1986 Mercedes-Benz 420 SEC

This 420 SEC was first registered new in the UK, but is now on Irish plates after an enthusiast there bought it around five years ago. The Irish version of the UK’s MoT is the National Car Test (NCT) and this car has passed this test. To quote the vendor: "I always wanted an 420 SEC – a great big body car and a most reliable friend. It has never let me down and is a much loved beauty. The car is a classic head turner and will be a wonderful car for the new owner."

The car has an excellent service history and a very low mileage of just 82,000. The build quality of this period of Mercedes is absolutely unparalleled by any other make of car, and indeed by modern Stuttgart products, which have sadly become the subject of accountants’ cost cutting measures.

When this car was built Mercedes engineers dictated how a car was built, and the result is a vehicle that will easily cover a quarter of a million miles without needing any major work (I know, as my own 1987 500 SEC has just passed the 250,000 mile mark, and still runs like a Swiss watch).

The W126’s replacement was the W140 and was again the work of Mercedes chief designer, Italian Bruno Sacco. The later car is another fine machine, but Sacco was unhappy with the coupé’s roofline, which he considered too high.

Black paintwork reveals any problems underneath like no other colour, but we’re happy to report that the finish on this coupé looks excellent. The paint shines with a deep lustre, the shutlines are all tight and even, and panels all straight and true.

It’s not perfect – we spotted a tiny mark on the very tip of the alloy bonnet panels and a slight paint defect on one corner of it, but overall the car’s exterior condition very much reflects its very low mileage.

The original spec Mercedes alloy wheels are all in excellent shape with no kerbing marks we could see, and all are shod with good tyres. The car’s brightwork is also in great condition, with no lacquer lifting.

The front fog lamps are mounted low and in an exposed position, but show no signs of damage. The sunroof panel appears rust free and undamaged.

The plastic covers on the headlamp washers can crumble on these cars, but on this one they’re in fine condition. The plastic panels covering the lower sections of the bodywork are all straight and have excellent paint.

Both the front and rear screens can delaminate on Mercedes of this period but again, no such problems exist here. At the rear, because of the steep rake of the screen, the rear seal can leak and this leads to the panel below it rusting, but this looks undamaged. 

The military spec build quality continues inside this top of the range coupé, and at this kind of mileage we’re not surprised at all to see it looking in beautiful condition. 

The electrically adjustable cream leather front seats are in superb shape, with only the very smallest hints of use on the driver’s seat bolsters and the central armrest. The rear seats look unused, probably because they are. You can fit full size adults in here but they have been known to complain about a lack of space.

Wooden trim in this model of SEC is highly lacquered and very hard wearing, and generally in tip top shape in this car, although the veneer is lifting slightly on the glovebox panel. However, this could be easily rectified with nothing more costly than a tube of Evo Stick and a spare 10 minutes.

The cards on the exceptionally long SEC doors are unmarked by clumsy feet and each features the controls for adjusting the front seats. The cream carpets are protected by original Mercedes over-mats.

Inside the spacious boot the full size spare wheel sits underneath a wooden panel and is in just as good a condition as the other four alloy wheels, save for some tiny marks on its outer edge.

Earlier versions of the SEC coupé came with a 3.8-litre version of the Mercedes M116 V8 engine, which had a single row timing chain that can stretch and cause problems, but later versions such as this 4.2-litre example have a duplex chain which doesn’t suffer the same problem. 

82,000 miles on a bread and butter 1987 car might be considered relatively high, but on a W126 Mercedes it’s nothing. These engines are all alloy and have no steel cylinder liners, instead relying on a special honing technique to produce a high silicon content bore, which is incredibly hard wearing.

And despite later cars from BMW and Jaguar with Nikasil bores suffering from problems as a result of high sulphur content fuel, the Mercedes M117 V8 never had these problems. 

The single overhead cam per bank V8  - the original unit to the car - is in lovely cosmetic condition on his car, with only very mild surface blemishes on some of the plated components and alloy parts to hint that it might be nearly 40 years old (and hence MoT, road tax and ULEZ exempt in a couple of years).

The engine bay is very original too, with its factory warning stickers still in place.

This low mileage Mercedes SEC coupé comes with a comprehensive service history and its original handbooks. The history file also includes a stack of old MoT and NCT certificates, plus detailed service records with mileages.

The vendor states: "the car was purchased in 2018 from a pal who lived in Windsor, UK. We still have the UK plates. The reason for selling is personal circumstances, otherwise would be hanging onto this beauty. It's maintained and lives in a heated garage in Dublin. It has a very good log of early paperwork, see photos of paperwork.”

Maybe we’re biased, but we think this is peak Mercedes. And he may be biased too, but the car’s designer, Bruno Sacco, obviously agrees, as a C126 SEC is still his daily driver. 

This is a beautiful example of the breed, and remember that in a couple of years’ time it will be immune from ULEZ charges too, making it the kind of classic you can still use in the UK’s cities. We estimate that it will sell for €20,000 - €25,000.

Viewing is strongly encouraged, and this lot is located with the vendor in Dublin, Ireland. Viewings are strictly by appointment. To make a booking, please use the Contact Seller button at the top of the listing. Feel free to ask any questions or make observations in the comments section below, and read our ‘Frequently Asked Questions’.