IRBails wrote:

Oldandconfused wrote:

IRBails wrote:

Wilf still a mystery to me, are you saying regens are based on oil dilution, which still would require some sort of test ? I meanhow does the vehicle know the oil is diluted with out some sort of internal test ?

Part of the re-gen process is to introduce excess fuel so that some unburnt fuel enters the filter to create heat in the filter to burn off the ash. It's the process of intoducing the excess unburnt fuel which allows it to enter the oil, thus diluting it. More short trips=more diesel particulate build up in the filter=more frequent re-gens=more diesel in the oil (=premature engine wear?).

The DPF filter is in the exhaust so I can't see how the regen process adds fuel to the oil? So I am still confused, I think the service intervals are most likely a software algorithm , Land Rover seems to be pretty average when it comes to software, but would love to believe it is active monitoring which would really be the best for engine life .

As above.


To burn off the accumulated soot in the DPF, the DPF has to be very hot. If the engine isn't running hard enough for the exhaust gasses to be above the required temperature, it is heated by injecting fuel on the exhaust stroke, which then burns in the exhaust gas stream and therefore heats the DPF.

The original idea was that driving the engine under reasonable load (i.e. high speeds) would raise the EGT (Exhaust gas temperature) high enough to do that, (passive regeneration) but many people don't load their engines enough (i.e. urban use) to make that happen, hence the artificial "forced regeneration" process. Diesel EGT is directly related to engine load.


As said above, some of that extra fuel gets past the piston rings and into the sump, and dilutes the lubricating oil. The algorithm calculates the level of dilution (badly so it seems). The ECU then asks for additional oil changes between the normal service intervals to stave off the inevitable engine failure that would otherwise result.


This is a big BIG problem for JLR, and they are keeping very schtum about it, hoping that free oil changes will get the engines past the warranty period, after which they will wash their hands of them.

Moral of the story - I would never buy a s/h diesel powered RR or LR. In fact I got rid of my in-warranty car, well before that warranty expired. MY2016 HSE D SDV6 - gone due to fuel dilution problems.

By the age of 50 you have the face you deserve - George Orwell.

Last edited by wilf on Wed Sep 05 2018 11:40am. Edited 1 time in total

There are also other explanations coming out.

Not sure if this applies to the RRS, but there is now an admission of a design issue on the Discovety Sport where the SCRF/DPF has been placed too far away from the exhaust manifold for it to be able to reach the necessary temperature resulting in more active regenerations and very few passive regenerations. It is reported that, in an attempt to help the issue, 2019 models will have heat retention lagging applied to the system. A clear case of sticking plasters onto open wounds rather.

Pages upon pages about all of this on the DS Forum

It’s also worth remembering that oil dilution affects other manufacturers Euro6 models as well, just not to the extent as LR!

Did a bit of investigation on my car today I went out and data logged the injector timing, rpm and boost, I seems that the engineers at land rover have retarded the injector timing so it injects after TDC at 1000-2000 rpm at most boost pressures. I also have a copy of the ecu data and there are approx 20+ injector timing maps ( with out pre and post injection maps ) and most are retarded. I guess this is there attempt at passive regeneration of the DPF and the cause of allot of the problems with oil dilution.

I guess that was their "workaround " to keep EGT up at low engine rpms? MY2016 HSE D SDV6 - gone due to fuel dilution problems.

By the age of 50 you have the face you deserve - George Orwell.

The egt's did not seem that high in the region of 300-400, on cruise, the only time I got decent egt's was at about 3000 rpm with 1.8 bar of boost when it hit 600.

My service message has popped up for the 3rd time in 22k miles and 20 months of ownership. Last time, the oil was changed under warranty rather than using the service. Between the last 'service' and now, I have done nearly 3k miles on European motorways.

Oh and last time, my adblu warning came on the day after the oil had been changed. As it wasn't a real service they didn't check the level.......

Just checked the next service menu and the mileage has dropped 500 miles, I have only done 180 miles since the oil change

[quote="IRBails"]

Coedlan wrote:

Is the safeguard against this weakness intermediate oil changes then?
I would rather do my own intermediate oil change than trust the “algorithm”

Dave Harries wrote:

The egt's did not seem that high in the region of 300-400, on cruise, the only time I got decent egt's was at about 3000 rpm with 1.8 bar of boost when it hit 600.

Oldandconfused wrote:

IRBails wrote:

Oldandconfused wrote:

IRBails wrote:

Wilf still a mystery to me, are you saying regens are based on oil dilution, which still would require some sort of test ? I meanhow does the vehicle know the oil is diluted with out some sort of internal test ?

Part of the re-gen process is to introduce excess fuel so that some unburnt fuel enters the filter to create heat in the filter to burn off the ash. It's the process of intoducing the excess unburnt fuel which allows it to enter the oil, thus diluting it. More short trips=more diesel particulate build up in the filter=more frequent re-gens=more diesel in the oil (=premature engine wear?).

The DPF filter is in the exhaust so I can't see how the regen process adds fuel to the oil? So I am still confused, I think the service intervals are most likely a software algorithm , Land Rover seems to be pretty average when it comes to software, but would love to believe it is active monitoring which would really be the best for engine life .

Found this, hope it helps;
"During active filter regeneration, the exhaust gas temperature can be increased by combusting an additional quantity of fuel either (1) in the engine cylinder, or (2) in the exhaust system, upstream of the filter. In the first approach, the fuel is introduced through late cycle injection (post-injection) using the fuel injection system of the diesel engine. In the second method, fuel is introduced to and combusted in the exhaust system using specialized hardware".
.No1 is when driving, I understand that some of the excess, unburnt fuel can flow past the piston rings? into your oil thus diluting it.
I don't fully know the precise mechanics of it, I just knew enough to avoid it

Bye the way my oil changes have all been at the right time except for the last which was about 1500 miles short. As stated I have requested oil test so I will let the group know the results. I am running the V8 diesel so in the minority here. It does seem that if the regen is the issue and caused oil dilution it isn't the oil dilution that triggers the service required but the number of regens? So the real issue is why is the regens being triggered, firmware I suspect. Reminds me of the OP who had constant regens and was told it was his driving , all points to a fault in the diagnostics. M16 SVD8 ,4.4 HSE with a few extras, Sold R50 , Wife SQ5 , BMW R1200GSW.

These engines were never designed to have DPF's and because of that they are not optimally located in the exhaust systems. They don't get consistently hot enough to burn off the ash without a re-gen. I, briefly, had a 1.6 Honda Civic with the Euro 6 engine which was designed with a DPF by placing it next to the exhaust manifold so it got hot quicker. That being said, in the 9 months I had it, it still did 2 re-gens. Go figure eh.

According to my oil test I had 6% dilution, not good. I am waiting for the full results. Also doesn't seem to be markers for syn. oil. All services done by dealers which I would assume would use the right oils as they are LR dealers. Need to get another sample done now to see if this is ongoing. M16 SVD8 ,4.4 HSE with a few extras, Sold R50 , Wife SQ5 , BMW R1200GSW.

Found this interesting read. Of note the stop start function which I turn off is not good for Fuel dilution , DPF cycles are also mentioned. I think I will go to 15,000 k oil changes now.

http://www.dieselhub.com/maintenance/fuel-dilution.html

Wondering if there are LR specification for oil tests. I see from my research that many equipment manufacturers give this data. M16 SVD8 ,4.4 HSE with a few extras, Sold R50 , Wife SQ5 , BMW R1200GSW.