Used Mercedes-Benz GL-Class review and buying guide (2006 to 2013): which one to buy and what to check

Which used Mercedes-Benz GL-Class should you buy?

Buy one with the rear parking camera and no oil leaking from the engine. There's only one GL-Class, sold from 2006 to 2013, so you're choosing an engine and an individual car rather than a year. The GL420 CDI is the one singled out for how it drives, though that says nothing about whether it holds up better than the others.

The GL 320 CDI and GL 350 CDI share a 3.0 V6 diesel (OM642) with the ML and E-Class, and the seals under its oil cooler harden and leak on cars from 2006 to 2012. It's a medium-severity fault, so it's a reason to check carefully rather than to rule those engines out. Little else is documented about what goes wrong on a GL, which makes this a thin record, not a clean one.

Don't skip the camera. It's a very big car and you can't see much out of the back, so one without the rear parking camera is hard work every time you reverse into a space or out of a drive.

Which GL-Class engines and gearboxes are the safe choices?

There's no proven safe choice, so a GL 320 CDI or GL 350 CDI comes down to how dry its engine is. Their OM642 V6 diesel carries the oil cooler seal fault, and there's no mileage given for when it starts, so a low-mileage car isn't automatically in the clear. If the seals have already been replaced, ask for the receipt.

The GL420 CDI is the pick for how it drives, but nothing specific about its reliability is documented either way, so give it the same close inspection rather than assuming it's the safer buy. The same goes for the gearbox: there's nothing on it good or bad, and no service intervals to work from, so the car's own paperwork is all you've got.

What should you check when viewing a used GL-Class?

On a GL 320 CDI or GL 350 CDI, shine a torch down into the vee between the cylinder heads: black oil sitting there means the oil cooler seals are leaking. Look at the back of the block and the gearbox bellhousing for drips, and after the test drive, stand by the bonnet and sniff for hot oil.

Get up close to the panoramic glass roof if the car has one. One owner reported in 2012 that the adhesive bonding the glass broke down and let water run inside, which knocked out the indicators, hazards, brake lights, cabin and exterior lights, and the dashboard warnings and controls. Look for stains on the headlining and damp carpets, and ask whether the roof's ever been resealed.

Before you set off, work every light and switch: indicators, hazards, brake lights, interior lights and headlights, plus the warning lamps when you turn the key. Anything dead or flickering on a car with the glass roof is worth questioning hard. Check the rear parking camera's fitted and gives a clear picture, too.

Climb into the third row before you commit. The middle-row seat that folds to let people into the back is on the wrong side for a right-hand drive car, so whoever's in the rearmost seats gets out on the road side rather than the pavement. If you'll use all seven seats often, try it at the kerb before you agree a deal.

Paste the advert into the free check and it runs these against the listing, the MOT history and the DVLA record before you travel.

What does a used Mercedes-Benz GL-Class cost to run?

What do GL-Class owners like about them?

It's a seriously comfortable car to spend a long day in, and the cabin feels refined and properly luxurious rather than utilitarian. The third row isn't an afterthought either: it's a genuine seven-seater, so the rearmost seats are there to be used rather than just to make up the numbers.

It's as capable on a muddy track as it is on the motorway, and all that luxury inside doesn't leave it out of its depth once the tarmac runs out. It's a big, quiet car for long trips that'll still cope when the going turns rough.

• This Mercedes-Benz GL-Class provides an exceptionally comfortable and smooth ride, making long journeys very pleasant for all occupants.
• The GL-Class offers genuine seating for seven adults, providing ample space and comfort for larger families on any trip.
• This vehicle demonstrates immense capability and confidence, performing exceptionally well both on regular roads and challenging off-road terrain.
• The car offers a very refined driving experience, with a luxurious cabin environment that enhances comfort for all passengers.
• The GL420 CDI model delivers immense power and impressive performance, making it a highly capable and enjoyable vehicle to drive.