A subterranean rumble. An ominous gargle of pipework. A thunderous wall of sound. All sure signs that Mrs Shed has just finished her tea and it’s time to retreat to a safe distance.

More pleasantly these are also the sonic characteristics of a beefy V8, and that’s what we’ve got here under the bonnet of this Jaguar S-Type. The AJ-V8 was one of the default engines for the first X200 Jaguar S-Type. In phase 1 (1999-2002) 4.0-litre flavour it delivered 281hp, 288lb ft and a 0-62mph time of 7.1 seconds. Three years later the AJ’s stroke was increased, lifting capacity up to 4.2 litres. That hoisted the V8’s stats to 300hp and 310lb ft and lowered the 0-62mph time to 6.5 seconds. For the supercharged R version of the new-for-’02 4.2, the numbers were 390hp, 399lb ft and 5.6sec.

Blown S-Type Rs are actually a lot more common on the used market than the naturally aspirated 4.2s, but phase 1 4.0s are on another level of rarity. When Shed was pounding out his dribble for this week, this car was the only 4.0 that he could find for sale anywhere in the UK. Used 4.0-litre engines are relatively easy to buy for between £650 and £800 (minus transmission) because the metal parts that surrounded them when they were new didn’t believe in hanging around, terminal rot rampaging through the sills. Shed saw it coming. Ford bought Jaguar in 1999 but the corporate cheapskate influence had already wormed its way into the fabric of Jaguar by then.

As a keen two-wheeler Shed knew that British motorcycle manufacturers like Norton had used the frame as the oil tank. He wrote to Jaguar suggesting that they make the AJ-V8 a dry sumper, turning the S-Type’s sills into box-section oil tanks. He threw in a pioneering knock-on idea for an oil-powered seat heating system which worked by running a large connecting drainpipe across the floor of the car just behind the B-pillar (and under the carpet, obvs). Besides warming passengers’ posteriors Shed’s oil-filled sills wouldn’t have dissolved into dust and Jaguar would also have avoided the later AJ-V8 issue of leaky sump gaskets. 

Shed received no reply to his letter, or to the other one he sent warning Jaguar that Nikasil bore coating was not a sensible alternative to conventional iron cylinder liners. Their failure to reply could have been down to the absence of stamps on either of Shed’s letters, this being long before the postmistress was franking his mail for free, but he doubts they would have paid any attention anyway. Not that he’s bitter about it.

Sure enough, pre-2000 AJ-V8s did suffer from failure of the nickel-silicon carbide coating but there is no indication of any problems on that score here. The problem was spotted early doors and 2000MY cars (hopefully including this Jan 2000-registered specimen) were put straight back onto iron liners. The AJ is basically a strong engine but this far down the line you’d be well advised to take a close squint at the condition of the coolant because hose and head gasket failure are far from unknown. The uneven cam phasing on the 4.0 that caused irregular loads on the simplex timing chain and premature death of the tensioners was binned on the ’02-on Morse-chained 4.2s. Oil starvation that could kill off the 4.0’s big end was also put right on the 4.2.

All this is making our Shed look about as tempting as a poo sandwich, but the MOT history is actually quite heartening with no real nasties anywhere. Last November’s test was a clean pass. There were some corrosion advisories in October 2020 but these were evidently sorted in 2021 as there’s been no mention of it since. The rest is mainly normal wear and tear to suspension components and some dodgy headlamp aiming. Talking of which, if you believe that all S-Type owners are personal mates of Nigel Farage you will be pleased to note that the leaper on this one is leaning slightly to the right. 

There’s no getting away from the fact that energy costs are front and centre in most folks’ minds these days, so you’ll want to know the official combined fuel consumption figure. Or maybe you won’t. because for the 4.0 it was 23mpg. The good news is that it wasn’t much better on the improved 4.2 at 24mpg, while the ’02 R was even worse at 22mpg. See? Every unburnt hydrocarbon cloud has a silver, and hopefully not Nikasil, lining.