If your vehicle doesn't have a DPF then the dealer may have changed to an oil suitable for use with DPFs because of the number of cars with DPFs so you may want to get a fresh sample for reference.
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Hi Graeme, my car does have a DPF and the service records state the oil they've used as being Castrol Edge Professional 5W30. However, I'm going to ask them to show me the actual drum in the workshop this time and I'm going to test a fresh sample as you suggest, especially as the viscosity figures are coming out consistently like it's a 0W30 oil [wink11]
For 10000 km, the wear metals and soot are quite high for a modern engine. I'm half of that with a 200TDI and a quarter with a more modern VW diesel.
Is that oil even a real diesel engine oil? This stuff? EDGE 5W-30 A3/B4 | Castrol EDGE - Car Engine Oil | Castrol Australia | Castrol EDGE | Castrol Car Engine Oils | Edge, Magnatec and GTX ranges | Engine Oil | Castrol Australia | Castrol™ Engine Oil & Lubricants - Castrol™ Australia I certainly would not be using that in a diesel. CF, A3/B4 is pretty crap.
Back to the silicon problem. You need to look closely over the intake system and the crankcase ventilation system. It does not take much. I'm sure it will all be plastic and cracked plastic is pretty common.
Interesting. Your fuel dilution is also too high . Thats not good. mmmm.
For dirt ingress I tend to look at a combination of aluminum and silicon (or at work being an iron ore mine - iron[wink11]). I agree with some of the above comments that it would be fairly uncommon to see silicon as a result of a failing seal - if silicone appears on its own I would normally link it to RTV gasket material or something similar. If the panel filter seal is looking ok then check over the rest of the intake system carefully.
Also I tend to agree that the fuel dilution levels are excessive, especially for 10,000 odd km, looks to me like its affecting the viscosity somewhat. Theres also a decent drop in the TBN in the sample to the right so that one looks to have done a few more km, or is a different oil to the previous ones (not sure if latest sample is on the right or left - Im assuming the right)
Nice to know I'm not the only weirdo regularly testing my vehicles oils[thumbsupbig]
I wonder if the EGR is having issues? Contributing to the increased soot levels?
The other source of silicon in the engine is dirty workshop procedures, adding dirt with the oil or when checking the level!
Thanks guys for the continuing suggestions, keep 'em coming!
And to answer some of your queries...
Yes, Rick has the right oil, it's https://msdspds.castrol.com/bpglis/F...PXE-AEWFE7.pdf and as he says it's what is specified by JLR for my engine so I don't have a lot of choice as it's being serviced by the dealer and still under warranty. Red, the one you linked to is a non-DPF oil. I also wrongly said it was ACEA A3 earlier in the thread but it's actually C1.
In fact the lab have used the wrong base viscosity numbers so showing mine as amber warning whereas it's actually pretty much bang on spec, so no worries there.
And as for the oil dilution, I'm not worried by the 3% for a number of reasons. Firstly I took the oil sample immediately after a DPF regen, and those tend to dump fuel in the oil which gradually evaporates off until the next regen when it dumps a load more, so I expect my average dilution is a lot less. Secondly, the lab don't use a very accurate test method for determining it, they basically stick a lighted match over the oil and guestimate the fuel content by the size and duration of the flame, so I don't set much store on a one-off result. Lastly, many owners of Disco Sports with the new Ingenium engine are experiencing oil dilution of above 7-8% so mine is minor in comparison.
Apart from the dreaded EGR, I'm guessing soot is quite high in the last two results (and yes the latest results are on the right) because recently it's had a lot of about town use and the only long journeys have been towing a caravan.
Still haven't found any obvious point where dirt is getting in the air intake system, so will probably just highlight it to the dealer and let them check it as it's going in for service next week.