I’ve just found this on the Jaguar F-Pace forum which may assist in understanding the issue. Not sure if this has been posted before, apologies if it has.
It was posted in response to a Jag owner who’d previously had a RR Sport where the crankshaft failed at 22k.

Short trips and cold starts have been contributing to the death of your engine. These had a design flaw. As they sold far more then they ever estimated, they forgot to replace the moulds in time. So the 'nodge' on the cast block where the 'hole' in the semi circle section of the crank bearings slotted in, faded in the last thousands of engines. Then there was a problem with the thickness of these bearings. Car manufacturers use contractors to supply parts. So did Ford [ the engine originated from Ford ]. So there were tolerances in the thickness. But they mixed these batches. So it could happen that opposing halves of one bearing varied op to 0.2 mm in thickness, effectively bending the carnkshaft every half turn slightly. Also there was a mistake in the tooling ; a CNC bench that removed edges near the flanks of the excentric parts, undercut slightly forming a snapping point like you cut a scratch in a panel of glass. Evidently 90% of snapped krankshafts fit with others in detail. A man in South Africa spend loads of time investigating this [ https://www.4x4community.co.za/forum/sh ... k-Failures ].

The result of some aspects put together [ for this engine ] is that at cold starts, this semi section gets a 'shove' when started since the crankshafts is resting metal-to- metal, worse if the car is used rarely, let say once every 5 days or less. Then, some people have the bad habbit of pushing the throttle at starting and revving up : not good at all. Sadly Jaguar made this the automatic starting procedure for all F-Type engines, why....

Then, driving a short distance leaves the oil cold and it does not lubricate well, also water from condensation does not evaporate and builds up in the sump. Some people only observe the 'milage' for sevice intervals, though one year is the minimum on the TdV6.

Eventually such a 'shove' could be enough for a section of the bearing to shift over the 'nodge' and ends up wedged between the other bearing section and the crankshaft, extremely deforming the crankshaft every turn and in a few turns it snaps off..

Sadly JLR did not pro-actively pick up this problem. Sofar around 8% of all TdV6 ended this way. Sometimes at very low milage, sometimes at very high milages. The latter with engines well used and cared for, but the 'thin' section from a pair [from different producers] of crankshafts bearing shells was then worn out to a level it would vibrate in the bedding as it rocked when the load shifted from the thicker half to the thinner, so 'shimmied' the section to jump from the nodge that itself was in perfect order.

In Taiwan the authorities has decided that JLR has to replace all engines that end due to a failing crankshaft, no matter age or milage... 2019 L405 SDV8 Autobiography
2023 Defender P400e HSE X-dynamic - gone
2020 Defender P300 SE - gone

2019 Jaguar F-Pace SVR - gone
2013 SDV8 Autobiography - gone
2011 L322 TDV8 Vogue SE - gone
2006 L322 3.6 Vogue Se - gone
1999 P38 4.0 se - gone
199? Classic 3.5 - gone

excellent update
Would you mind posting the link as it is not working, please?
 l=Oo\________/oO=l l:OolΞΞΞΞΞΞΞloO:l

Current
RANGE ROVER Vogue 4.4L SDV8 - 2013 - Indus Silver, on Almond.
RANGE ROVER Vogue 4.4L V8 - 2002 - ex-2003 G4 Challenge Event Vehicle, Stage 3: Australia
RANGE ROVER HSE 4.4L V8 - 2004 - one-of-one Overfinch
RANGE ROVER P38a 4.0L V8 - 1999 - ex-2000 TReK Event Vehicle: South Africa

Previous:
RANGE ROVER Vogue 4.4L TDV8 - 2012 - RANGE ROVER 3.6L TDV8 x3 - RANGE ROVER Td6 x1 - RANGE ROVER Classic 3.5L V8 x1

I didn’t attach a link in my original post......but try this. The relevant section is near the bottom of page 1

https://www.fpaceforums.co.uk/viewtopic.php?f=7&t=5046

I’m a registered user on the site so it might not work for unregistered users but worth a try. 2019 L405 SDV8 Autobiography
2023 Defender P400e HSE X-dynamic - gone
2020 Defender P300 SE - gone

2019 Jaguar F-Pace SVR - gone
2013 SDV8 Autobiography - gone
2011 L322 TDV8 Vogue SE - gone
2006 L322 3.6 Vogue Se - gone
1999 P38 4.0 se - gone
199? Classic 3.5 - gone

Thanks Buz, but I meant the one in you latest post:
https://www.4x4community.co.za/forum/sh ... k-Failures ].

As you can see it's not copied properly

cheers l=Oo\________/oO=l l:OolΞΞΞΞΞΞΞloO:l

Current
RANGE ROVER Vogue 4.4L SDV8 - 2013 - Indus Silver, on Almond.
RANGE ROVER Vogue 4.4L V8 - 2002 - ex-2003 G4 Challenge Event Vehicle, Stage 3: Australia
RANGE ROVER HSE 4.4L V8 - 2004 - one-of-one Overfinch
RANGE ROVER P38a 4.0L V8 - 1999 - ex-2000 TReK Event Vehicle: South Africa

Previous:
RANGE ROVER Vogue 4.4L TDV8 - 2012 - RANGE ROVER 3.6L TDV8 x3 - RANGE ROVER Td6 x1 - RANGE ROVER Classic 3.5L V8 x1

Oops, didn’t spot that URL.

