Buying a diesel, what's different from petrol?

[onq]

The PSA Diesels [Peugeot/Citroen] once led the way, but the Honda Diesel is supposed to be amazingly refined.
We've seen a lot of Nissan Quasqai [sp?] 1.5CDi Diesels around and people speak well of them in terms of style, substance and fuel consumption.
Other diesels like the Volve V50 look the part but performance figures seem poor in comparison and the heavy doors make the interior relatively cramped for my frame anyway.

However if you're considering economy driving in narrow city streets and unless you're lugging a large family everywhere, the 1.4litre TSI DSG Golf Petrol with 7-speed transmission should be on your list of cars to check out.
Far nippier than the diesel opposition its reportedly just as frugal - plus its a Golf!
Like any hi-tech engine this should be well warmed up before giving it throttle, and this one has both a supercharger for low end power and a turbocharger for top end, regulated electronically to give a good power spread.

Don't judge on economy alone and make sure you take whatever car you're considering on a full test drive representative of the type of driving you do before making that final choice.

ONQ.

 

[sse]

Diesels are not the paragons of reliability they once were.

Avoid any diesel that has a particulate filter (DPF).
Avoid any diesel that has a dual-mass flywheel.
Avoid any common-rail diesel that has been run after mis-fuelling (modern Fords, for example. prevent this). If buying from a dealer get a cast-iron guarantee from them that this hasn't happened.
Avoid any diesel that has had its service intervals stretched to the full 2yrs/30000km.

A standard (torque converter) auto gearbox will be much less efficient than a manual gearbox - which will have long-legged higher gears. Check out the CO2 ratings. Many CVT gearboxes have had problems with the torque of a diesel engine in low gear - Audi's multitronic in particular. Buy an after-market warranty as a failure will probably write the car off. If test driving an automated manual make sure you try low-speed manouevers such as parallel parking or trickling forward in traffic, you may change your mind.

Can't go wrong with a nearly new 320d!

SSE

 

[Guest128]

You were unfortunate in that you drove probably one of the worst diesels out there.Fuel consumption is no great shakes either!!

Compared to the 20MPG from the Mazda RX-8 i'm looking to buy i'd say the Avensis wasnt too bad on fuel

 

[krissovo]

Avoid any common-rail diesel that has been run after mis-fuelling (modern Fords, for example. prevent this). If buying from a dealer get a cast-iron guarantee from them that this hasn't happened.
Avoid any diesel that has had its service intervals stretched to the full 2yrs/30000km.

You made some interesting points but surely you need to be psychic to tell if it has been filled up with petrol?

Also what is the issue with the servicing interval?

 

[sse]

Well you're always taking the risk that the car has been mis-fuelled if you buy second-hand. The problem is that any warranty claim for the fuel system will likely be rejected unless you get a specific guarantee from the dealer. For a private sale there's nothing you can do.

Regarding service intervals a diesel contaminates its oil (jet black after 100 miles) and after 30000km even a fully synthetic oil will be wrecked. Most if not all diesels have gas recirculation valves which will result in engine runaway if they stick open. I'm always amazed at the number of people who pay 40k on a car and skimp on €50 oil changes.

SSE

 

[MandaC]

However if you're considering economy driving in narrow city streets and unless you're lugging a large family everywhere, the 1.4litre TSI DSG Golf Petrol with 7-speed transmission should be on your list of cars to check out.
Far nippier than the diesel opposition its reportedly just as frugal - plus its a Golf!


ONQ.

Combined Figures for the 1.4l TSI DSG Golf are approx. 6.0L per 100km, where its diesel equivalent returns 5.4L per 100km. Without the DSG option, the Golf 2.0 tdi returns 4.9L per 100km. Its a cracking car to drive.

I had a 1.4tsi engine (without DSG) in my last car(not golf) and I was averaging 35 for 500kms. Now with a 2ltr diesel engine, my fuel consumption for 500kms is 25 per week. The 1.4 tsi would be faster off the mark than the 2.0Ltr diesel I have now, but there is not much in it.

The comment about not bothering to do the oil could be directed at me, thanks for the tip!

 

[OkeyDokey]

Diesels are not the paragons of reliability they once were.

Avoid any diesel that has a particulate filter (DPF).
Avoid any diesel that has a dual-mass flywheel.
Avoid any common-rail diesel that has been run after mis-fuelling (modern Fords, for example. prevent this). If buying from a dealer get a cast-iron guarantee from them that this hasn't happened.
Avoid any diesel that has had its service intervals stretched to the full 2yrs/30000km.

Can't go wrong with a nearly new 320d!

SSE

Interesting post. Can you suggest any other brands and models in addition to the 320d?

 

[sse]

530d?

As other posters have said, the latest Honda 2.2 is supposed to be very good, plus there's an auto on the way for the Accord and CRV (we will almost certainly get one of the latter).

From personal experience I've had a Clio 1.5dCi which never put a foot wrong, plus a Golf 1.9TDi PD which was like driving a rattly tractor, although it was fast. From test drives I was amazed how unrefined the newish VAG 2.0 TDi was, at least in an A4 and the less said about the ancient 1.9 the better.

Check out honest john for the scoop on DPFs and DMFs, and why you need to tread carefully when buying a diesel 2nd hand.

SSE

 

[positivenote]

Im considering upgrading to a 320d or a 530d at the moment although they will be older models (03-04). Apart from the obvious tax diff and power is there a huge amount of diff between the two. Id cover about 600miles a week mostly secondary roads with some motorway. Im also seeing cars of 100K + on their clocks should i try and stay below this mileage? ive around 10-12k to spend.
Thanks in advance