XC70 D5 poor MPG

lotuscorty · Feb 5th, 2020, 23:05

2010 XC70 geartronic 205 D5 currently reading 23 mpg on the OBC. Recently had a boost pipe fixed, drives well, no codes or issues, just drinking fuel. Granted mostly about town, but economy is worse than the old Xc90 I just replaced with this.

It has been suggested that changing the thermostat may help, but since it is costly to replace, is there anything I can check before doing this? What temp should it run at?
Anyone else had the same issues? Thanks

Kev0607 · Feb 5th, 2020, 23:20

Has it been serviced recently? If not, that might be a good place to start with a new fuel filter, air filter etc.

XC90Mk1 · Feb 5th, 2020, 23:41

Quote:

Originally Posted by Kev0607

Has it been serviced recently? If not, that might be a good place to start with a new fuel filter, air filter etc.

I was going to suggest air filter and service. That said I don’t believe that alone could make that poor consumption.

IronJaw · Feb 6th, 2020, 06:01

What tyres are fitted to it? Certain types of tyre can effect MPG. Also it’s worth jacking up each corner and rotating the wheels to check you’ve not got a binding brake. I’ll assume you’re not driving round with a roof box on, but if you were that wouldn’t help MPG.

lotuscorty · Feb 6th, 2020, 07:51

Has been serviced and made no difference, genuine parts too. Tyres are Pirellis and are not m&s or winter, however I don't believe tyres would make it that bad?
Thermostat argument seems the most plausable?
If the car is driven at all spirited it is very low 20's, although it hasn't had a good run of over 40 miles in a while

Sotosound · Feb 6th, 2020, 08:20

Most diesels engines are slower to warm up than petrol engines when under a light load, so your car might not hit full working temperature during short journeys. That'll hit MPG.

Having said that, I've also found that diesels very quickly hit working temperature if they're whizzing along at higher speeds.

It's also possible that your old XC90 got up to working temperature more quickly because it was a heavier car, and the engine was under a heavier load at all times.

(An early XC90 auto that I borrowed once had a very short first gear, which I suspect was needed in order to get that very heavy vehicle moving.)

If your thermostat is dodgy then I'd expect the car to either overheat or to take an age to reach full working temperature, even on a fast road.

So, what does the temperature gauge say?

Others members may offer a different perspective and, as ever, YMMV. (And it clearly does.

)

Sarah Booth · Apr 27th, 2021, 10:27

I have the same issue so am interested in what you find out. I have owned my 2005 XC70 D5 for 6 years and then over the last 2 months we have had a reduction from an average of 40 mpg to 33 mpg with no difference in use, this included long motorway runs??? It has been serviced at home as usual with all filters done but it has made no difference. I noticed it is running slightly noisier on idle when I start up. Only had its MOT 3 months ago and runs cleaner than air (fast pass as usual). It has 133K on the clock. Everything when driving is good and we have a diagnostic box which hasn't given any faults, just had record of issues with brakes which was sorted. Not sure what to check next??

V70Zig · Apr 27th, 2021, 17:37

Quote:

Originally Posted by Sarah Booth

I have the same issue so am interested in what you find out. I have owned my 2005 XC70 D5 for 6 years and then over the last 2 months we have had a reduction from an average of 40 mpg to 33 mpg with no difference in use, this included long motorway runs??? It has been serviced at home as usual with all filters done but it has made no difference. I noticed it is running slightly noisier on idle when I start up. Only had its MOT 3 months ago and runs cleaner than air (fast pass as usual). It has 133K on the clock. Everything when driving is good and we have a diagnostic box which hasn't given any faults, just had record of issues with brakes which was sorted. Not sure what to check next??

Hi Sarah,
Your not the first and won't be the last...wrong section, try posting this here - https://www.volvoforums.org.uk/forumdisplay.php?f=19
This section is for later cars.
Good luck

yostumpy · May 19th, 2021, 16:53

When I picked up mine, 6 weeks ago, the readout ( long term) was 33.7 mpg. I think the previous owner must have been heavy footed, as at the moment, on half a tank, it’s reading 46.2. Some local, some m/way. But then I do like to hypermile, it’s fun.

