Used BMW 4 Series review and buying guide (2013 to present): which one to buy and what to check

Which used BMW 4 Series should you buy?

A 2013 to 2020 diesel is the easier 4 Series to buy with confidence, as long as the paperwork proves its EGR cooler was replaced under the 2018 recall. That recall covered BMW's four- and six-cylinder diesels because a leaking cooler could let soot smoulder in the intake and start a fire, and it's a fix you can confirm on paper rather than a gamble you can't.

Early petrols are the ones to treat with care. Thousands of early N20 engines were built with plastic timing chain guides that could break up with little warning and let the chain jump, and one owner's 2014 420i had a slight chain rattle at 85,000 miles. Nothing on record says which 4 Series petrols use that engine, so any early petrol needs a quiet cold start before you commit.

The Convertible (2014 to 2020) has its own run of owners' reports, and they centre on the roof and windows. One car's side windows kept dropping with the roof up, and two others had a loud roof rattle or a noise from the rear, the latter going quiet each time the seal where roof meets body was cleaned. That isn't a known fault, so it's something to test at the viewing rather than a reason to skip the model.

There's almost nothing on record about the newer 4 Series launched in 2020, and no known faults are logged against any 4 Series at all. That's a gap in the evidence, not a clean bill of health, so a 2020-on car doesn't earn a pass on reputation and needs the same checks as an older one.

Which 4 Series engines and gearboxes are the safe choices?

The diesels are the safer bet once the EGR cooler recall's done, so that's the first thing to ask for on a 420d, 430d or 435d. The 2.0 diesel's timing chain sits at the back of the engine and can stretch until it snaps. There's no set interval for replacing it, so the test is a cold start with your ear tuned to the rear of the engine for a rhythmic scraping.

Among the petrols, the chain guide warning is about early N20 engines, so ask which engine the car has, listen for rattle from cold and ask how often the oil was changed. One 2014 420i's chain was rattling at 85,000 miles despite a full BMW history, which can still mean oil changes as far apart as 20,000 miles. The 3.0 six-cylinder 435i was part of a 2014 worldwide recall because the screws holding the Vanos adjuster housing could work loose or break.

The ZF 8-speed automatic has nothing against it on record beyond its fluid. BMW calls it sealed for life, but ZF, who build it, specify fresh fluid and a new filter, and the interval to hold a seller to is 60,000 miles or 96 months. Clutches aren't spotless either: one 2015 car needed a new clutch and dual-mass flywheel at just 20,000 miles, so on a manual test the clutch for slip.

What should you check when viewing a used 4 Series?

Paperwork comes first on a diesel: ask for the record showing the EGR cooler was replaced under the recall, plus receipts for automatic gearbox fluid and filter changes at 60,000 miles or 96 months. On a Convertible, look for proof of the 2017 seat recall, which fixed front seat bolts that could work loose; a noise from the seat or extra play in it is the giveaway.

Arrange to see the car from cold and listen at the back of the engine for a scrape or rattle from the timing chain. On the drive, watch for any engine or drivetrain warning. One 2016 420d Gran Coupe driven 20km each way in traffic threw a drivetrain warning that seemed to cut the engine, and a 2017 420d Gran Coupe kept misfiring at cruising speed even after an oxygen sensor was changed.

Try everything electrical, air con included. One 2016 420d owner paid £997 after the front electronics module failed and the car lost its lights, power steering and dashboard on the move, and a 2015 car went back to the dealer four times with an air con fault nobody could fix. There's also one report of a 2016 440i catching fire under the bonnet after dropping into limp mode a week after its first service at 19,418 miles, so ask about any warning lights in its past.

With a Convertible, raise and lower the roof and check the side windows stay put with it up, as one 2016 420i's kept dropping. Listen for roof rattles, and on a 440i Convertible feel for vague steering, wandering on the motorway or a front rumble on right turns; one owner's turned out to have a loose steering joint.

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 BMW 4 Series cost to run?

What do 4 Series owners like about them?

There's more room inside than in the 3 Series Coupe it replaced, because the wheelbase is longer. The Gran Coupe is roomy too, especially in the back, even though it's no bigger than the two-door, and its hatchback opening makes it a more versatile shape for carrying things.

The Gran Coupe's ride is a real strength, and it's smooth over the bumps. It's a rear-wheel-drive four-seater built on the 3 Series saloon, with the long bonnet and short tail that give it a proper coupe stance, and the Gran Coupe has more appeal than the saloon it shares so much with.

• The longer wheelbase of the 4 Series provides increased interior space for occupants.
• The 4 Series Gran Coupe offers impressive interior space, particularly in the rear, despite being the same size as the Coupe.
• The 4 Series Gran Coupe possesses more aesthetic appeal compared to a 3 Series saloon.
• Its hatchback design provides enhanced versatility for the 4 Series Gran Coupe.
• An electric tailgate is included as standard equipment on all 4 Series Gran Coupe models.