RE: Mercedes SL 350 (R320) | Shed of the Week
RE: Mercedes SL 350 (R320) | Shed of the Week
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Mercedes SL 350 (R320) | Shed of the Week

Probably the best looking SL of the 21st century is available for shed money - should you take the plunge?


If Shed had a pound for every ‘project’ he’s been offered (and rejected) over the years, he’d have enough money to take the postmistress to the Maldives. This bargain basement ‘project’ R230 SL 350 is different. It’s got him seriously scratching his stubble.

The R230 SL landed in 2002 and remained in Mercedes brochures for more than ten years. Many believed it to be the best-looking SL. Some still believe that. At £2,000, this car is being offered at well below normal retail under the tempting project header. It was registered in 2006, four years into the production run, which was enough time for some of the (many) early issues to have been sorted, but some have come back to haunt it.

Like what? Well, the R230 was Mercedes’s first attempt at a folding metal hardtop and as you might surmise from M-B’s bad reputation for electronickery at this time they weren’t problem-free. Our shed’s roof isn’t working. Specialists Hoodtech list about twenty ways in which it could go wrong and quote an average cost of repair of £495-£595 including VAT, but if you’re very lucky it might just be a dodgy consumer battery, the second one in the SL’s boot that’s responsible for ancillaries including the heated seats and the roof. You should always keep it on a trickle charger to maintain its minty freshness. Like Mrs Shed, it should never be jumped.

Once you’ve got the roof working, cheaply or expensively, it’s worth shoving some Gummi Pflege or Liqui Moly Rubber Care on all the seals. There’ll still be a degree of creaking in the cabin but there should also be less water getting in. Water can get into the boot too, often via a poorly fitted or cracked bootlid light. Rust will certainly attack the wheel arches of neglected R230s, but so far at least there have been no appearances of the ‘c’ word on the MOT history.

All SL 500s had roll-reducing Active Body Control as standard, but Benz’s electronically controlled hydraulic system was only an option on the SL 350. You’ll be hoping that the box wasn’t ticked for our shed because ABC is notorious for failing in a pricey way. There’s no mention of ABC on the ad so we could be all right there.

When the M112 engine appeared in 1997 it was Mercedes’s first petrol-powered V6. A twin-spark, single cam, three valves per cylinder design with a vibe-dousing balance shaft, the M112 came in various capacities from 2.4 litres to the biggest 3.7 (a bored out version of the 3.2) that powers our shed. It’s not the 2006 facelift motor with 268hp, but it’s still healthy enough with 245hp and 258lb ft to generate a raspy 0-60mph time in the low sevens. 

The M112 has proved to be a solid and reliable unit. This one has had an oil leak since 2021, most likely from one or both of the rocker covers. These leaks are easy to put right, but replacing dead hydraulic pumps, hoses and accumulators isn’t the work of a moment. ECU issues can queer up the transmission and the PSE central locking vacuum pump. Our car has non-functioning central locking. Dealers will try to hit you up for £1,000 or so to replace the complete pump, but more often than not it’s just the pump’s graphite impeller that needs replacing. You can pick one of those up off tinternet for under £30.  

The big downside of an older, high-CO2-emitting (276g/km) engine like the M112 is the tax hit it takes in the UK. Our shed was first registered on 31 March 2006. If it had been registered eight days earlier it would have sneaked into the mysterious VED Band K* at £445 a year. As it stands though, the bill will be £790pa - gah. 

Some might add ‘non-functioning roof’ to ‘airbag warning light’ and come to ‘crashed’. Obviously spending a few quid on a history check would be a wise investment, then you’ve got three months’ worth of MOT to get the airbag sorted. If it’s just the module that needs resetting, you could get away with a bill of well under £100. The interior is crying out for some restorative elbow grease on the leather and wood bits, but unless the wheel has got Novichok on the rim that isn’t going to worry the MOT tester so you can tackle that in your own sweet time.

