BMW 340i (F30) Review: 47/70

The Buyer's Guide

This guide takes our seven categories one at a time: the figures first, then what they mean for the decision. We scored the car as a 2016-2018 340i sedan with the B58 turbo six, the eight-speed automatic and rear-wheel drive, and it landed at 47 out of 70, with a verdict of Buy with the TSB work on record.

Who it is for, in one line: someone who wants a rear-drive BMW six in a sedan, who will ask for the service records on three known B58 items, and who will get an insurance quote before agreeing a price.

All money figures use the same assumptions as every car we cover, so they compare: 12,000 miles a year, insurance for a 40-year-old with a clean record on full coverage, and premium fuel at $4.00 a gallon. Prices are Kelley Blue Book private party in Good condition, on a 2017 sedan; KBB does not say what mileage it assumes. We scored the rear-drive eight-speed automatic; the six-speed manual and the xDrive are noted but not scored. The scope is 2016-2018, because fueleconomy.gov lists a sedan 340i for 2016, 2017 and 2018 only, and every listing in our sample is one of those years. The later B58 in the Supra and the M340i is a different tune, and none of its figures are borrowed here.

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The Deal

~ our estimate, not a measured or quoted figure · * there is a caveat, and the note under the table explains it. Why we mark figures

Kelley Blue Book values a 2017 340i sedan at $19,420 in Good condition, private party, inside a full condition range of $17,020 to $21,270. KBB does not say what mileage it assumes, and it does not split this trim page by transmission.

The asking market is a separate number. The cars.com hub page lists 35 nationwide rear-drive 340i cars from 2016 to 2018, and the 23 that loaded for us have a median asking price of $23,325, in a range from $13,199 to $32,995. That is 1.20 times book. The median car in that sample has 92,943 miles on it, in a range of 20,783 to 142,985. cars.com's own search page sits behind an interactive Cloudflare check, so this is the hub page and not a full count.

The Deal score has two halves. What you lose: KBB's resale history for a 2017 340i Sedan runs $20,669 in 2023, $16,761 in 2024 and $15,570 in 2025, 13.2% a year, or about $2,565 a year on the $19,420 buy-in. We leave out KBB's “Now” row of $19,000, because it is today's private-party price and not the same series. What you get: 11.55 lb per hp usually costs about $13,730 across our Board, so $19,420 is 1.41 times the going rate. That is $60.7 per horsepower on book, and $72.9 on the asking median.

On those two figures our rule reads 3: lose 1, because $2,565 a year is over our $2,000 floor, and get 2, because the price is 1.41 times the going rate. The Risk is 7, above the cap, so nothing holds the Deal down.

For named comparisons, the 335i F30 is $12,690 on book for 300 hp and loses about $2,404 a year. The M340i is $36,360 on book and loses about $4,068 a year.

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The Drive

320 hp at 5,500 rpm and 330 lb-ft from 1,380 to 5,000 rpm, in 3,695 lb: 11.55 lb per hp, with a 51/49 weight split front to rear. That is the rear-drive automatic. The manual is 3,665 lb and the xDrive automatic is heavier at 3,820 lb.

BMW's own US data sheet states 320 hp for every 340i configuration. European figures around 322-326 hp (240 kW) circulate, and we use the certified US one.

We have no 0-60 time to give you. The outlets that run instrumented tests, Car and Driver, MotorTrend, Road & Track and Edmunds, are all blocked to us. BMW's own claim is 4.8s for the automatic and 4.9s for the manual, which is the maker's number and not a test, so treat it as context.

The engine is the 3.0-litre B58, a twin-scroll turbo inline-six. We score powertrain character a 4, characterful. The later B58 in the Supra makes 382 hp and 368 lb-ft, 62 hp more from what reads as the same engine family, so none of that car's figures belong to this one.

The steering is the other half. The F30 runs electric power assist, the same as the 335i F30, and we score its feel a 3, precise but numb. The E90 335i's hydraulic rack is the one that scores a 4. That is a judgment about feel and not a measurement.

For comparison, the 335i F30 makes 300 hp and 300 lb-ft in 3,571 lb, 11.9 lb per hp, and its Drive is a 7 as well. The M340i makes 382 hp in 3,849 lb, 10.08 lb per hp, and its Drive is an 8. Cornering is not in this score; that is The Limit.

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The Upkeep

About $5,059 a year: $1,920 in fuel, ~$1,992 in insurance, $497 in tires and $650 in service. That sits in our $4,700 to $5,150 band, and it is why the Upkeep is a 6. The insurance line is our estimate, and the next two paragraphs say why.

Insurance is where the published figure and our score part ways. MoneyGeek's “340i Sedan 4d” row puts full coverage at $265 a month, $3,180 a year, for a 40-year-old, unmarried, with a clean record and good credit, at 100/300/100 with $1,000 deductibles. That is the same Group A basis the Board's budget tier uses. The minimum-coverage figure in the same row is $136 a month.

Here is the part that does not fit. The same MoneyGeek table prices the M340i, the faster and more powerful trim, at $234 a month, $2,808 a year, and the 335i Sedan 4d this car replaced at $166 a month, $1,992 a year. The 340i xDrive row is $309 a month, $3,708 a year, and the four-cylinder 328i and 330i sedans run $166 to $220 a month. A row that prices this car above its own faster successor does not read as the car, so we do not score on it: the Upkeep carries the 335i row, ~$1,992, as an estimate. The $3,180 row stays here as a warning that some insurers do price this car higher. Either figure is a published average and not a quote for you, so get your own before you agree a price.

