JLR and Oil Dilution

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Fri 1 Mar 2019 18:40
- Engineer Andy
VAG, JLR and diesels certainly get a roasting this week!
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Fri 1 Mar 2019 20:43
Honest John’s Motoring Agony Column 02-03-2019 Part 2 - spsrich
VAG, JLR and diesels certainly get a roasting this week!

deservedly so !

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Sat 2 Mar 2019 00:17
JLR and Oil Dilution - Kath Hunter

The problematic oil dilution on some diesels (particularly the JLR models mentioned) happens because they have to rely 100% on post injection to oxidise the soot stored in the DPF, as stated. But the diesel dilution is occurring continuously DURING the post injection "burn", not just when the engine stops. Interrupted journeys just make the problem worse because there is a wasted period of post injection (warming up the DPF to 600 C) when the regeneration has to be restarted to finish the job. There are 2 heat-related problems on the Evoque and DS: a) the cat doesn't get hot enough in normal driving for passive regeneration to operate (which means faster soot accumulation on the filter), and b) active regenerations take much longer to complete due to the elongated exhaust architecture. These 2 factors mean that active regenerations are needed twice as frequently and last for twice as long. This raises the probability of a failed regeneration by a factor of four compared to a car with a closely-coupled DPF like the Jaguar XF. But it is the fact that the post injection is running for four times as many minutes in every 500 miles that is the real root cause of the higher fuel-in-oil dilution, not the number of partially completed regenerations. That's why long distance driving at 65-70 mph is also known to cause higher than expected diesel dilution, leading to some Discovery drivers being told by their dealers to avoid motorways altogether in order to try and make their engines work harder.

KH

Edited by Kath Hunter on 02/03/2019 at 00:30

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Sat 2 Mar 2019 10:04
JLR and Oil Dilution - GingerTom

Hard to believe the engineers did not for-see any of this nonsense.

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Sat 2 Mar 2019 11:23
JLR and Oil Dilution - Engineer Andy

Hard to believe the engineers did not for-see any of this nonsense.

I suspect they did - I think HJ said in one of the replies on this issue (there are 3) that JLR used the platform from the old LR Freelander as the basis and its configuration mean they couldn't close-couple the DPF due to that the engines they were using. I would have thought that the engineers brought this to the attention of their managers, but the bean counters over-ruled them for changing things because it cost more money.

They may have saved on R&D by using the old platform, but are now literally paying the price of that (IMHO) stupid decision by having to shell out for many repairs and lost business due to the poor reliability of the brand and specific issues like this that are design flaws that cannot be fixed on the cars that have them.

Of course, this is not helped by them going full-on diesel and up-market just when diesels were starting to wane in popularity (before Dieselgate) due to this very issue and when world economic fortunes started to reduce, especially in richer nations. Bad calls all round, and to me, doesn't reflect at all well on the management at this firm.

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Sat 2 Mar 2019 12:03
JLR and Oil Dilution - stojom
Quite agree, all this nonsense about how manufacturers rigorously test their cars prior to production is just PR. Look how many have known faults a few years into sales. They have ample time to run them to high mileage to test reliability.
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Tue 5 Mar 2019 08:25
JLR and Oil Dilution - Marcus T.

Reliability does vary from one manufacturer to another, with Japanese vehicles generally being the most reliable. My neighbour works in R&D at Honda. He is involved in testing parts for vehicles two years before they go into production.

Edited by Marcus T. on 05/03/2019 at 08:30

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Sat 2 Mar 2019 08:57
- nrm1969
Skoda Superb Media System. For £2500 compensation it would be worth visiting a car audio specialist and seeing what kind of system they could fit.
I know Kenwood do bespoke units to replace standard fit VAG units in Golfs, etc and given VW 's part sharing there's a good chance a Superb uses the same unit as something else.
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Sat 2 Mar 2019 11:26
Honest John’s Motoring Agony Column 02-03-2019 Part 2 - Engineer Andy

I suppose it depends upon how interconnected the system is into other parts of the car's electronics - would having a new (different make) ICE system mean a loss of non-ICE features that the OEM system displays/controls?

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Sat 2 Mar 2019 23:03
Honest John’s Motoring Agony Column 02-03-2019 Part 2 - Irony

I would have expected the manufacturer to have already swapped the headunit, especially if they are offering £2500 !!! I find it incredible they are offering so much money - perhaps the problem lies elsewhere?

In any case, you can buy 3rd party systems which replicate the OEM functions ( plus lots more ) for around £1000 if not less.

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Sat 2 Mar 2019 10:02
- GingerTom
I think I would collect the Macan and sell it on asap despite any financial hit which would be preferable to a lengthy and expensive legal action or using a potentially dangerous car.
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Sat 2 Mar 2019 12:31
- That bloke
The Macan is on contract hire, so it is not the posters to sell
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Tue 5 Mar 2019 12:25
Honest John’s Motoring Agony Column 02-03-2019 Part 2 - GingerTom

Thanks. I missed that bit.

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Sat 2 Mar 2019 23:23
- Irony
VW Passat brake discs. I've heard several complaints about rusting discs - easy solution, replace with 3rd party discs next time.

But completely mystified by those tyres. Questioner is driving a heavy engine over the front wheels. That particular tdi is also very powerful during low revs therefore even with the most careful driver, diesels tend to eat front tyres when accelerating.

A 2.0tdi with 6-7mm tread on the original tyres after 36,000 miles? It could well be original tyres if the driver has been very careful, but the 6-7mm tread left? Sorry I don't believe it.

A brand new tyre has 8mm tread. If he's using 2mm per 36,000 miles that means he could potentially go for 108,000 miles on the original tyres and still be within the legal limit. What are those tyres made out of - tungsten?
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Sun 3 Mar 2019 10:04
Honest John’s Motoring Agony Column 02-03-2019 Part 2 - Captain-Cretin

My last set of new tyres had 10mm of tread; so your calculations could be way off.

I agree it does sound insane though, I barely get 12K from my fronts (Mitsubishi Grandis), even though I stopped driving like a mad teenager several years ago.

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Sun 3 Mar 2019 14:03
Honest John’s Motoring Agony Column 02-03-2019 Part 2 - RafflesNH

My Michelin PS4s only had 7mm tread depth when new.

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Tue 5 Mar 2019 08:28
Honest John’s Motoring Agony Column 02-03-2019 Part 2 - Marcus T.

Fronts on my CRV mk3 did nearly 50K miles. Michelin Latitude.

Current mk4 CRV gets 30K from Continental Cross Contact

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Sun 3 Mar 2019 17:22
- jchinuk
Re : Car Macanics, My immediate thought is that the writer is happy to accept (indeed pay for) the advice of a solicitor (an expert in the law), but not accept the advice of a dealership (experts in Porsches).
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