Ian, do you deliberately apply some or all of the driving techniques described in your second paragraph? Do you include one journey of at least an hour every 200 miles or so? If you are doing neither of these things, then you are very lucky to be getting < 0.5% dilution / 1,000 miles on journeys of 30 minutes. In October 2017 even the manufacturer didn't think that that was possible. The following timings are based on the manufacturer's definition of "normal" driving for this model and draw on i) the letter from JLR Executive Office; ii) dealer comments attributed to a named JLR powertrain engineer; and iii) the May 2015 DPF Operation Manual.Ian_S wrote: ↑Fri Jun 14, 2019 11:16 amCan't agree with some of the above.
You do not need to have a journey time of at least 45 mins to get better than 6,000 to 8,000 miles between oil changes. My journey's are mostly 30 mins in duration and I managed to get around 13,500 miles before hitting 6%.
Driving hard doesn't mean a lack of respect for speed limits. You are allowed the take the car out of automatic mode to increase the engine rev's instead of just pressing the loud pedal harder to achieve the same thing. 7th gear on the 9-speed auto will keep you above 2,000 rpm without destroying fuel economy completely. It also reduces 'lugging' which is especially prevalent in top gear cruising on a motorway and is compounded further if you then only ever gently accelerate to overtake from say 65-70 as the gearbox may not change down. This style of driving can increase soot generation. You can also accelerate more quickly generating load than always accelerating gently (also helps the auto box realise it needs to change down quicker). It's debatable whether getting up to speed quickly and then maintaining speed is better than taking ages to get there in the first place.
10 minutes driving from cold is required to get the whole system up to operating temperature. During the warm-up period it's normal ignition, LP EGR Valve Open, no post-injection, no DOC light up.
10 minutes initial post injection with retarded ignition to light up the DOC and increase the temperature at the front face of the DPF to 580 deg C. (source: JLR powertrain engineer and LR DPF Ops Manual p1)
15-20 minutes post-injection to maintain the oxidation temperature to dispose of all HC/PM particles within the DPF. (source: LR DPF Ops Manual p 1)
Total 35-40 minutes.
My journeys were generally all over 30 minutes and included regular back-to-back 90-120 minute commutes on trunk roads and motorways, avoiding aggressive acceleration (it's not Milan after all) and complying with national speed limits (that's true GPS speeds, i.e. indicated 75 on a M-way). When they sold it to me with a written promise of servicing costs limited to about £500 every two years, no-one mentioned that I was expected to over-rev the engine, delay gear changes, accelerate hard or perform over-take manoeuvres like Lewis Hamilton. As I remember, it was quite the opposite because the car used to chivvy me into changing up earlier than I would normally have done with a little symbol on the IC (mine was a humble 6-speed manual).
This "normal" driving style earned me a dilution rate of 1% per 1,000 miles give or take and I think the posts on here prove that I was not alone. As I have demonstrated, the average distance to an oil change is actually only 8,300 miles.