@Gremlin500

Not measuring the ash in the DPF, but I am measuring how often the regens occur on the basis that if the DPF was filling up more quickly due to higher ash content in the oil it would be demanding more frequent regens. That is my (possibly flawed) logic.

As a reference mine is regening every 80miles on a steady 65mph m-way cruise but can exttend to 150 miles if it involves long slower 50mph road work sections and non m-way driving. 2012 TDV8 Vogue (L322)

Mine regens every 150 to 170 miles. I never get to the 200 to 300 that others seem to achieve. I've thought about the diy cleaning kits or even having the DPF cleaned professionally but would it make much difference?
Presumably, if it's removed by cutting it out and replacing with the special clamps, it would be easy to remove for cleaning or replacing in future.🤔

What's your car's mileage? 2012 TDV8 Vogue (L322)

@Alex, I’m sure it only triggers on soot (which can be burnt off) and not on ash, which remains in there forever, hence the need for “Ultra-Low” SAPS oil, the only way to remove the ash is by physical means (flushing) as far as I understand it. There is discussion about some “treatments” harming the DPF, so proceed with caution.
I would seriously reconsider your current mid-SAPS regime, if I were you.

JLR say:

“ Unauthorized use of the aftermarket fluids produces a significant risk to soot
burn rates and DPF peak temperatures real world driving conditions. These fluids are not authorised for JLR use.” “If it ain’t broke, don’t fix it” -where’s the fun in that?

What JLR are reffering to are fuel addatives for DPF 'treatment' and not oils. 2012 TDV8 Vogue (L322)

could be interested

@JayGee, I think you misunderstood my post, Alex was talking about DPF cleaning above, to mitigate using the “wrong” oil, and I was advising caution in regard to that aspect. “If it ain’t broke, don’t fix it” -where’s the fun in that?

@Gremlin I am working on the assumption that the monitoring of the dpf is purely on pressure differential and can not distinguish between soot and ash causing the DPF needing to regen.

I accept that over time the increased ash content in C3 may cause the DPF to become full and need cleaning/replacement earlier but if that means this is at, for example 150k miles rather than 200k miles if using C1, then perhaps that is a trade off for not having to replace the engine at 100k miles due to a failed crank. DPFs are cheaper than engines.

The short answer is I don’t know for certain if 5W40 will prevent the crank failing or if it will block the DPF quickly, but happy to report on what does/doesn’t happen for the benefit of others here who may be considering a swap to 5W40 oil.

JayGee wrote:

What's your car's mileage?

@Alex,

Reading back through the thread, the sulphated ash content increase from C1 to C3 is +60% difference, so you can expect a significant additional build-up of ash when switching to C3, however this is not a short-term effect, as you say.

Pressure differential will increase much more significantly from short-term soot build-up between regens, therefore gives no true indication of ash build up whatsoever, -that happens over a much longer period of time, and almost invisibly.

Given JLR say physical/chemical flushing can damage the DPF and result in reduced capacity to regen, has anyone investigated the cost of a new DPF from JLR, should this eventuality happen?

Personally, if I was a DPF, I would not choose to voluntarily reduce my life by 60%  “If it ain’t broke, don’t fix it” -where’s the fun in that?

The ACEA specification is that all C grade oils - C1, C2, C3 and C4 are rated as ‘Low SAPS’ and suitable for DPF equipped vehicles. Yes C3 has a 60% increase in SAPS over a C1, but it is still at a low level.

One question I have not been able to find an answer to is - what is the life expectancy of a DPF when using C1 grade oil? On the basis that C1 oil still deposits ash into the dpf, it will eventually be ‘full’ and require replacement or cleaning.

For arguments sake what if the expected life span is say 400,000 miles. And assuming the use of C3 oil will directly reduce the lifespan of the dpf by the same proportion of the increase in SAPS - 60%. So I would need to clean/replace the DPF at 160,000 miles.

I think the use of C3 oil that is still classified as low SAPS and suitable for DPFs means it is highly unlikely that the 60% reduction in DPF lifespan is likely to be correct, but possibly a very worst case scenario.

A new DPF is £930 from Autodoc. So say it is £1,500 fitted. I am still working on the basis that if at 160,000 miles I am spending that on a new dpf, but my engine is in good order and no snapped crank, I am happy.

Not trying to argue with you Gremlin, just sharing my thinking and welcome your thoughts on my approach. Maybe we need to revisit the idea of sourcing some 5W40 C1 as the ideal solution?

@Alex:

Yes this is just healthy discussion, no argument of course.
I think to avoid confusion here, we have to clearly differentiate between early DPF architecture (C2/C3 MID-SAPS) and later DEF-DPF architecture, which absolutely requires C1/C4 LOW-SAPS oils, this is what you have misunderstood I think, because you incorrectly referred to C3 as “low” SAPS, which it isn’t. Read carefully the scholarly article I posted above, it gives an excellent explanation of the progression of the technology, and the various substrates and coatings employed. This is complex chemistry certainly, and there were without doubt very good reasons for the requirement for reducing the sulphated ash content even further in the later DEF-DPF vehicles.
Would you accept a 60% reduction in salary as insignificant?  “If it ain’t broke, don’t fix it” -where’s the fun in that?

Having read this thread I must say it’s a great discussion. Like many others I am very interested in the long term effects of different oil and grades. Look forward to see how it goes with different theory’s. I have a 2018 sdv8 euro 6 (with adblue) and for what’s it’s worth, I think moving to a 5/40 oil is a good thing. In my humble opinion after Doing a little reading I agree a euro 6 engine would require low saps (C1 or C4) oil. I have watched LR time with interest on the oil topic and trust he has done a lot of research, but his engines are not euro 6 and therefore guess his research lead him to conclude that a mid saps / DPF (C3) 5/40 is best for his requirements.

Last edited by M11buc on 17th Nov 2024 4:40am. Edited 1 time in total

Deleted. Geoff