Parkers overall rating: 4 out of 5 4.0

Miles per pound (mpp) Miles per pound (mpp)

Petrol engines 5.0 - 6.6 mpp
Diesel engines 5.8 - 6.0 mpp
Low figures relate to the least economical version; high to the most economical. Based on WLTP combined fuel economy for versions of this car made since September 2017 only, and typical current fuel or electricity costs.

Fuel economy

Petrol engines 23.2 - 31.0 mpg
Diesel engines 28.8 - 29.7 mpg

If you have the sort of money to indulge in an SL then you won't be too concerned about the running costs. The most frugal version is the SL 350, which is claimed to return 41.5mpg on average. The SL will be fairly expensive to insure while parts and servicing costs will be high.

If you have a green conscience then the cleanest version of the SL is the 350. It emits 159g/km of CO2, which is not too shabby for a sporty convertible with a V6 engine.

The SL has had a chequered past in terms of reliability. There was a recall in 2004 following concerns about reduced braking efficiency and another in 2005 for an issue where the brake pedal required more effort than expected. Then in 2008 there was a further recall for a potential problem with the Active Body Control, which can affect driving stability.

More recent cars have proven to be more reliable.

Ongoing running costs

Road tax (12 months) £240 - £580
See tax rates for all versions
Insurance group 48 - 50
How much is it to insure?