Try this....

https://www.4x4community.co.za/forum/showt...k-Failures 2019 L405 SDV8 Autobiography
2023 Defender P400e HSE X-dynamic - gone
2020 Defender P300 SE - gone

2019 Jaguar F-Pace SVR - gone
2013 SDV8 Autobiography - gone
2011 L322 TDV8 Vogue SE - gone
2006 L322 3.6 Vogue Se - gone
1999 P38 4.0 se - gone
199? Classic 3.5 - gone

Buz1500 wrote:

So the 'nodge' on the cast block where the 'hole' in the semi circle section of the crank bearings slotted in, faded in the last thousands of engines. Then there was a problem with the thickness of these bearings.

If that were true, then the early 3.0 engines in the RRS/D4 would be fine.

But, they are not, they still snap cranks...

However, I do agree with short journeys not doing the car any favours

Hi Mike,

The text contained in my post was merely copied from another forum. It appeared to be based on some very detailed investigation and written by someone with a good understanding of the issue. 2019 L405 SDV8 Autobiography
2023 Defender P400e HSE X-dynamic - gone
2020 Defender P300 SE - gone

2019 Jaguar F-Pace SVR - gone
2013 SDV8 Autobiography - gone
2011 L322 TDV8 Vogue SE - gone
2006 L322 3.6 Vogue Se - gone
1999 P38 4.0 se - gone
199? Classic 3.5 - gone

I think it's a combination of issues, TBH

Buz1500 wrote:

Hi Mike,

The text contained in my post was merely copied from another forum. It appeared to be based on some very detailed investigation and written by someone with a good understanding of the issue.

pld118 wrote:

L405 3.0TDv6 crankshaft poll now added to this thread (below)... relevant to the original thread title which covered 'rumours and facts'.

[ffruk forum members] have polled no issues thereon with their L405 3.0 TDv6 crankshaft; and

So far, no L405 3.0 TDv6 forum member owners have voted to report their crankshaft having failed and/ or that warranty/ LR left them high and dry in that eventuality.



https://www.fullfatrr.com/forum/topic54027.html

An interesting thread found and posted today by Buz. The thread suggests preventative maintenance options. It does not cite any examples of L405 3.0 TDv6 crankshaft failure which is the point of this ffruk thread and the drum long term banged on this forum. Also worthy of note that the last entry on the thread highlighted by Buz was in 2016 and we are now in 2020

Based on sound research, well documented on this and linked threads, there is still nothing to worry about with the L405 TDv6, unless or until someone produces a shed load of stats of L405 owners being left high and dry following crankshaft failures... And if that was a fact, given the reach of this ffruk forum, would we not have heard by now?

Hi all.

Ive just joined this site. Ive wanted a Range Rover for a long time but circumstances didn't permit.
However now, I am researching.

It seems that immediately previous post was written in 2020. I'm writing this one in Dec 2024.

Couple of points. My mechanic whom I've known for years is determined that I don't buy any JLR engined cars. He has had to replace over a dozen engines in the past year, mostly tdv6, mostly range rover but some XJs too.
All have had snapped crankshaft.

Im not deterred, yet.
Ive been told and I have read that the difference between transverse and longitudinal engine placement means that the DPF regen is less hot on the RR and also on XJ from euro6 (2016) because the layout was changed in jag.

I need to know whether the crankshaft in a SV6 is stronger than a standard one. My mechanic won't encourage me hence my research here.

The reason for the snapped crankshaft isn't poor servicing. It's mostly caused by oil dilution when extra diesel is forced into the cylinders during an active DPF regeneration.

If that active regeneration isn't completed before it's aborted, the extra fuel runs into the sump diluting the oil.
If the quantity of derv exceeds 6% of sump oil, it can cause a crankshaft bearing to spin in any one of several ways. Slipping under the other half; all slipping such that the oil channel is blocked; snapping the crankshaft simply because the oil can't lubricate.

Oil changes within every 5k miles seems to be a solution.
It's important to know the service history before buying because cars driven in the urban environment, clog up the DPF rather quickly and active regen can be triggered but not completed. And again and again until it is completed. Those repeats put fuel into the sump which is why some have seized or spun a bearing or caused engine knocking with as little as 30k miles on the clock.

So; does anyone know whether there's an alternative crankshaft that could be installed, which is stronger?

Higher inertia in RR over XJs is given as another potential reason for RR suffering snapped shafts more than Jaguar. Worth also mentioning that there's an ongoing class action against JLR for this specific issue of broken engines. I suspect that should be enough to fulfill the previous poster's requirement for loads of stats.

Hoping I find stronger crankshaft so that, when combined with more frequent oil changes, I'll own a reliable-engined beauty.

Bazz

Replace both the main and big-end bearings with heavier duty versions (eg Kings) for starters.

Ford redesigned the crankshaft when they used this engine in their F150 truck, presumably because of the failures that had been seen in JLR vehicles. I am not sure if the cranks are interchangeable between the JLR TDV6 and the Ford Powerstroke unit. The engines are effectively the same in many of the main points so it is feasible that they are able to be swapped and a good place to start in researching a solution.

The improved crankshaft was reportedly fitted to the LR engines too. Both the F150 engines and the LR/Jag engines were built in the same factory side by side. The F150 blocks were modified at least with some oilways enlarged that weren't replicated in the LR/Jag blocks. The slippers were tabbed on both engines but tabs are only to ensure that the slippers are installed correctly as tabs won't stop a grabbed slipper from turning. Kings bearings (same part number for LR/Jag and F150) don't have tabs even for these later engines.

So do we know if there is a date or engine number that these improvements were incorporated and if since doing so crankshaft failures have stopped, or significantly reduced?

It would also be interesting to know if any of the engine rebuilders incorporate these improvements into their engines?