Easy question but just want to make sure

Daff_Duck · 31 Jan 2012 at 14:48

Ok please dont flame me for this, but. is it normal for your fuel consumption to plummet like a rock in the winter months?

The reason I ask is that I can remember the last time my fuel consumption,given that I drive on the same route each day, was so p poor. I know that various things affect fuel consumption but I am loosing @ 15mpg.. which is not impressing me at all given I travel @ 18K per year.

Its not biggy just wanted someone to say "Yes" then I can relax

burns · 31 Jan 2012 at 14:51

No, that is not normal. PANIC!

Seriously though it sounds like either you are driving differently, traffic is different or something is broken.

Mud · 31 Jan 2012 at 14:56

You're down 15 MPG from what? 60MPG -> 45MPG would worry me less than 25MPG -> 10MPG.

Clarkey · 31 Jan 2012 at 14:57

IF it were a bunch of short trips from cold start then yeah, but at 18k/year that's probably not the case so yeah, it's broken.

Minstadave · 31 Jan 2012 at 15:07

I've seen a good drop from 40 to 35 mpg if not more this winter.

Daff_Duck · 31 Jan 2012 at 15:15

Ok I usually get (and I do the same journey same speed day in day out) 55mpg and now I am getting just over 40 mpg but I can't figure out what has changed it all seems to have gone pear shaped since I had the car serviced (annual 10k).
Just a random thought here so again be gentle would the type of Oil used have any effect? The Car is an Audi and I am assuming that when they said synthetic oil that is just normal oil? Can normal oil be put in an Audi and then synthetic after, ie next service?

Other than that,where should I start looking to see if I can identify the culprit its costing me an average of £200pm in diesel alone at this p poor rate. I dont bomb down the motorway I set my car to cruise C at 60mph and try to keep at that speed.

Daff_Duck · 31 Jan 2012 at 15:20

Or just another thought is it the ECU letting in too much air to the mix and not shutting off? Please dont say that it might be the ECU as well thats like writing a blank cheque to find out the problem, I know you can use VAG com

Firestar_3x · 31 Jan 2012 at 15:21

Deflated tyre, stuck caliper, illegal immigrants clinging underneath.

rodenal · 31 Jan 2012 at 15:22

Something doesn't quite sound right tbh if you're certain nothing else has changed - I see about a 5mpg drop overall in the cold weather in the Civic diesel.

Daff_Duck · 31 Jan 2012 at 15:26

stuck caliper ..mmm mind you though that happens every winter,(my sensors come on and go off when the car is started, I think its due to them binding and then releasing as the alarm goes off after a couple of seconds) This is begining to worry me now as 15mpg is killing me fuel wise and I need to sort it out, were ever possible so come on gurus. Give me sone ideas of were to start looking

rodenal · 31 Jan 2012 at 15:42

The basics like tyre pressures (which you know how to check...i hope

) and calipers are the best initial places to look.

After a journey home put your hand over each corner (don't touch the disc) and make sure one wheel isn't hotter than the others. You could also find a quiet bit of road, get up to a decent speed and brake heavily - if the car pulls that's a good indication one has gone/going wrong

Hagar · 31 Jan 2012 at 15:59

rodenal said:
Something doesn't quite sound right tbh if you're certain nothing else has changed - I see about a 5mpg drop overall in the cold weather in the Civic diesel.

Similarly. My Civic 2200 diesel loses about 3-5mpg (5-10%) between normal weather and lots of subzero running. Could be the density of diesel fuel in cold weather?

ins0mn1ac · 31 Jan 2012 at 16:00

Over this and last winter I've gone from 10quid per week fuel in the summer, to 15 in the winter

GravyMonster · 31 Jan 2012 at 16:38

nkata said:
Could be the density of diesel fuel in cold weather?

My understanding is that it's the other way around - because cold air is more dense the engine injects more fuel to keep the engine from running lean. Could be wrong though, IANAM.

Unbeliever · 31 Jan 2012 at 16:56

Mine went from 35 ish to work and back to 27. Turned out my rear calipers had seized. Worth checking them out.

breadturbo · 31 Jan 2012 at 21:08

price of diesel going up rapidly doesn't help much either, my diesel cost's have rocketed to about 100k a year

Brookert · 31 Jan 2012 at 21:13

breadturbo said:
price of diesel going up rapidly doesn't help much either, my diesel cost's have rocketed to about 100k a year

I take it you drive something a little bigger than a 4 door saloon then

Aero · 31 Jan 2012 at 21:16

Run the air con much in winter?

Luke · 31 Jan 2012 at 22:29

~5mpg = normal.
15mpg = something is very wrong.

Jono8 · 31 Jan 2012 at 22:30

I would expect a bit of a drop. Say 2/3mpg. 5 at the most.

15 is too much for it simply to be the colder weather i would have thought.