V40 mpg dropping off a cliff

[denecaster]

I have a 64 V40 D4.

When I got it in May this year, the average mpg on the dashboard was something like 49. Over the summer, that gradually rose to a peak of 54.9, but settled at 54.6, doing a mix of mostly motorway driving, but some country roads and the occasional short local trip.

The actual mpg, calculated using mileage and how much fuel it took to fill a tank, was around 54-56.

During October, I was off work for a month with an injured shoulder, and most of my trips were local.

Obviously, the mpg fell.

I've been back at work for a month now, and it's back to a mix of motorway and country roads

But the mpg has continued sinking like a stone. The dashboard is now saying 51.6, and after just filling up, the most recent mpg was 46!!

Eh??

I must be doing something wrong somewhere. That's nuts.

[JJD1]

Outside temp ?? Change diesel filter

[Whippy]

Yeah, outside temp has a massive effect on how much dinosaur squeezings you use. My car will drop from low fifties to low forties in the winter.

[denecaster]

Really? Wow. Never experienced that effect on any of my cars before, but I'll take your word for it.

Thanks, I'll keep an eye out for that now, then.

[Boatie]

I assume they still put anti waxing additives into diesel in the winter. Anyone an idea of how much by volume? I assume it has an effect. May be wrong .

[Familyman 90]

Originally Posted by denecaster

Really? Wow. Never experienced that effect on any of my cars before, but I'll take your word for it.

Thanks, I'll keep an eye out for that now, then.

You will have experienced it, you just haven't noticed it. P