Used Volvo's - Best Gas Mileage?

I've got a 91 Volvo that has served me well. Bought it used in 97. I'm
looking at possibly getting another one whenever this one bites the dust
(could be another 10 years). Which ones have the best gas mileage?

I'd like a wagon again too.

 

The 850 series generally gets decent mileage, any of the 4 cylinder ones are
ok, and the 6 cylinder Volvos tend to be a bit thirsty. Fuel economy is not
a Volvos strongest point, but they tend to do well for what they are.

 

I can get 26 out of my 91 740 wagon, if I keep my foot out of it, and
the tires over-inflated. I'd like something in the 30's.

 

6 cylinder diesel gets excellent milage but is an aging engine by now.
4 cylinder gas is very reliable and can get close to 30mpg on the
highway.

 

Aside from the little 340/440 hatchbacks in Europe, the best
mileage will be with a 240 or 740 with standard transmission and
overdrive. The 940 may also qualify.

 

It would, except that in North America you can't get a 940 with a standard
transmission.

I thought the 850s got slightly better mileage? Somewhere I heard 31-32,
which I've gotten out of both a 240 and a 740, but it took some doing.

 

The non-turbo 850 5-speed might get in that range. The automatic
versions are no better than the 240, and probably worse. I'm pretty sure
I've seen 940s advertised with 5 speeds, but maybe it was a misprint, or
a Canadian import...

 

The 5 speed 940 had the M90 transmission, they weren't sold in Canada
either, Europe only. A few people have imported that gearbox, as well as it
should be possible to convert a 940 using an M46 or 47 with parts from a
740, but none came that way. Aside from some minor cosmetic changes, a 740
and 940 are the same car.