Remember that UK gallons are 20% bigger than USA gallons so 25mpg to us yanks is 30mpg in the UK.

My XJS V12 could manage 22 mpg on the highway...USA gallons, that is...if I took it easy. If I was givin' her the boot quite often it was more like 18-19 mpg. City driving was 12-13 mpg.

Driven gently I think 25mpg highway should be doable with a 6-cylinder XJS. Heck, I can get 23 mpg highway with my XJR if I stay below 70

Cheers
DD

 

Well Doug you live and learn ! I didn't even know there was a difference ! Why is life soooooooooooo complicated ?
The original UK government test figure for the 4.0 L coupe in UK gallons was as follows.
Urban 19.8 ( US 24.02 )
Steady at 56 MPH 35.8 ( US 42.96 )
Steady at 75 MPH 28.5 ( US 34.20 )

So Vee, I would imagine your convertible is not as aerodynamic as a coupe even with the the top up so your car would appear to be performing correctly.

 

USA gallons are *smaller*, so.....

19.8 UK = 16.5 USA
35.8 UK = 29.8 USA
28.5 UK = 23.8 USA

Cheers
DD

 

Yes well done Doug, I was aware of the difference but had forgotten until you mentioned it.

For what it's worth my UK 4.0 facelift coupe auto returns pretty much the figures you suggest Richkaz.

Urban if I'm gentle = 19-20mpg.

Urban if I'm aggressive = 16mpg.

Motorway cruising @70mph = 27mpg on average or 30mpg over a long distance of say a couple of 100 miles.

Matt

 

Thanks for that correction Doug. It would seem that the 6 cylinder cars on this post are pretty well doing what they say on the tin.
One thing I do need to clear up
Those Texan 10 gallon hats. Are they English or American gallons ?

 

I never owned an XJS, but I did have a 1980 Series 3 XJ saloon, and met a few owners of the XJS cars. The XJS was a very low production car, sometimes only a few thousand were made in a whole year. It relied heavily on the XJ saloon for mechanical parts, and that is a big advantage, because there are loads and loads of parts and eager suppliers out there. The big disadvantage was always the body shell, even worse protected than the saloons and that was pretty poor, I can tell you, with my personal experience of the saloon. Ford did improve the car a lot in the early 90s with the restyle. However old or new style, these cars can and usually do rust badly if exposed to cold and damp conditions and especially salty roads.

My advice, therefore is to try to find one from a southern state, preferably from a retiree in Florida who has not really used the car, just pootled around in it. That way you should get a good bodyshell.

Despite all this, it will still be an old car, and suffer some faults, so you must be able to acquire that famous Jaguar fortitude and endurance when problems come up.

Of course you always have the choice of buying an XK which is much better made, but much more complex and more difficult for owner/maintainers, although I believe there are still some common parts with the XJS, maybe experts can confirm. If you have a good local Jaguar specialist, and the money, this might be a better choice.