The Jaguar S-type was launched in 1963 and was based on the styling of the Jaguar Mk2, which had been launched four years earlier. At first glance there is little to tell the two apart, but an expert eye will be drawn to the extended rear bodywork, thinner chrome bumpers and larger indicators. Though a different model, the S-type was essentially an updated version of the Mk2 that featured numerous improvements first seen in the Jaguar MkX. The S-type would fill a niche for consumers who wanted all the technological improvements that came with the larger MkX, but in a smaller package similar to the Mk2.
Among the technological improvements on offer was the independent rear suspension system that was first seen on the MkX, which offered far superior road holding to the live rear axle system used in the Mk2. Though the suspension had changed, the engines stayed the same as in the Mk2 and XK models that came before. Both 3.4-litre and 3.8-litre options were available, but extra weight meant that the performance figures were slightly worse than in the Mk2. Despite the on-paper figures, the S-type was hailed as being a much more capable car, particularly in adverse weather conditions.
The first and most significant wave of developments came only a year after the S-type entered production, in 1964. In line with changing technology, the crossply tyres were changed for radials, which gave the S-type even great roadholding, allowing spirited drivers to better exploit the advanced suspension setup. Also of huge importance was the scrapping of the controversial Moss gearbox, which lacked synchromesh on first gear and had a reputation for being very difficult to use. In its place was a Jaguar unit with synchromesh on all four gears, a unit that proved much more user friendly. An effective Laycock overdrive unit was also introduced.
While early cars are very desirable, the pick of the bunch is cars produced between 1964 and 1966. They benefit from the addition of the more usable and durable gearbox, and also have leather upholstery – which was changed to a cheaper vinyl late in the production run, from 1967 onwards. Luckily, these cars are also the most numerous, with the lion’s share of cars being built in 1965.
Despite the fact that the Jaguar S-type is widely regarded as the better car, values have always trailed behind the Mk2. While the car sold well in period and the technological improvements were well received, the love-it or hate-it styling did not age well. As a result, the S-type presents a fantastic way to get into a real classic Jaguar without breaking the bank.
Incredibly, prices for this wondrous saloon start from less than £10,000, topping out at around £25-30,000.
If you’ve got your heart set on a Jaguar Mk2 we would suggest you go for a quick spin in a S-type before you make up your mind. The improved mechanicals give the S-type much-improved handling – as long as you can get along with that big back end. Values are sure to rise.

VITAL STATISTICS
ENGINE 3781cc/6-cyl/DOHC
POWER 220bhp@5500rpm
TORQUE 240lb ft@3000rpm
TOP SPEED 121mph
0-60MPH 8.5secs
ECONOMY 22mpg
GEARBOX 4-speed manual

WHAT TO LOOK FOR
BODYWORK
Unsurprisingly, weakened bodyshells are the cause of most S-types being scrapped. The Mk1 (which evolved into the Mk2 then the S-type) was Jaguar’s first monocoque model, so its structure incorporates numerous rust traps – it doesn’t help that Jaguar applied virtually no rust prevention measures. Take on a baggy S-type and you’ll need lots of expertise – plus a well-equipped workshop – to revive it. Get it revived professionally and it’ll cost you far more (potentially £30,000+) than to just buy a decent example at the outset.
If there’s much visible corrosion, there’ll be lots more hidden, in the structure – an S-type that looks superficially good can be rotten underneath, so get the car on a ramp. Start with the two longitudinal chassis legs, which meet a crossmember beneath the nose. Although the structure is unitary, this integral chassis adds essential strength. Also focus on the area where the chassis legs join the crossmember and the adjacent crows’ feet, which tie the front wings to the crossmember. These are the supports for the front wings, along with the vertical radiator cowls. Expect rust here, allowing water into the chassis leg.
Corrosion then moves down to the jacking point below the A-post, so look for distortion of the metal and poor-quality plating. This area is often bodged, as it’s complicated.  Check the base of each front wing, looking for cracking paint working downwards across the sill from the bottom front corner of the door aperture. This area is key, as proper restoration requires a jig for strengthening, and all rotten metal cut out.
The usual giveaway is uneven door shuts, the lower front corner sticking out while the window surround is in contact with the door jamb. Other rot spots include the rear anti-roll bar mountings, floorpans, wheelarches and the back of the sills along with the spare wheel well’s centre section and the fuel tanks (there are two). That’s not all, though; the outer panels also corrode spectacularly, especially the grille and headlight surrounds plus the area where the sill and front door meet along with the rear door/wheel spat junction. The trailing edge of the bootlid rusts, as do the door bottoms.

