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

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

Go for a diesel from 2010 onwards: that's when the R-Class went from six seats to seven, and the known fault on the diesels is a Medium-rated oil leak rather than the High-rated one the petrol carries. The one to be wary of is the R 350 petrol built from 2006 to 2008, which has a High-rated fault in the sprocket that drives its balance shaft.

That petrol fault is serious. The sprocket's made of metal that's too soft, so its teeth wear down, the camshaft timing slips out of step and the engine light comes on. Don't treat an early R 350 petrol as a safe buy unless the seller can show an invoice proving the balance shaft sprocket has already been replaced.

The diesel fault belongs to the engine rather than the badge: the R 280 CDI, R 320 CDI and R 350 CDI all use the OM642 3.0 V6, whose oil cooler seals harden with heat and age and then let oil collect on top of the engine. It's worth checking for on every car, but it isn't a reason to pass over a diesel.

Six-seat diesels from 2006 to 2010 have the same engines and the same oil cooler weak spot, so the later car's edge is the extra seat, not a cleaner record. With only two known faults against the R-Class, the evidence is thin either way, so don't take a quiet record as proof that any version's trouble-free.

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

The diesels are the safer R-Class engines: their known fault is rated Medium, while the 2006 to 2008 R 350 petrol carries a High-rated one. If you're set on that petrol, buy only one with an invoice for a replacement balance shaft sprocket. A 2011 report on the same V6 says Mercedes issued a service bulletin about the sprocket wearing early and calls the repair a big job.

All three diesels share the OM642 3.0 V6, so the oil cooler leak applies whichever badge is on the boot. There's no mileage tied to when the seals give up, so check a low-mileage diesel as carefully as a high one. Nothing's been reported about the gearbox, good or bad, so it won't help you choose between cars.

The R 280 CDI carries one extra warning: a failing turbo actuator can cut the power for a spell, and the fix is a whole new turbo. One-off owner reports add to the bigger diesels' list too. One 2008 R320 CDI with a full Mercedes history began to wear a main crankshaft bearing at 58,000 miles, and a 2011 R350 CDI lost power with a choking noise.

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

On any diesel, lift the engine cover and shine a torch into the vee of the engine beneath the intake: wet or pooled oil there points to the oil cooler seals. Look under the rear of the engine bay for drips or an oily undertray, and sniff for burning oil once it's hot after the test drive. If the seller says the seals have been done, ask for the receipt.

On an R 350 petrol from 2006 to 2008, have the stored engine codes read before you hand over money, and watch for the engine management light, a lumpy idle or hesitation when you pull away. A stored camshaft position code points to the balance shaft sprocket wearing, so ask for the invoice if the seller says it's been sorted.

Drive it hard enough to load the turbo, and treat a brief loss of pull as a reason to stop, especially on an R 280 CDI. Watch the dash too, since one 2011 R350 CDI showed ABS and ESP warnings before it lost power. Listen for knocking from low in the engine, test the steering and suspension over bumps, and run the air conditioning cold.

Ask for proof the recall work was done: the 2011 and 2012 fuel leak recalls, one of them fixed by fitting a new fuel filter, and on a diesel registered from January 2011 the emissions software update called in 2017. A Mercedes dealer can tell you whether that work's on the car's record, so get the answer before you pay.

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

Is a used Mercedes-Benz R-Class W251 (2006 to 2013) worth buying?

Buy a W251 as a diesel from 2010 onwards with a dry engine vee, and skip a 2006 to 2008 R 350 petrol that can't show proof of sprocket work. The later cars have seven seats instead of the original six, which makes them the more useful family buy, while an earlier diesel shares the same engines and isn't any safer.

It's not as sharp to drive as an E-Class or S-Class, and it's hard to feel what the four-wheel drive is adding. Neither the petrol's sprocket wear nor the diesels' oil cooler leak is tied to a mileage, so a low-mileage car needs exactly the same checks as a leggy one.

Approved used status didn't save one R350 bought from a Mercedes dealer in 2016. It went back for steering and suspension work, then spent over a month off the road with its air conditioning, including a new compressor that failed again because a pipe was blocked. The owner's paid-for extended warranty covered it, so ask whether any warranty transfers with the car.

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

What do R-Class owners like about them?

It's Mercedes' version of the people carrier, and its strongest suit is room: there's a huge amount of space inside. That's the reason to choose one, and if space matters more to you than how a car drives, it's where the R-Class earns its place on your driveway.

There's a long wheelbase version as well, which stretches the cabin for even more room. If you regularly fill every seat and still need space for luggage, that's the one to hunt for, so ask which wheelbase a car has before you travel to see it.

• This model offers a practical and spacious alternative to traditional people carriers.
• The R-Class provides a very generous amount of interior space for occupants and luggage.
• The R-Class was offered in a long wheelbase variant, providing significantly increased interior space for passengers and cargo.
• From 2010, the R-Class was offered as a seven-seater, an increase from its original six-seat configuration.