The fuel injected for DPF cleaning is for the catalytic converter to burn in order to produce heat necessary to burn the carbon in the DPF.

Thanks Graeme, so if it burns in the CAT, it could be delivered to the exhaust manifold (say post turbo) and save a whole world of problems!

That's why I'm suggesting the manufacturers should have come up with a better design for getting the additional fuel to clean the DPF filter core during Active DPF regens.

I'm asking if it could have been designed so that the additional fuel is injected separately. That is via another dedicated injector directly into the exhaust manifold, thereby getting to the CAT and subsequently DPF more directly than the current method of additional fuel being injected into the cylinder on the exhaust stroke. That alternative design would prevent oil dilution from diesel getting past the rings into the sump!

Unless there's a very good reason for not doing that (other than cost to the manufacturer).

Out of interest this afty, I just logged oil pressures in my Volvo XC90 with a 2.0L turbo diesel engine, it runs at nearly 60psi at 70mph (approx 1700 rpm). I know it's a different car entirely, but that's more like what I'd expect to see in just about any car.

Regards,
Jon 1992 RR Classic 3.9 efi Vogue
===================
Both my fatties now gone...
Previous: 2011 L322 4.4 TDV8 Vogue SE /// 2002 L322 4.4 V8 HSE /// 2009 Discovery 3 2.7 TDV6 XS /// 2004 Defender 90 TD5 /// 1993 110 V8 Snatch Landrover /// 2005 Discovery 3 2.7 TDV6 SE (Aus) /// 1990 110 Isuzu 3.9 County (Aus) /// 1976 Series III Trayback (Aus)

OK, just Googled it. Such systems already exist.

Ford for example have a system on their Euro 5 models which has a 5th injector (on 4 cyl cars) or more technically a vaporiser, which injects diesel directly into the exhaust post turbo for the purpose of Active or forced regens.

They suffer from blocking with carbon deposits though it would seem, so they end up not performing a regen...

So there's no perfect solution, although that may be preferable to oil dilution causing engine damage.

Jon 1992 RR Classic 3.9 efi Vogue
===================
Both my fatties now gone...
Previous: 2011 L322 4.4 TDV8 Vogue SE /// 2002 L322 4.4 V8 HSE /// 2009 Discovery 3 2.7 TDV6 XS /// 2004 Defender 90 TD5 /// 1993 110 V8 Snatch Landrover /// 2005 Discovery 3 2.7 TDV6 SE (Aus) /// 1990 110 Isuzu 3.9 County (Aus) /// 1976 Series III Trayback (Aus)

All DPF regeneration fuel is injected during the power stroke, never during the exhaust stroke.
The description in the workshop manual is pretty clear.
The post injections - as they call it - are either straight after the pilot and main injection - at the beginning of the power stroke - or late in the power stroke.

In none of the 6 posts about SDV8 engine failures I've seen evidence the failures were caused by oil dilution.

Even in the amazing post by 4RRS there was no clear evidence.
Yes, the #3 big end bearing shell had spun 10 degrees, covering the oil entry, but was THAT the cause or did it change position due to friction because of thinned out oil?
We will never know I suppose.

Sure, the manual mentions the risk of oil dilution because of the extra injected regeneration fuel.
They continue by saying that as long as the calculation thinks it's below 7% it's all good.
Why are people not posting UOA reports warning about elevated oil dilution before the calculation thinks it's at that level?
There are enough users dumping engine oil after 6000km or less.

Another fun fact: ACEA has dropped the C1 spec, I could not find a reason for it.
The C1 oils are still on the shelf, of course.
C4 oil is now the official low SAPS oil, then you also get high HTHS.
The alternative is C2 / C3 oils with mid SAPS levels, those oils are still recommended (allowed) for diesel engines with DPF's.
To date I have to found what the complete specs of Ford WSS–M2C934B oils are, it would be nice to read what minimum HTHS value Ford wants in the T(S)DV8's. 2012 4.4TDV8
2000 Honda S2000

Thanks SpitfireS, some great points!

I found a very well written article on post injection from all the way back in 2008 here: https://biodieselmagazine.com/articles/und...oblem-2290

The main take-away for me was the following:
"Post-injection of fuel into the cylinders is intended to vaporize in the cylinder but not combust, exiting then through the exhaust valves and traveling downstream where the introduction of the unburned fuel to the catalyst creates an exothermic reaction incinerating the collected soot. Inevitably the heavier fractions of fuel will not vaporize during post-injection and in liquid form can adhere to the cylinder walls. Through the slapping motion of the pistons and oil rings, the unburned fuel from post-injection can make its way through the tight, hot quarters between the piston, rings and cylinder walls. The fuel accumulates in the crankcase and dilutes the oil, which is a major concern regarding engine wear and longevity."

So effectively the fuel is being delivered unburnt to the CAT, where it combusts (that's my take on an exothermic reaction) raising EGT's to crazy levels (even hotter than a McDonald's apple pie) to turn carbon into carbon dioxide and perform a regen of the DPF.

Regarding engine failures, it still seems a mystery why SDV8's have reported issues whilst TDV8's seemingly don't?

