Why are diesels are suited to motorway miles?

sevenhills

Why are diesels are suited to motorway miles?


I assume the above is true. In the old days, petrol cars had a manual choke, I guess they still do the same thing, but controlled by the cars computer.
Do diesels have some form of choke that makes them more suited to longer journies?
I have just bought a Euro 5 1.7 diesel Zafira, so with my low mileage, I need to learn about them.

Roland_Sausage

You maybe should have learned about them before you bought one.

tberry6686

read up on dpf's. Low mileage diesels used for short runs are a really bad idea

sevenhills

tberry6686 wrote: »

read up on dpf's. Low mileage diesels used for short runs are a really bad idea

I just completed this quiz, it said that I am suited to buying a diesel!


https://www.rac.co.uk/drive/advice/buying-and-selling-guides/petrol-or-diesel/

DUTR

sevenhills wrote: »

I just completed this quiz, it said that I am suited to buying a diesel!


https://www.rac.co.uk/drive/advice/buying-and-selling-guides/petrol-or-diesel/

How can it know? The questions are rather vague, but no mention of choke as per your opening post, as an aside my last car to have a manual choke was a 1978 Triumph Dolomite.

Ebe_Scrooge

Aside from the DPF issue which is a valid point (motorways are a lot kinder to a DPF than town driving), it's also to do with the number of miles you do. Diesels - very generally - get better MPG than a petrol engine (yes, there are many petrol engines these days that can rival a diesel in fuel consumption, but it's a very broad generalisation). But a diesel costs more to buy in the first place than its petrol equivalent, and the fuel costs more. So you have to do a lot of miles before the increased MPG offsets the additional costs. I think the rough rule of thumb always used to be about 20,000 miles a year.

And diesel engines always used to be a lot simpler than petrol engines - change the oil regularly and there was not much that could go wrong. Sadly it's not so much the case these days, what with DPFs, DMFs, electrical gubbins and what-not. But in the olden days a diesel engine would last forever with very little maintenance, it would far outlast everything else on the car.

Herzlos

Diesels tend to be more efficient with more low down torque, but need longer to warm up. So it's more a case that diesels aren't very good with short trips - it clogs up filters and it never gets up to proper temperature for peak efficiency.


Low mileage on a diesel isn't too bad if it's infrequent but longer trips, it can be pretty terrible if you're using it to drive a mile to a shop and back twice a week.


They are a lot better at forcing DPF regenerations now (the burning smell you'll experience when the engine doesn't turn off).

RichardD1970

sevenhills wrote: »

I just completed this quiz, it said that I am suited to buying a diesel!


https://www.rac.co.uk/drive/advice/buying-and-selling-guides/petrol-or-diesel/

I just had a go and got diesel.

Below average miles per year, short A&B road driving, mainly city. The antithesis of diesel I would have thought :rotfl:

alan_d

sevenhills wrote: »

I have just bought a Euro 5 1.7 diesel Zafira, so with my low mileage, I need to learn about them.

You have my sympathy. I've had the misfortune of working on a friend's one several times. A truly horrible car. So much stuff that is just poorly designed and cheap/nasty.
EG the rear brake caliper slider bolts that won't come out completely without first removing the hydraulic line. And you can't fit a ring spanner or socket on because the pipe union is in the way - so risk of an open-ended slipping.
Or the fine threaded bolts (M8x1.0) that mount them, when most replacement pads come with M8x1.25 thread... and a reasonable chance the ape that worked on it previously fitted the (wrong) replacement bolts and forced them in, so the bolt then shears off when you come to remove them years later.
Or the stupid spare wheel carrier.
Or the heater matrix pipes with rubber seals made of cheese that leak.
Or the injector leak-off pipes that have plastic 'T' pieces in each injector that get brittle with age/heat and break off.
Or the poor access to the brake fluid reservoir.
Or the cables into each door that fatigue, causing locking/windows/speakers to stop working.
Or the various fire related risks that they have been recalled for.
And on top of that, it's pretty awful to drive.

Mercdriver

Reading that makes asking advice about a car you've already bought a bit like checking flight prices after you have bought an inflexible ticket. Unfulfilling and ultimately painful.

prowla

Diesels return a higher mpg than petrol, so can be a money saving for people who regularly drive distances.


Diesels tend not to like just being used for short journeys (as some folks have said).


Diesels are dirtier than previously thought, partly because of the car makers trickery in fudging the emissions testing.



I recently bought a new car and the sales folks were trying to push diesels, but I wasn't interested.