Used Mazda CX-7 review and buying guide (2007 to 2012): which one to buy and what to check

Which used Mazda CX-7 should you buy?

Steer clear of the 2009 to 2012 2.2 diesel unless it passes every injector check, because it carries a serious known fault that's destroyed engines. The copper washer sealing an injector (usually number 1) can leak, or the injector can work loose, and hot gas bakes the oil around the camshafts into hard carbon. That carbon breaks off, blocks the oil pickup and starves the engine.

That leaves the 2.3 turbo petrol, but don't read it as a proven buy. It isn't touched by the diesel's injector problem, and that's the only thing in its favour here, because there's almost nothing on record about it, good or bad. Choose it to dodge one known fault, not because it's shown itself to be reliable.

Whichever engine you go for, the transfer box needs the same scrutiny. Two owners have had one fail, and one of those was on a petrol, so it isn't a diesel-only worry. Production ended in August 2012, so even the last cars are well into old age now.

Which CX-7 engines and gearboxes are the safe choices?

The 2.2 diesel is the engine to be wary of: its injector seal fault is rated High and shows up between 32,000 and 45,000 miles. Three owners had engines fail at 32,000, 38,000 and 45,000 miles, and two of those cars had been serviced by Mazda dealers from new. One failed just 800 miles after a dealer service, so a fully stamped book doesn't protect you.

Mazda offered goodwill on some of these, saying it'd pay part of one owner's £8k bill and offering another a share of a new engine, while a third owner was quoted £7,500 for a replacement. Don't count on that kind of help on a car this age. If you still want the diesel, insist on an invoice for injector seal work.

The 2.3 turbo petrol doesn't have the diesel's injector fault, but it's unproven rather than safe, because the record on it is thin. There's nothing on record about the CX-7's gearboxes themselves; the drivetrain part with reports against it is the transfer box, and it's the one to ask about on either engine.

What should you check when viewing a used CX-7?

On a diesel, look closely around each injector for black, tar-like deposits, which point to a blowing seal. With it running, listen for a chuffing or ticking noise from the top of the engine, and check the oil pressure warning light goes out and doesn't come back on during the test drive. Any of those on a 2009 to 2012 2.2 diesel is a reason not to buy it.

Ask whether the transfer box has ever been replaced, and get the paperwork if it has. A Mazda dealer quoted one owner £6k to replace the box on a 2009 petrol at 75,000 miles. Another's failed at 4 years old, and they suspected the replacement sat slightly out of line, wearing the crankshaft end bearing until metal filings got into the oil and the engine died.

Ask for proof the 2017 front suspension recall has been done. Water can get into the front lower ball joint, causing noise from the front end and, at worst, a joint that fails and upsets the steering. The fix was a new lower suspension arm, so there should be an invoice or a recall entry in the history.

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 Mazda CX-7 cost to run?