When this car was new it would have cost £63,000, which is £118,000 in today’s money. This shed will cost you £2,000, which is £2,000 in today’s money, or about six PCP rental instalments on a Ford Focus. If you’re ready to take up the vendor’s ‘project’ challenge and you get lucky with the fault fixing, you could end up with a right result here. 


See the original advert

Author
Discussion

tomsugden

Original Poster:

2,458 posts

256 months

Beautiful, I'd happily smoke around in that. The link to the advert is broken though.

https://www.pistonheads.com/buy/listing/20829534

Edited by tomsugden on Friday 7th August 06:10

JRaj

127 posts

101 months

Private plate, job done.

Mini SLRs. Great shape and for it's age still classy.

FrankandLynn

85 posts

21 months

In the same vein as the recent S280, it’s tempting to imagine the fun potential - less so to recognise the reality of days, and large sums, spent tracing and rectifying the myriad of existing problems and those waiting to present themselves. Regretful no.

nismo48

6,805 posts

235 months

Great value shed, some DIY fixes and she's a goddun thumbup

can't remember

1,164 posts

156 months

Mouldy looking seatbelts in a none functioning convertible known for leaking. You never know, you might get lucky.

Mark_Blanchard

1,042 posts

283 months

Wow! Best shed ever, love it.

fozzymandeus

1,092 posts

174 months

Mercedes’ first attempt at a folding hard top?
Erm. No - R170

And the leaks into the boot are not the rear light units, they are the rubber seals at the base of the c pillars - they’re a design flaw that means they get pulled away from the c pillars themselves under the pressure of the closed bootlid.

These hallucinated details on behalf of the article whiff a bit of… “assistance” in the authorship.

Check for rust in the c pillars themselves, too. There’s a spot weld right in the gutter that’s basically been designed to sit under water most of its life. I also bet this has had a boot floor that’s been made into a man made lake at some stage. Trouble with a capital T.

apm142001

293 posts

117 months

The M112 was indeed reliable, but I’ve a feeling that this model year would have been the M272 engine with the known balancer shaft issue. Though I suspect that’s the least of this particular example’s worries.

JD2329

510 posts

196 months

The R170 SLK released in 1996 was the first Mercedes with a folding hard top. The roof mechanism on an R230 is more complex, but normally durable. Failure to operate is often a microswitch which a diagnostic should show up. Keep the seals well lubricated as mentioned and it should be reliable.

This model with the M112 V6 and the five speed auto gearbox is about as bombproof as an SL gets.
Oil leak from rocker cover and breather cover is common and a straightforward job.

350s were not specced with ABC unless ticked as an (expensive) option.
Post 2004 models were galvanised so rust is less of an issue than with earlier examples.

With both the roof not working and the airbag warning light on, there could be a colourful backstory…if there’s an explanation for the airbag light, then this could be an outrageous bargain.

fozzymandeus

1,092 posts

174 months

apm142001 said:
The M112 was indeed reliable, but I ve a feeling that this model year would have been the M272 engine with the known balancer shaft issue. Though I suspect that s the least of this particular example s worries.
No this is an M112; it’s a 3.7 and a pre facelift.

Also I note the fuel filler cap is being held shut with tape, suggesting more central locking maladies - PSE pump and boot aquarium seem likely.

fozzymandeus

1,092 posts

174 months

JD2329 said:
The R170 SLK released in 1996 was the first Mercedes with a folding hard top. The roof mechanism on an R230 is more complex, but normally durable. Failure to operate is often a microswitch which a diagnostic should show up. Keep the seals well lubricated as mentioned and it should be reliable.

This model with the M112 V6 and the five speed auto gearbox is about as bombproof as an SL gets.
Oil leak from rocker cover and breather cover is common and a straightforward job.

350s were not specced with ABC unless ticked as an (expensive) option.
Post 2004 models were galvanised so rust is less of an issue than with earlier examples.

