[Closed] diesel drivers

Poor fuel economy all the time for me, weather makes little if any difference. 20mpg out of mine 🙁
Is it due a service? Checked tyre pressures?

Yep, drops in the cold. And in this mornings -15 the car was struggling to start as well. Some of it is I think they put more additives in at this time of year.

Been @ -7 during day for a week now, -10/12 at night all week and even neat antifreeze in the second car that has been unused is a solid block of ice this morning.

Diesel doesn't burn well cold. In very cold countries they put different additives in to combat this. (AFAIK)

You tend to get worse fuel economy in all cars in this weather. Heater on, Clearing windows, more idle time and slower traffic all this contributes. I drop from an average off 49 to about -45 in the winter. Part of that is that I have an auxiluary heater(electric heater that eats up the water quicker than the engine does) and burns alot of power. That combined with the above and the heated seats I take a bit of a drop. Also I believe the fuel is colder so take more for it to heat up (remember diesels don't combust. However your Turbo will run better with colder air so you might get a small improvement in performance. The above is only based on my knowledge and someone will probably be alonmg to tell me I'm taking rubbish haha.

Yep, drops in the cold

Engine takes longer to warm up, big diesel blocks are worse for this, plus you tend to let it tick over as you de-ice the rest of the car.

Our petrol focus has dropped about 3mpg recently, but it's warming up within a mile and the cabin is warm in 2 miles. The 2.0tdi VW I've also been driving takes 4-5 miles to warm up to the same reasonable level.....

Nowt you can do about it really 🙂

The 2.0tdi VW I've also been driving takes 4-5 miles to warm up to the same reasonable level.....

Try the 1.9tdi, it takes longer as it doesn't have the auxiluary heater I was talking about above. (I also have the 2.0tdi Passat)

Jolly good. Was worried that the car may be goosed!

You'll get a v. slight drop in economy during the winter because the diesel has anti freezing/clogging additives in it. Other than that you're probably using more heaters/aircon/lights/heated rr screen (all use energy taken from the engine) and the engine needs spend longer to warm up to operating temperature.

On the plus side if the engine has an intercooler this doesnt need to work as hard as the cold air is denser and so the turbo can run a bit more efficiently. Probably doesnt make up for other issues, just reduces the impact a bit.

glad its not just me then... only had it fully serviced at the end of november and thought i might have to go back and ask whats up! not a massive drop but noticeable when looking how many miles i've done before filling up each time.

Mines dropped 4-5mpg, tends to be worse below -5 degrees, most of my 50 mile commute for the last 3 weeks has been in -10 or below. So god knows what that is like with wind chill at 80mph!

Yeah - mine seems to drop by about 4-5mpg.

I put it down to a combination of longer to warm up, running while defrosting the car some mornings, generally slower stop-start journies, more electrical load from heating stuff......

still... at least we can pull off in 3rd up an icey hill 😆

Ah see I disagree with that, I think the advantage of the diesel is that you can leave in 1st gear and almost dump the clutch, the wheels then spin for a second or two and then grip and the car moves off. No more wheel spin, no burning the clutch, more control etc etc

true true, in the end awe are better people for owning diesels, as long as those petrol people realise and bring me cake.

A few MPG lower here too, but I'm putting that primarily down to having the a/c on lots, the rear window heater, the heated mirrors etc, and spending a few minutes with the engine running in the drive every morning.

Saying that, on longer journeys it is a bit better, as I'm driving a bit more smoothly and slowly than in the dry, and using less acceleration than usual. Still getting mid 40s mpg out of the current tank, and reckon it'll be 50+ when I trundle down the M6 to Lancs next week, as I'll probably knock a little bit off my usual motorway cruising pace.

[i]Nowt you can do about it really [/i]

There is. Ride me bike 😉

Try the 1.9tdi, it takes longer as it doesn't have the auxiluary heater I was talking about above. (I also have the 2.0tdi Passat)

I can do the 22 miles to work in my 1.9TDi Golf and it just hits the 90 degrees mark as I go up the last long 1 mile hill.

There is no point in letting it sit idling for any length of time as it never heats up.

Last winter I left it ticking over and forgot about it, went about doing other things and remembered 45 minutes later. Engine had barely moved on the temp guage but MPG was about 5

Not noticed much difference in economy, but mine certainly goes better when its cold, like muddy@rseguy says it helps the intercooler do its job. Cold air is denser, so you can burn more fuel with the same volume of air, more fuel = more power. Might also account partly for the increased consumption

Yeah. Mine's awful. I was going to ask the same question. I've put twenty quid in since Monday and only driven about a 120 miles which is mental, normally that'll get me around 200 miles.