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Life with a Land Rover Discovery: Month 4
Clogs and logs - 28th February 2018
Last time I briefly reported that the Discovery had been in for an unexpected service, so more on that now. It’s the kind of thing that I don’t think gets huge mainstream attention but sets owners forums twitching.
Basically, as far as I understand it, a car with a diesel particulate filter needs it declogging every now and again, by getting it hot enough to burn the soot out of it. Usually the car finds a time to do the cycle automatically, when the engine is running at higher revs – which is fine if your engine visits those higher revs.
I once heard, although it might be apocryphal, that London cab drivers didn’t always get their engines warm enough. They spent so much time idling around town that the DPF would soot-up and a light would come on suggesting they needed to go to the service centre to get it declogged. But the centre was in Southampton, so they’d get onto the M3 and, hey presto, one declogged filter.
Anyway, newer cars can apparently prompt a DPF declog, even at low engine speeds, by injecting more diesel at low revs to heat up the exhaust gases. When they do that, though, some of the diesel can seep into and dilute the engine oil in the sump. And if that happens too much, you need an oil change at intervals before the expected 20,000 mark.
I usually do lots of long-distance work so was at first a bit surprised that this car needed an early oil change. (Although putting the engine on ‘for a couple of minutes’ to warm up the interior and then dozing off in the back with it idling for about two hours during a 24-hour race probably didn’t help.) But anyway, Land Rover Milton Keynes did it all under warranty, and I’ve had a few emails since from people who’ve had similar, either completed under warranty or, once or twice, as something they’ve had to pay for, which seems mean.
Add to this the spectre of AdBlue diesel exhaust fluid, then. The Discovery’s thirst for this additive is about one litre per 350 miles or so – about the same as a couple of owners I’ve spoken to. It means I’m putting in a full 10-litre container at a time, every few thousand miles.
It’s not a huge faff, although the containers pour too fast for the filler neck and the container spout leaks around the thread, but it’s not something you’d bother going to a dealer for. Given all this complexity, though (Håkan Samuelsson at Volvo thinks hybrids will soon be cheaper to make than diesels), maybe it’s no wonder that it doesn’t take many scare stories and the threat of taxation to suddenly hugely dent the popularity of diesel.
Which is daft, because no petrol non-plug-in hybrid alternative would get close to the ability or economy of the diesel V6 in a car of this size or capability. I haven’t stretched its abilities since it stopped snowing, suffice to say it’s a brilliant late-night, home-from-the-airport motorway car that is impeccably stable, quiet and comfortable.
But I did call on it the other day when I’d been chopping logs. Lots and lots of logs, which needed moving from a field to my back garden – a distance of only 50 yards but not a trip I wanted to walk 100 times, two stumps in hand each homeward leg. I’d feel bad doing this to a typical £70,000 luxury car, and they probably wouldn’t get through the mud anyway, but with the Discovery I could chuck in a tarpaulin and remind myself that, well, it’s a Land Rover, after all. I just hope it didn’t spend too long idling.