With both the roof not working and the airbag warning light on, there could be a colourful backstory if there s an explanation for the airbag light, then this could be an outrageous bargain.
I think the pre facelift cars had been given the 7G tronic box by 2006, unsure as my 2003 car had the 5G. It’s still happily MOTed today though, on about 150k miles which supports the mechanical robustness claim.

CornedBeef

639 posts

216 months

The other fun complexity with these is the SBC braking system, but would this be too late to have it? My SL500 had both ABC and SBC and they gave me anxiety.

Venisonpie

4,721 posts

110 months

fozzymandeus said:
No this is an M112; it s a 3.7 and a pre facelift.

Also I note the fuel filler cap is being held shut with tape, suggesting more central locking maladies - PSE pump and boot aquarium seem likely.
Yup, PSE pump likely the culprit. The boot is poorly aligned (the shut lines get wider the further back the boot lid is from the screen) which is a classic sign and cause of water ingress and subsequent PSE failure. As a result the soft close probably won't work nor the lumbar adjustment. If these don't work the boot can't fold backwards and allow the roof to work (assuming that's not faulty also).

Unreal

10,299 posts

53 months

Unless you're in the trade and know these cars inside out, I can't see the point in buying this one for £2K when you can get a fully functioning one for £5K, by which time you will also be in the market for an SL500 with lower tax.

If the roof just needed a new battery to get it going it would have been done. Likewise a fuse. That average cost of getting a non-working roof going again made me smile. Cars get sold with non-working roofs because people have tried and failed to fix them for peanuts. No central locking and roof points to the PSE pump at the very least.

£30 and the PSE pump fixed is a dreamworld best case scenario. Much more likely is that the pump has been damaged by a water leak in the boot. Water gets in via the boot seals as a rule, not the rear light clusters. If the pump is fried, then you're looking at more like £500-£1000 for the part, plus fitting, which can be tricky due to fragile connections. Parts can be very expensive but things like discs and pads are cheap.

Galvanising is somewhat overrated. This is not like galvanising a girder. It is a very thin coating and I have seen galvanised cars rust and non-galvanised ones that are sound. Rear arches are definitely a trouble spot and I would not touch a car with any evidence of rust there. It can affect all R230s. Apart from there and the boot floor, I've not seen rust causing a problem anywhere else on the cars.

Having said all that, the R230 is a really nice thing to drive, whatever engine or gearbox it has in it. Cars like the one featured are headed to the breakers along with the rotten ones, and like the XJS, suddenly they'll be a rare sight and prices will start to rise. There might be a Mercedes two seater convertible in their long history that hasn't risen in value eventually but I can't think of one.

Huzzah

28,872 posts

211 months

Along with all the other potential problems didn't these suffer from rear subframe failures?

I love to be the guy that had a go at this one and fixed it for £223, but too old and creaky now (me and the car)

Rob 131 Sport

4,719 posts

80 months

Absolutely no way. You wouldn’t sleep at night with the maintenance/ repair costs.

Unreal

10,299 posts

53 months

Huzzah said:
Along with all the other potential problems didn't these suffer from rear subframe failures?

I love to be the guy that had a go at this one and fixed it for £223, but too old and creaky now (me and the car)
That was the SLK I think.

Venisonpie

4,721 posts

110 months

Huzzah said:
Along with all the other potential problems didn't these suffer from rear subframe failures?
It's the one area you don't need to worry about - they're magnesium.

Kawasaki2000

209 posts

19 months

Here's my cunning plan. Buy it and put it in an actual shed for 10 years. Then get the kids to ring car sos and look appropriately sad when talking about how much it means to me. Get a bow to stern restoration. Sell it.

mart4856

213 posts

52 months

Knackered roof, power steering, airbag warning light and central locking issues before we even start. Unless you know these cars inside out then run away fast unless your wallet and patience enjoys death by a 1000 cuts.

Edited by mart4856 on Friday 7th August 08:21