do long runs frequently, don't treat it as a school run car (yep NOW I am glad my wife persuaded me to get a C1 for the school run) and just monitor it - fuel economy, oil level, when it last had a long run I believe you wont have any issues outside of the usual breakdown of parts etc.

I went for the diesel version as it had the best reviews and fuel economy, only finding its foibles after purchase - initially scary but once you have read up on DPFs in general and then taken the warnings in context of what you now know - it's just another thing to keep an eye on :-)

As I mentioned we had an X308 initially - really loved it from day one, moved onto an X-Type AWD which whilst incredible proved too small for our family with two teenage kids, back to another X308 - again I loved that car, but it had to go, then onto the S-Type.

The S-Type was an odd choice for me as it was based on practicality rather than looks.. we needed more space, X358s were just out of budget, and a diesel's fuel economy made sense.

The fact that my S-Type has a leaper helped seal the deal (yep I am that vain lol), and as time has gone by it has really, really grown on me.

The cabin is quiet, the engine as smooth as they come, the motorway ride superb and it cruises effortlessly at whatever speed you want. It pulls like nothing - smoother than a petrol because of its power range, and the shape - initially not keen on it, but now love it and it is even my first Jaguar with a boot that opens wide via remote for loading the foodshop etc. (that sold it to my wife :-))

The X-Type was a fun car, the X308s gorgeous classics and you knew that from the first time you sat in them, but the S-Type is one of those cars that just grows on you and in doing so does genuinely surprise you.

Every Jaguar has bitten the dust as I have gone, much the same as any other manufacturers car.. and I am not daft I know the S-Type will do too eventually BUT at the same time it's important for new owners to know that the Twin Turbo Diesel S-Type is a great car, and if you heed the warnings but just keep an eye on things you will be OK - it is not all doom and gloom - and this is from someone addicted to V8 petrol Jaguars lol

 

Steve . . . Steve . . . tone it down mate. You've sold it to yer wife; that's great; but Jaguar are not making any more of them (later F-Types don't count) so why fuel (hehe) further competition for the few that live.

On a more serious note, following liaison with Jaguar, we should emphasize 2 important aspects referred to in detail among other threads here over recent years . . .

• the pre 2006 TTD 2.7L S-Types may, or may not, have DPFs that are central to this discussion;
• all 2006-2008 TTD 2.7L S-Types have DPFs, although some may have undergone after market surgery, with or without re-mapping . . . this engine contained so many updates to the injectors, VVT, EGR, and mapping that it is vastly different to earlier TTDs;
• almost all MY08 S-Types, including the TTDs of which a few received 3.0L engines destined for the coming F-Type, were in fact assembled in 2007 and stockpiled . . . proof seen from the outset of 2008, the S-Type's former assembly line at Castle Bromwich was in full production of the F-Type which was being delivered to dealers in February for March 1 2008 release.

Best wishes Steve and thanks for your productive thread,

Ken

 

While I do understand the bearing issue due to oil dilution, I'm afraid I don't quite follow the runaway engine theory due to regen failure. It's not quite as simple as an overfull sump that initiates the event. How does the oil/fuel mix get into the combustion chambers?

 

I dont know exactly - it is just something I have heard mentioned in amongst the other possible issues... :-) Blah..

Thankfully just keeping an eye on the oil level, and doing long runs is enough to avoid most, if not all of the issues, plus knowing what to do should anything crop up - as always prevention is better than cure :-)

 

Via the turbo(s)?

Via PCV (if diesel has it)?

 

Hello Mikey . . . you pose a great question but I suspect accurate and impartial answers will be few and far between. Yes, any oil dilution, but especially with diesel fuel, will "wash" any bearing surfaces (including valve stems, cams, buckets as well as actual bearing shells) and I firmly believe this may be the source of the few examples I have seen of ruined engines, even broken cranks, reported either here or within the UK forums.

As to runaway self ingestion, I suggest that fuel diluted oil akin to "bore wash" may see some blow by past piston rings, but I would have thought that compression (16-17 : 1) would force any such fuel/oil to be directed down into sump, not up into combustion area. For that reason, I suspect that the pathway is via the EGR . . . fuel diluted oil fumes fed into the intake manifold upstream of the throttle body and thus beyond the driver's control. Injectors won't do it, and I know of no other pathway for fuel enriched sump oil to reach the combustion area.

Alas, the big problem with blaming an EGR pathway lies in well documented examples of runaway diesel destruction that I have examined . . . well written, detailed, but almost all were stationary plants on oil rigs and other industrial installations for which EGR was neither mandated nor mentioned. No; close examination points to lubricant failure, but not self ingestion.

So, on balance, I see that self destruction is inevitable if fuel dilution of oil lubricant raises friction in bearing surfaces to the point of overheating, burning and failure that will lead to catastrophic destruction . . . but self ingested runaway detonation destruction? The spectre of a faster and faster engine spinning uncontrollably off the dial, despite turning off the ignition, is quite frightening, but is it real? If so, how? Maybe via EGR if so fitted. But otherwise?

Years on, and with regular monitoring, self servicing and surrounded by high speed highways (100-110Kph, good grief Charlie Brown) it just aint an issue for me. I am sure that Steve's vigilance is also well placed. For the occasional pic of a dead engine and countless "someone told me" stories, I am yet to learn first hand from someone just like me. LOL.

Cheers,

Ken

 

EGR feeds back exhaust gas - you're seriously saying that sump oil containing diesel can get into that without burning and in sufficient amounts to cause runaway? I don't see it remotely possible or have I misunderstood EGR?

As the diesel in the sump is supposed to have got there by failing to burn when injected late in a cylinder's cycle this seems ever more implausible.

 

This was the thread I saw it on.. I cannot judge if true or not.. but this was what I read aisde from all the other threads I pored through reading up..

Serious Warning V6 2.7 tdvi [Archive] - JaguarForum.com - The World's # 1 Jaguar Car Forum

 

Excellent link. Please read Jag's answer

Serious Warning V6 2.7 tdvi - Page 3

so we're back to square one with not understanding how a runaway engine can occur in connection with a failed DPF regen cycle.

 

Jag's answer does not appear to explain the fuel path for runaway (which has been reported more than once).

I don't see how it can be via EGR but if someone can explain how it can be, please do.

That leaves turbo(s) and (if fitted to diesels as with petrols) PCV.

Anything else?

 

I can't say that I've read of any confirmed runaways caused by a DPF regen cycle. The one last week in the XF section was blamed on DPF but that was the OP's assumption.

The other recent event also in the XF section made no mention of DPF regen.