It has long stayed under the radar, even though it’s a Mercedes roadster – the 190SL has never been high on most car collectors’ lists.

That’s because, with ‘only’ a 1.9-litre four-cylinder engine to propel what is quite a heavy model, the 190SL has traditionally been regarded as underpowered; more of a poser’s car than an enthusiast’s machine. Truth is, however, that a 190 is actually a very satisfying drive. 

Build quality is impeccable and the monocoque construction helps give it that hewn-from-granite feel that is conspicuously lacking from British cars of the period. And how many people these days drive their 1950s classics flat-out, anyway?

Although it’s no rocket ship, the 190SL has more than enough performance to keep up with modern traffic, and the steering and gearchange are lovely to handle. The twin-carb, four-cylinder engine was designed to run on low-quality post-war petrol and will typically return 25mpg on regular unleaded.

When new, the 190SL was sold as a roadster or with a detachable hardtop. As the panel (right) shows, changes were few in its nine-year run, so condition rather than specification is your main concern when buying.

Father and son team Brian and Simon Gunney (above) are the entire staff of Redcastle Classics, a South Wales-based restoration firm that has been specialising in 190SLs for the last 20 years – although Brian has worked on them since 1970.

‘The 190 has always been largely immune from market fluctuations,’ says Brian. ‘It tends to sit at roughly the same price level, whatever’s going on in the wider world. But now that the 300SL and SLR are fetching huge money, the 190 has inevitably hitched a ride on their coat-tails. 

‘In the UK, a well-restored and fully sorted car is worth about £50,000, although in Europe that rises to £80,000. At the bottom end of the scale, basket-case project cars start at £7000, with better projects fetching up to £15,000. 

‘The factory hardtop might seem a desirable option but it’s very heavy and not many people use a 190 in winter, so it adds little if any value.’

IT’S A 1950s car, so no prizes for guessing that rust, rust and rust are the top three priorities on your check-list when looking at a 190SL.

The 190 has a steel monocoque with a cruciform stiffener underneath. Outer wings are steel, too, but bonnet, doors and bootlid are made of aluminium. The latter usually suffer only surface corrosion but the rest of the body needs detailed inspection; a sound shell could save you £10-12k from the cost of a restoration.

Because it’s a Mercedes, many parts can still be obtained through MB’s heritage scheme (Jacksons of Bournemouth in the UK), but they will often be hugely expensive. Apparently trivial items can have eye-watering prices – a pair of wiper arms/blades is £400, while a front grille (shared with the 300SL) is £3500. Plus VAT.

However, there is a growing market in repro parts. Some are good quality, some aren’t – US-made interior retrim kits, for instance, don’t always fit well, so a bespoke retrim is a popular option, generally done these days in leather rather than the period-correct MB Tex vinyl. 

Mechanically, the cars are strong. Parts supply for the engine – unique to the 190SL, although the bottom end is similar to the 190 Ponton saloon’s – is very good from Mercedes, and the Solex carbs can be rebuilt to be more reliable than they were when new. Seal kits for the ATE brake booster aren’t easy to source (though Redcastle can do it); it’s not unknown for a different servo to have been plumbed in.

The 190SL had quite small 13in wheels and tyre choice is limited: Michelin X radials are by far the best and will retain the original rolling radius. That’s important because overdrive was not an option, so you don’t want to reduce the gearing further by fitting lower-profile rubber.

They’re not cheap cars in any sense of the word, but a 190SL is well worth considering if you are looking for a long-term commitment. Its inherent quality means it will probably outlive you, and it can only increase in value.

As always, an untouched original example represents the ideal, but there are very, very few such models left. Whether a car is original or restored, tight-fitting panel shutlines are a reliable instant indicator of the general quality, but inspection by a specialist is always a wise investment – Brian Gunney will travel to check out a potential buy, if requested.

The 190 may not have the macho appeal of a Healey or Triumph TR, which are still the default option for many people who want a two-seater roadster, but it’s in a different league for quality; a good one will also be quite inexpensive to run. It’s a more imaginative alternative to its obvious rival, the Porsche 356 – and you won’t have to worry that people are thinking you’re driving a kit car. And the ladies love it…