1979 Mercedes-Benz 450SEL 6.9

This Mercedes sold for $4,239, including buyer’s premium, at Bonhams & Brooks’ Olympia London auction, December 4, 2000.

There is no disputing the glory of the 6.9. This worthy successor to the 300SEL 6.3 was better in just about every capacity. The 6.9’s engine produced 286 DIN horsepower, enough for a saloon by any but supercar standards. The real surprise, though, is the amount of torque-an astonishing 405 ft/lbs-that translates into 0 to 60 times of about 8 seconds, and a substantial appetite for fuel.

There are no hippety-hop swing axles at the rear of the 6.9, as it was blessed with the double-jointed half-shafts of the 450 series. Forsaking the troublesome air-bag suspension of the 300SEL series, Mercedes gave the 6.9 a new, and still-troublesome, hydropneumatic system with spherical pressure reservoirs at each wheel and suspension media of nitrogen gas and hydraulic oil. Citroën mechanics should feel right at home.

To ensure you could make it home from your favorite lakeside retreat, Mercedes-Benz outfitted the trunk with four rubber blocks. If your suspension failed, the owner’s manual instructed you to jack up a corner of the car, remove the wheel, insert the rubber block, wire it into place and remount the wheel. After repeating this for all four corners, it was best to wash down several aspirin with a liter of dark bier and call your dealer in the morning. Then you would need to get in touch with your mortgage broker and refinance your home to pay for the upcoming service.

Before buying any 6.9, invite a few friends to hop into the trunk while the engine is running. Watch to see if the suspension does its job by keeping the ride height constant. If it doesn’t, don’t take the car unless the seller is willing to pay you at least $5,000 to take it off his hands. Asking for $10,000 would be more appropriate, but it’s best not to get greedy.

So why the puny price for such a high-performance machine? Why has this mighty 6.9 fallen so far from grace, bringing money roughly equal to what a 1990 Honda Accord with six figures on the odometer would make?

The simple answer is that the 6.9s are terribly complicated cars, and are expensive to maintain, even well beyond their suspension woes. It’s not because the engines are fragile either; they’re not. It’s the little things that drain the pocketbook: the prodigious torque takes its toll on transmissions; the air-conditioning systems are complex and costly; even the servo for the heating system is notoriously expensive to fix.

Furthermore, if not maintained continuously to the highest standards, these cars age poorly. The superb finish on the wood loses its gloss, the horse-hair padding in the seats goes flat, and rust creeps into the trunk and lower rear quarters. To duplicate the superb quality of the original paint takes a minimum of $5,000 and, with some bad luck, can easily be twice that.

So, if you find a 6.9 that has needs, realize that your acquisition is just the first, very tiny step on the road to fiscal self-immolation. Like many complex exotic cars, from Lamborghini Espadas to Porsche 928s, the 6.9 on the best day of its life struggles to breach the $15,000 barrier. Worse, when all is said and done, you’ve got a car with too many doors and too many seats to ever be collectible.

This king-sized car was a minor bargain so long as it runs and drives to spec. I was once told of a man who would buy a 6.9 every couple of years, drive it until something big and expensive (or small and expensive) broke, junk the car and go buy another one. That sounds like a prudent plan to me.-Jim Schrager

(Photo and data courtesy of the auction company.)