D3 to D4... what to be aware of

[conanius]

Hi Folks,

Currently have a 2006 (56) HSE Auto 2.7 diesel. 178k miles and we fancy an upgrade.

Going to look at a 2015 (Euro 6) HSE Auto 3.0 diesel. 100k miles, 1 owner, FSH, etc. Just had the belts done, Looks great.

I know there is a quite a bit of change D3 to D4, and then seemingly near year on year incremental change on the D4 until it stopped in 2016. It appears it should be quite an improvement for on road driving (Suspension, brakes, performance, refinement - non exhaustive)

I'll obviously find out tomorrow when we drive it, but I'm expecting good things. Anything that people suggest to particularly look out for / test?

Particularly interested in anyone who has done a similar transition and how much difference we will notice day to day on boring things like fuel economy - we currently average 27 ish on the D3, I'd like to think we could break 30 with the D4....

[conanius]

Thought I'd better update this for future people considering the change.

Short version - we put a deposit on a 2015 euro 6 D4 HSE. Not the one mentioned from my first post, but another car they had just got in and haven't finished prep on.

It's a huge change from the D3, but I won't rush to judgement and say it's simply better everywhere. I still see the D3 has a place for people with certain requirements.

What I will say, is the overall experience is far closer to a 'refined SUV' when driving on the roads. Quicker, quieter, generally more refined ride and handling, and seemingly better fuel economy.

We collect it in a couple of weeks.

[A.J.M]

A D4 is a D3 with some updates, tweaks and some different issues added to the mix.

If you have owned the D3 for a while then you’ll know the usual weak issues.

D4 adds some lovely ones like split inlet manifolds ( £1300 or so to fix both ) the rotary gear selector can fail and the good old glass crank can snap.

[bakerstreet]

conanius said:

Hi Folks,



I know there is a quite a bit of change D3 to D4, and then seemingly near year on year incremental change on the D4 until it stopped in 2016. It appears it should be quite an improvement for on road driving (Suspension, brakes, performance, refinement - non exhaustive)

I'll obviously find out tomorrow when we drive it, but I'm expecting good things. Anything that people suggest to particularly look out for / test?

Particularly interested in anyone who has done a similar transition and how much difference we will notice day to day on boring things like fuel economy - we currently average 27 ish on the D3, I'd like to think we could break 30 with the D4....

Doubt it will break 30 if I'm honest. Still 2600Kg and the same shape

Suspension
Its my understanding that its identical to your D3

Engine and Gearbox
These are the biggest changes under the skin and where you should exercise some caution.

Gearbox is the 8Sp which is considerably more reliable than the 6Sp in the D3 and early D4. Better on economy too.

The engine is considerably more powerful than D3 with nearly 60bhp more....However, they are not known to have issues with the cranks and servicing every 50 miles will make no difference on if it happens or not. A rebuild is £4-9K depending on where you go. Some warranty companies will cover it, some won't. QP Online are one of the best engine suppliers/installers out there so worth noting down if it does go pop.

Other issues are fuel tank senders and inlet manifolds as well as all the usual diesel issues such as injectors, EGRs and Turbos.

Other than that, its the usual D3/D4 issues:
Wheel bearings
suspension arms
Air suspension in general (Compressors, sensors, air tank, axel valve blocks)
Leaks

D4 interior is vastly better than the D3 though and the D4 is still a great piece of design

Last of the D4s had DPF too, so thats another thing that will go wrong with lots of short journeys.

Worth getting an insurance quote first as the D4 was keyless from 2009 and they keys are easily replicated and premiums are through the roof for any Keyless start LR now and in some cases insurers are just refusing to even quote. I've been reading stories of people in the home counties have to pay triple the premium compared to last year because it was the only company they could find!

[KPB1973]

Re: MPG, they can report decent economy of high 30s on a gentle run, but in my experience the trip computer over estimates by about 15%.

I manually calculated one brimmed tank (mostly extra urban driving) and it had done bang on 30mpg, vs the recorded 34.6mpg average.

If you've got good anticipation of braking zones, coasting and use the weight of your car to your advantage, then they're not too bad on fuel. You do quickly learn a driving style to suit them (particularly managing the lean through corners) and the gear ratios are pretty well judged once you're up above 30mph or 3rd gear. I always found mine to be a bit strained below that.