ENGINE
Offered in 3.4 or 3.8-litre forms (S-Type) or 4.2-litre (420), the XK engine needs regular maintenance if it isn’t to wear prematurely. Look for a service history, make sure the engine doesn’t sound hollow or rattly and ensure the oil is clean. Budget for a rebuild as soon as the engine shows signs of wear; delay things and the bills will quickly mount, especially if something breaks.
The XK powerplant features a cast-iron block and alloy cylinder head; because of the latter, anti-freeze levels must be maintained or internal corrosion is guaranteed. Even a well-maintained engine could need a fresh radiator every five to ten years; new ones are £500 exchange, with alloy versions available for much the same money. To check for engine wear, take a look at what oil pressure there is; a healthy unit will show 40psi at 2500rpm.
However, senders and gauges tend to under-read, so use a temporary gauge for an accurate picture. Some oil consumption is normal, but lots of smoke on the over-run or when the throttle is blipped means hardened valve stem seals or worn valve guides. Specialists charge £1500+ to fix things, but complications such as corrosion of the water ports could mean a significantly bigger bill. XK engines can be made oil-tight, but a bit of weeping is normal. However, if the car’s underside is coated in oil it’s probably because the rear crankshaft oil seal has failed, signalling it’s time for a complete rebuild. Specialists charge £4500+ or you could do the work yourself for £800+, but it requires a special tool plus knowledge to fit the oil seal.

TRANSMISSION
Until September 1965, manual-gearbox S-types had a four-speed Moss transmission without synchromesh on first. It’s a strong unit, but on hard-driven, abused or high-mileage cars you should expect some wear.
Parts for this gearbox are hard to find, so rebuilds are costly. Later S-types and all 420s came with an all-synchro box that’s also strong, but much harder to find on a used basis, so whatever is fitted, make sure it doesn’t jump out of gear and that you can select ratios easily.
Overdrive was optional for all S-type and 420 derivatives, but most cars came with it. A Laycock system, expect it to engage smoothly and swiftly; any issues are likely to be down to clogged filters or dodgy electrical connections. Rebuilt overdrives are available for around £350 on an exchange basis. A new clutch means removing the engine, and a three-piece kit is £200 or so. Most S-types and 420s have a Borg Warner automatic. A DG unit was fitted until June 1965; after that there was a Type 35 unit. Both are durable, but the latter is smoother. Rebuilds are rarely needed. Graham Whitehouse charges £2675 to overhaul the lot (including the torque converter) and another £860 to remove and refit everything. You can expect to pay anything from £250 for a usable second-hand auto box; the DG and Type 35 units are interchangeable.
Whitehouse also offers a conversion to a modern four-speed auto, but it’s complicated as it requires a new propshaft, drive plate, starter motor and more. For the parts alone it costs £6200; get the Whitehouse team to do all the work and you’ll have to cough up another £2800 if the car starts out as an auto. Convert from a manual and labour becomes £5000.

STEERING & SUSPENSION
Neither the S-type nor the 420 got power steering as standard, although it was a popular option – and something that’s necessary with the weight of that big straight-six in the nose. Earlier power steering featured a Burman recirculating ball system, which is low-geared, but reliable. Later, there was a higher ratio Adwest power steering system, giving a much better feel. One of the key characteristics that separated the S-type from the Mk2 was the fitment of independent suspension all round; it’s the same set-up as fitted to the Mk X and E-type models.
As such, it’s reliable but you still need to check for the usual potential issues such as tired dampers, worn bushes and sagging springs; everything is available and upgrades are easy.

WHEELS & BRAKES
Wire wheels are a popular fitment; if fitted, make sure the splines aren’t worn by getting somebody to sit on the car with their foot on the brake. Try to rock the car top and bottom; any detectable movement indicates worn splines. Also look for rusty or broken spokes; replacement 72-spoke wheels are £250 apiece (chrome) or £150 for painted items.
As with the Mk2, the S-type and 420 came with disc brakes all round, but even in good condition the system is only just up to the job, while the 420 benefited from having different front uprights and larger three-pot calipers. The problem is usually down to corroded pistons and cylinders. Everything is available and upgrades are straightforward, but parts costs are high although the system is relatively uncomplicated.

TRIM & ELECTRICS
A 1960s Jag interior is something to behold if in good nick. However, Jaguar didn’t use the best quality materials, so tired trim is common. You can buy some superb quality trim kits to make it all as good as new, but by the time you’ve replaced the carpets, seat covers, trim panels and headlining you could easily spend £4000 for the parts alone; get it all done by a specialist and that could add another £2000-£3000 to the bill.

OUR VERDICT
You don’t have to be on a budget to fancy an S-type or 420 over a Mk2, as these overlooked models are superior in ious ways. However, if buying a Mk2 is fraught with danger, trying to find a decent S-type or 420 is even more so, as decent examples are rare. Good survivors of either type aren’t common, which is why you absolutely must buy the best you can afford and the best you can find.