Jon 1992 RR Classic 3.9 efi Vogue
===================
Both my fatties now gone...
Previous: 2011 L322 4.4 TDV8 Vogue SE /// 2002 L322 4.4 V8 HSE /// 2009 Discovery 3 2.7 TDV6 XS /// 2004 Defender 90 TD5 /// 1993 110 V8 Snatch Landrover /// 2005 Discovery 3 2.7 TDV6 SE (Aus) /// 1990 110 Isuzu 3.9 County (Aus) /// 1976 Series III Trayback (Aus)

Now this is SHOCKING! From the same article BTW, it says:

"Not all after treatment systems providers utilize post injection in their regeneration strategy. Some incorporate in-stream fuel injection where injectors positioned in the exhaust stream squirt controlled doses of fuel downstream of the combustion process, some coupled with a burner, to create the exothermic reaction needed to incinerate the trapped particulate matter while avoiding the issue of fuel dilution altogether. Caterpillar utilizes this in-stream approach with a diesel burner in the exhaust stream. Currently it's a matter of economics-OEMs see a cost savings in utilizing existing fuel injection systems rather than tacking on the additional cost of extra equipment. A 2007 Society of Automotive Engineers paper written by engineers from Tenneco Inc. and AirFlow Catalyst Systems stated that, "Although most 2007 systems introduce the fuel for diesel particulate filter (DPF) regeneration through in-cylinder post-injection, it is likely that 2010 systems will also need in-stream fuel injection to help avoid oil dilution and potential premature engine wear."

So it frankly beggars belief that LR has continued with a post injection solution on an engine for over a decade, when the problem of oil dilution and premature engine wear (as a consequence of this 'el-cheapo' practice) was being discussed back in 2008!

I guess they don't want to invest any money / R&D into diesel technology as it's being rapidy made obsolete by the legislators... yup, I think my next vehicle may well be an EV. In fact Tesla Model X's are very cheap right now & much less to go wrong!

Top tip - Buy shares in Rolls-Royce and Google up SMR, 'cos the countries going to need them by the bucket load!

J 1992 RR Classic 3.9 efi Vogue
===================
Both my fatties now gone...
Previous: 2011 L322 4.4 TDV8 Vogue SE /// 2002 L322 4.4 V8 HSE /// 2009 Discovery 3 2.7 TDV6 XS /// 2004 Defender 90 TD5 /// 1993 110 V8 Snatch Landrover /// 2005 Discovery 3 2.7 TDV6 SE (Aus) /// 1990 110 Isuzu 3.9 County (Aus) /// 1976 Series III Trayback (Aus)

Regarding TDV8 vs SDV8 failure numbers, I expect that the number of L405/L494 vehicles fitted with the engine is many times the number of L322s fitted with the engine - some 8 years of L405 production and 7 years of L494 versus 2 years of L322.

Way too much speculation......
No real evidence of actual excessive SDV8 engine failure rates. A cluster of cases and some anecdote from a french mechanic does not make a convincing case.
No evidence of a direct link between oil dilution and bearing failure or even oil dilution full stop.
No evidence JLR ignored the issue or failed to implement available technology.
Early DPF cars did have oil dilution issues and this is a fact. I had one that was subject to a software update to fix it. The issue was very evident in rapidly rising oil levels which if not noticed ( via the dipstick) could lead to a destructive engine runaway. JLR have 2 ways of identifying this issue which is software monitoring and a very accurate and sensitive electronic oil level sensor linked to a driver warning. Exhaust injection of fuel was not the only solution to potential oil dilution issues in 2008. The other option (as adopted by JLR and many others) is to put a CAT infront of the DPF ceramic core which creates the required burn temperature of soot with much less fuel.
Any lowering of viscosity by fuel will be offset by the natural increasing in viscosity due to soot loading. Infact I'd be much more inclined to point the finger at excessive soot in the oil as a potential engine fail cause than fuel in the oil. Once oil has reached it's soot holding capacity the soot precipitates out and can form more solid accumulations of 'sludge' which can at worst block oil ways, filters, pickup strainers and at best restrict flow ( increase oil pressure ). Soot loading oil is easy to do with poor driving habits and neglected oil servicing. ?si=JiiMJwSsCUc6lTii 2012 TDV8 Vogue (L322)

I would guess short journeys and cold engines are a big cause of oil dilution, diesel doesn’t evaporate until 50-60 degrees and biodiesel is worse.

Short journeys and cold engines also create excessive soot. 2012 TDV8 Vogue (L322)

I have no skin in this game but I reckon if you trawl the internet you'll find "facts" for every car and engine ever made saying they are unreliable. In much the same way that having had a quick google for medical stuff suggests I am living on borrowed time and have been for the last 10 years because I can fit my ailments into just about any scenario that says I should have died yesterday or at the latest die tomorrow.

On any forum there are a few people that are rightly frustrated by either their vehicles or the manufacturer who wont fix everything under warranty (even for 10 year old cars)

The V8 has been around for years and is probably in thousands of cars but one or two anecdotes around their reliability and suddenly it's a bad buy - I don't think so  Geoff

I don't think anyone was suggesting it's a bad buy.

It's a cracking buy and a great and reliable engine, as stated in my opening post.

I was just trying to understand if there was a definitive theory as to why in a few months there has been 3 reports on this forum alone of catastrophic engine failures.

It would seem there isn't a single identifiable problem, which in itself is very re-assuring. The general consensus then, is that the cars that failed may have had suboptimal service intervals, incorrect oil grade used, frequent short journeys leading to oil dilution and/or soot in the oil, or are just one-off failures, which can happen to any engine from any manufacturer!

It did become apparent during the course of this discussion that nearly all the reported failures were to SDV8's fitted to L405 Range Rovers.

Would that put me off buying an L405? Not at all! But it would make me think twice about anything that hasn't been serviced within an inch of its life, so preferably from a forum member, with a pile of receipts to back up the service history! 1992 RR Classic 3.9 efi Vogue
===================
Both my fatties now gone...
Previous: 2011 L322 4.4 TDV8 Vogue SE /// 2002 L322 4.4 V8 HSE /// 2009 Discovery 3 2.7 TDV6 XS /// 2004 Defender 90 TD5 /// 1993 110 V8 Snatch Landrover /// 2005 Discovery 3 2.7 TDV6 SE (Aus) /// 1990 110 Isuzu 3.9 County (Aus) /// 1976 Series III Trayback (Aus)