Feb 5th, 2020, 23:05	#1
lotuscorty Junior Member Last Online: Jun 28th, 2020 14:43 Join Date: Apr 2006 Location: Glasgow	XC70 D5 poor MPG 2010 XC70 geartronic 205 D5 currently reading 23 mpg on the OBC. Recently had a boost pipe fixed, drives well, no codes or issues, just drinking fuel. Granted mostly about town, but economy is worse than the old Xc90 I just replaced with this. It has been suggested that changing the thermostat may help, but since it is costly to replace, is there anything I can check before doing this? What temp should it run at? Anyone else had the same issues? Thanks

Feb 5th, 2020, 23:20	#2
Kev0607 Premier Member Last Online: Today 15:21 Join Date: Apr 2019 Location: Manchester	Has it been serviced recently? If not, that might be a good place to start with a new fuel filter, air filter etc. __________________ 2007 S80 2.4 D5 - 110,000 miles

Feb 6th, 2020, 06:01	#4
IronJaw Junior Member Last Online: Mar 3rd, 2020 17:36 Join Date: Oct 2019 Location: West Lancashire	What tyres are fitted to it? Certain types of tyre can effect MPG. Also it’s worth jacking up each corner and rotating the wheels to check you’ve not got a binding brake. I’ll assume you’re not driving round with a roof box on, but if you were that wouldn’t help MPG. __________________ 2008 Volvo XC70 D5

May 19th, 2021, 16:53	#9
yostumpy Senior Member Last Online: Today 15:12 Join Date: Mar 2021 Location: Gravesend	When I picked up mine, 6 weeks ago, the readout ( long term) was 33.7 mpg. I think the previous owner must have been heavy footed, as at the moment, on half a tank, it’s reading 46.2. Some local, some m/way. But then I do like to hypermile, it’s fun. __________________

Feb 6th, 2020, 07:51	#5
lotuscorty Junior Member Last Online: Jun 28th, 2020 14:43 Join Date: Apr 2006 Location: Glasgow	Has been serviced and made no difference, genuine parts too. Tyres are Pirellis and are not m&s or winter, however I don't believe tyres would make it that bad? Thermostat argument seems the most plausable? If the car is driven at all spirited it is very low 20's, although it hasn't had a good run of over 40 miles in a while

Feb 6th, 2020, 08:20	#6
Sotosound Premier Member Last Online: Today 15:35 Join Date: Dec 2013 Location: Aylesbury	Most diesels engines are slower to warm up than petrol engines when under a light load, so your car might not hit full working temperature during short journeys. That'll hit MPG. Having said that, I've also found that diesels very quickly hit working temperature if they're whizzing along at higher speeds. It's also possible that your old XC90 got up to working temperature more quickly because it was a heavier car, and the engine was under a heavier load at all times. (An early XC90 auto that I borrowed once had a very short first gear, which I suspect was needed in order to get that very heavy vehicle moving.) If your thermostat is dodgy then I'd expect the car to either overheat or to take an age to reach full working temperature, even on a fast road. So, what does the temperature gauge say? Others members may offer a different perspective and, as ever, YMMV. (And it clearly does. )

Apr 27th, 2021, 10:27	#7
Sarah Booth New Member Last Online: Apr 29th, 2021 10:37 Join Date: Apr 2021 Location: Doncaster	I have the same issue so am interested in what you find out. I have owned my 2005 XC70 D5 for 6 years and then over the last 2 months we have had a reduction from an average of 40 mpg to 33 mpg with no difference in use, this included long motorway runs??? It has been serviced at home as usual with all filters done but it has made no difference. I noticed it is running slightly noisier on idle when I start up. Only had its MOT 3 months ago and runs cleaner than air (fast pass as usual). It has 133K on the clock. Everything when driving is good and we have a diagnostic box which hasn't given any faults, just had record of issues with brakes which was sorted. Not sure what to check next??

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