XC70 D5 poor MPG

[Tatsfield]

D5 is just a badge denoting a 5 pot engine

Apparently that is no longer the case. The D denotes a diesel engine but the 5 denotes the power range into which the engine falls. I suspect that at the top end of the power range the only diesel engines are the 5 pots but there are 5 pot diesels with D4 badging. There is a thread on here which delves into this D# badging nonsense. https://www.volvoforums.org.uk/showthread.php?t=249014

[Kev0607]

Originally Posted by V70Zig

D5 is just a badge denoting a 5 pot engine, there are engine variants for the D5 and might not be the same, putting the correct info into Vida should give you the right info.



I too have a bluetooth reader, because I don't have a temp gauge ! I have the torque and the car scanner apps on my phone to see actual temp.
From lotuscorty's posts it looks like his has unfortunately stuck in an open position which will fool the ecu into over fuelling.
Quickest way to to check without any apps or diagnostics connected is to start up from cold (overnight) and feel the top hose from rad to engine as it should remain a lot "cooler than the bottom hose" if it's getting warm after a couple or 3 min it's more than likely stuck open or partially open.

Welcome anybody's views on this post just in case I'm wrong....oh and there is a thanks button if I'm right...............

V70Zig's is the same car as my Dad's, just his has the Polestar upgrade to 205 bhp.

@V70Zig - Thank you for the pictures. It looks simple enough!

[apersson850]

For these models, there were 5-cylinder diesels with 2.0 and 2.4 liter capacity.
Power ranges from 163 to 230 hp.
Today, there are four cylinder diesels badged with D4 as well as D5. The newest are badged B5 or B4, but that's regardless of whether they are petrol or diesel engines.

[lotuscorty]

Just to update guys, I haven't got around to getting the stat changed yet. On my car it is not the same as pictured earlier, it is a complete housing fitted at the rear of the engine, and looks a reasonable amount of work to change, as well as costing around £120. I am working on the theory mentioned that it is stuck open, therefore running cool and overfueling ( i hope). Due to the situation in the country at the moment I may not get around to it for a while, but I will post when completed.
Be safe everyone.

[Bulleidboy]

I've only just read this thread - my 2010 (60 plate) XC70 D5 205 averages mid thirties to the gallon - mainly around town, a little better on a run, but they are few and far between - tyre pressures are 41psi all round on Nexen's.

[Tatsfield]

tyre pressures are 41psi all round

That seems high, is it within the recommended range?

[Bulleidboy]

I'll have to check, but I'm almost sure that I read it on this forum in the first instance?

[37 RUBY]

Originally Posted by Tatsfield

That seems high, is it within the recommended range?

It's the high speed/heavy load pressure. Same pressure on the car in your signature.

I always find 41psi to be a tad harsh when driving solo and dropping to the comfort pressure whilst very nice indeed, it introduces more understeer. So 38 psi for alleged better economy is where I'm at.
I get 34mpg to work and back. I don't see that as too bad for a heavy car.

[lotuscorty]

Ok, so quick update. New thermostat now fitted, tyres all round are at 38psi. Obviously can't go for a run anywhere, but there seems to be no improvement in mpg for the short run to the shops🙄 maybe once I can get out and about to get the average up, it might improve, but at this rate, this will be the last old Volvo I will have.
My old xc90, as underpowered and heavy as it was, was still more economical than the more "modern" xc70, maybe just have to find a suitable v90🤔

[lotuscorty]

Sorry, forgot to mention. Car does now heat up as it should, and reach temperature, so "problem" sorted by the change, just doesn't seem to have had the desired effect on the fuel economy.