You will feel like the chairman of the board with this Mercedes super coupé
These cars were in production from 1981-91, proving that there is little wrong with the design, luxury or longevity of the model. You’ll appreciate the SEC’s bias toward luxury and refinement and revel in the myriad details designed to make the driver’s life easier.
And when we say luxury, take note; driving an SEC is about as relaxing as they come. Performance is more than adequate by anyone’s standards, especially given today’s speed-limited road environment. Suspension settings are biased toward comfort, with no real-world limit on handling prowess.
Comfort and space are both superb, even in the back, and and even if you’re tall. And if you want to drive a car that shows taste, wealth and style, this C126 will fulfill every 1980s fantasy you can imagine. Just don’t buy a bad one and turn what can be among the best dreams imaginable into a nightmare.
VITAL STATISTICS
MERCEDES 500SEC 1981-85
Engine 4973cc/V8/OHC
Power (bhp@rpm) 245bhp@4750rpm
Torque (lb ft@rpm) 286lb ft@3750rpm
Top speed 140mph
0-60mph 7.9sec
Consumption 17.5mpg
WHAT TO LOOK FOR
BODYWORK & CHASSIS
All panels are C126-specific; no saloon skins here. Wheel trims and alloy wheels are carried over – and the style of the car is similar to the four-door variants. Ribbed rear lights were designed to discourage the accumulation of dirt, and shields ahead of the door handles helped stop them from leaving filthy deposits. The A-pillars were braced to the bulkhead by steel rods which ensured the car was solid enough to forego B-posts, as with every Mercedes coupé since the 1960s. The rear screen seal is a weak spot, causing rotten bulkheads by virtue of leaks – open the boot and look up under the back window. While there, check the condition of the rear screen itself. Replacements are available, but at a price. Rear arches and sills rot, so check for filler and fresh paint. The underseal can come away from corroding floorpans, accelerating corrosion beneath.
The bonnet, boot and rear bulkhead are made from aluminium skins wrapped over steel support frames. It is important to make sure there is no electrolytic corrosion present at the panel edges.
ENGINE
Powered by a 5.0-litre variant of the Mercedes M117 V8, the 500SEC is clearly a potent machine. Fortunately, it’s also the most common. It is easy to maintain, reliable, and diagnosis of any issues is relatively straightforward. Spares are available from Mercedes-Benz, but don’t come cheap. If you’re running a C126 on a budget, we advise you find a Mercedes specialist. If the car has its original plastic radiator, chemicals used in some coolants can damage it – the upper hose neck can fail. Servicing should be done at 12,000‑mile intervals.
ELECTRICS
C126s are packed full of toys – make sure they all work; the more broken gadgets, the costlier the car will be to put back to how it should be. Dashboards are shared with the W126 saloons, though the rev counter replaced the analogue clock in saloon models (a digital clock should sit in the centre of the speedo). The electric seats are unique too, with the fronts featuring a pneumatic locking system to hold the squab up while the car is in motion.
RUNNING GEAR
Gearboxes tend to be durable. Most cars are fitted with four-speed automatic transmission. Ensure transmission fluid is the correct red colour, there are no leaks and that there is no transmission slip or strange noises.
BRAKES
Although SECs never got hydro-pneumatic suspension, the swinging-caliper brakes are unique to the car, but most other mechanical parts are shared with the rest of the W126 range. This means they’re both tough and easy to source. While the steering ratio was altered to give a more engaging feel, steering components are interchangeable.
INTERIOR
There’s not much wood inside, but there’s plenty of leather – check for nicks, tears, or other damage. Re-trims are not cheap. Many came with velour, which is less desirable but tougher.
OUR VERDICT
These Mercedes represent astonishing value for the luxury and build quality they offer. They’re still at the bottom of their value curve, with some potential buyers put off by the cost of fuelling these beasts, and others unable to find examples in good enough condition to campaign as classics.
Customers for new SECs would have included company directors, football managers and millionaires who were after something a little more subtle than the usual Rolls-Royce, but these days they’re seriously cheap. V8 engines have cachet, with the 500 and 560 models only one rung shy of the supercar elite, thanks to its speed and power. Buy one and it feels like you’re treating yourself. Being an old Merc, the sense of solidity is ever-apparent – you feel indestructible in one of these old barges. People say Mercs are competent but bland, but this large, two‑door coupé seems to confound this view. Does it have soul? Your decision. What is for certain, is that it’s one of the bargains of the century.
From the satisfying thunk of the door, to the thoughtful detailing, and quality of the trim and bodywork, you’ll love the SEC. Should you decide to buy one, you’ll probably find it more comfortable, reliable and spacious than your daily driver. Could it be all the car you’ll ever need? The classless lines and the fresh design – conforming to Mercedes ideals of creating shapes that are timeless and stylish while never conforming to the latest fashion – lift the SEC above the humdrum.
A real plus point for this car is the build-quality. Durability is its middle name, while it delivers great comfort for any long-distance journey planned. The only difficulty it seems you’ll have is finding one of low enough mileage to warrant buying, and then refraining from adding to its total.
AUTOMATIC 
RHD
