Currently reading: Used car buying guide: Mercedes-Benz SL320
R129-gen cruiser is a no-brainer if you’re after a prestigious and solidly built used convertible, but there are pitfalls to be avoided
John Evans
News
5 mins read
14 October 2019

Sand L: two letters that tell the world you’ve made it. There have been seven generations of the Mercedes-Benz convertible, each more or less as impressive as the other, but it’s the R129 generation under the spotlight here. The model was in production for a full 12 years from 1989 to 2001, and for drivers of a certain age, it sticks in the memory. 

Why? Bruno Sacco’s styling for a start, and then there were the engines, the advanced technology and the sheer driving experience that together propelled this legendary car into the modern age. 

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It was a strong seller, with the result that, today, there are a fair number on the market at prices ranging from £3000 for a high-mileage 1997 P-reg SL320 to as much as £40,000 for a 1995 N-reg SL500 with 10,000 miles on the clock. In between is a riot of 280s, 320s and 500s at all ages and mileages, and in all conditions. There’s little rhyme or reason to the pricing so if you’re tempted to buy one, you should look at and try as many as you can. 

Increasingly, sellers describe the model as a ‘classic’, and one with a low mileage, no faults and in top condition may very well increase in value. However, experts we spoke to warn that rust is now rearing its head – the kind of rust you can’t see without lifting carpets. 

It was launched in 1989 with an automatic gearbox, gas-filled dampers, a removable hard top, a pop-up rollover bar and kit taken from the S-Class. It’s a heavy thing but the model’s new engines ensured it had sufficient muscle. Depending on the model year, they were a choice of 2.8, 3.0 and 3.2-litre straight sixes producing between 193bhp and 231bhp, the latter in 24-valve, twin-cam form. Then there was a 326bhp 5.0-litre V8 and a mighty 394bhp 6.0-litre V12 (we found a 1999/T-reg SL600 with 74,000 miles and full service history for £21,950). There was also an AMG version with a 6.0-litre engine but this time a lighter V8, producing 381bhp. 

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Of them all, our pick is the dependable 231bhp SL320, a facelifted model from 1996. That said, one to watch is the SL600. The V12 is whisper quiet, although access to it for even minor repairs (the throttle bodies can be troublesome and it can suffer internal corrosion) is difficult and, as such, very expensive. 

Major milestones in the SL’s life were the move away from the two-tone paint scheme, plus restyled bumpers and the adoption of brake assist in 1996. Then in 1999 the instrument cluster gained chrome rings and the steering wheel a big Mercedes star in its centre. One good option to look out for is folding mirrors, so you can squeeze your SL into the garage more easily. 

The SL signed off with the SL500 Silver Arrow special edition complete with autographed Stirling Moss portrait. Only 100 were produced. We found a 2001-reg example with 21,000 miles for £43,995. Now that’s one SL that really says you’ve made it.

An owner’s view 

Gordon Bishop: “I bought my 320 in 2000. It was a few months old with about 1500 miles and had been a dealer demonstrator. It’s since racked up almost 120,000 miles and has never failed me. SLs like to be driven; they hate standing around. Despite the mileage, it’s in beautiful condition. The paint is tough and the alloys haven’t corroded like they can on lesser cars. It’s everything I could want in a car: attractive, comfortable, well equipped and built like a tank. It’s always serviced on the button, mostly specialists using Mercedes-trained technicians. I’ve still got the hard top. Luckily, I have the space to store it.” 

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Buyer beware 

■ Engine: Experts call it a ‘biodegradable’ wiring loom for the way it disintegrates over time. Misfires are often traced to it. A replacement loom costs from £150 but labour is much more. Water ingress is usually the cause. Leaky head gaskets on early six-cylinder cars and throttle body wiring issues on V8s are also a problem. A rattle at tickover could be the catalytic converter breaking up. 

■ Transmission: Gearboxes are generally reliable, the four-speed more than the later five, which can suffer oil contamination. Regular filter changes prevent it, so check they’ve happened. 

■ Suspension and brakes: The SL is a heavy car so expect front lower ball joints, top mounts, bushes and springs to show some strain. Check for overworked discs and pads. 

■ Electrics: Check the battery is holding its charge. If it’s failing, it can trigger warning lights. Old alarms are known to be a power drain. 

■ Body: Specialists are seeing more rusty SLs these days, problem areas being the boot floor and leading edge of the front wings. Check that the powered hood works, because if left unused for some time, the electronic module packs up. On that point, be wary of a car with its hard-top fitted.

Interior: Aside from checking the leather is in good condition and that the powered seats do their thing, make sure all the electrical features work. On the test drive, be sure the air-con chills the cabin and that the heater warms it up.

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Also worth knowing 

How do you remove and store the SL’s 40kg hard top? Motorform-shop.de sells a hoist that allows you to remove the roof from the car on your own. Some owners rig up a pulley system and suspend it from their garage rafters. Alternatively, the SL Shop can supply a heavy-duty storage stand. 

How much to spend 

£3500-£6999: Mixed bag of 280s, 300s, 320s and 500s, pre- and post-1996 facelift with high mileages. 

£7000-£10,999: Conditions improving from this point with mileages closer to 80,000, but you’re still in perilous territory. 

£11,000-£14,999: Mileages edging towards 30,000 and some nice 280s and 320s in good condition, with full service history. 

£15,000-£19,999: You should find very nice late-plate 320s for around £19,000. 

£20,000-£25,000: The best late-plate 320s, and expect to find the best 500s with panoramic sunroof at around £25,000.

One we found 

Mercedes SL320, 1997/P, 93,000 miles, £5995: A nice facelifted SL320 with full history (a mix of main dealer and specialists; check the invoices for details of work done) and with hard and soft tops. And no rust, claims the seller. 

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si73 14 October 2019

I prefer it's looks with the

I prefer it's looks with the hard top on, looks like a GT coupe.