Fuel is $1,920. fueleconomy.gov rates the 2017 rear-drive automatic at 25 mpg combined, 21 city and 32 highway; the manual is 23 mpg. BMW's data sheet gives AKI 89 as the minimum and AKI 91 as the recommended fuel, so we price it on 91 at the Board's $4.00 a gallon.

The factory tires are staggered run-flats, 225/45R18 91Y at the front and 255/40R18 95Y at the rear. Tires are on our Board tire rule, the same for every sedan we cover: a Continental ExtremeContact Sport 02 in the factory sizes, priced at SimpleTire, one set every 24,000 miles. That is $237.99 a front and $258.99 a rear, a $993.96 set, or $497 a year, priced as a non-run-flat like every car on the rule. The xDrive cars get a square all-season set instead.

Against the 335i F30's $4,996 a year, this car costs a little more to run on our estimate: the two share tire sizes and our insurance line, its service line is dearer, and its 25 mpg takes some of that back. The M340i is $6,025 a year.

What year one costs, by condition

These are our estimate at 120,000 miles, parts plus an assumed $150 an hour of independent-shop labor. The pieces: the oil filter housing at $650 to $950, the coolant vent-line coupling at $200 to $400, the PCV valve cover at $650 to $900, a water pump or intercooler auxiliary pump at about $450 to $850, and one staggered run-flat set at about $1,200. Nothing here is a single huge bill, but a neglected car stacks several of them. They are the same items listed under The Risk, priced into a first year and not repeated as a second estimate.

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The Risk

Our rubric's 7 is many small failures and no single killer. On this car there is no catastrophic mode in scope: a cluster of four B58 items, each under $1,000, and BMW's own service bulletins name three of them for this exact car and these years.

The oil filter housing insert can break apart and let oil and coolant mix. The repair is $650 to $950, with the genuine housing kit about $644 in parts plus labor. BMW covered it in TSB B110120, revised as B110321, and issued a special removal tool for the B58. The bulletin does not tie it to a mileage.

The PCV valve is built into the valve cover, and the repair is $650 to $900, the genuine cover being $621.99 in parts alone. TSB B011423 extends BMW's factory warranty on this part to 15 years or 150,000 miles. That is worth asking about before you pay anyone.

The coolant vent-line coupling at the cylinder head can break, and it costs $200 to $400. It has its own TSB, B170121, for this exact car and years.

The fourth is the water pump or the intercooler auxiliary pump, $450 to $850 depending on which one. The main mechanical pump is about $444 in parts and the auxiliary electric pump $126 to $339. This is owner-forum wear with no TSB and no recall behind it, and the cost is our estimate from genuine BMW parts prices plus labor.

One recall reaches the car: 18V465000, a crankshaft position sensor that can carry incorrect firmware and stall the car. Dealers replace the sensor free, and it is filed against the 2018 model year only. A VIN lookup settles it.

NHTSA tags 13 complaints to the 340i itself across 2016-2018, 5, 5 and 3, against 93, 73 and 59 for the whole 3 Series nameplate in the same years, which is 5.4%, 6.8% and 5.1%. None of the four items above shows up as a safety complaint. What does is three sunroofs that shattered without contact, all 2017, and two radiators holed by road debris, 2017 and 2018. BMW answered the radiators with a rock guard on cars built from December 2017. The counts are not adjusted for how many cars were sold.

A pre-purchase inspection catches each of the four only partly. A coolant and oil cross-check finds a leak that has started, and a coolant level and a look at the line find a coupling that is already weeping. An insert, a valve or a coupling that has not failed yet shows nothing, so the service records are the better test. The cluster sits in BMW's bulletins for the 340i and the 340i xDrive alike, and it does not split by transmission.

The 335i F30 scores a 5, with a fuel pump that costs $2,000 to $3,500 and that an inspection cannot rule out. The M340i scores a 6, with a worst case of $2,100 to $8,000 that is disputed. This car sits above both.

The inspection checklist

1. Check the coolant level and look for stains
2. Ask about the oil filter housing TSB work
3. Scan for oil and coolant cross-contamination
4. Listen for water pump whine on a cold start
5. Check for oil seep at the valve cover
6. Confirm the 18V465000 sensor recall is done, on a 2018

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The Daily

Five seats, four doors and a 17 cu ft trunk, from the SAE figure in BMW's 2017 US data sheet. The same sheet gives 54 cu ft of front seat volume and 42.2 cu ft in the rear. It is a conventional sedan, and it can be the only car you own.

The screen is iDrive. Apple CarPlay was available as a factory option from the 2017 model year, which means it is not standard and not on every car: treat a 2016 as CarPlay-less unless the listing says otherwise.

Against the 335i F30's 17.0 cu ft, the trunk is the same, and that car has no factory CarPlay in any year. The E90 335i has 12.0 cu ft. An 8 is the sedan ceiling on our rubric.

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The Limit

F Street, on the 2026 SCCA Solo rules, where Appendix A lists “3 Series (F30/F31 chassis; 6-cyl Turbo, non-M3) (2012-20)”. SCCA classes by chassis and drivetrain and not by trim name, so the earlier 335i on this chassis sits on the same line.

It is rear-wheel drive on staggered 225/45R18 front and 255/40R18 rear run-flats, carrying 3,695 lb. The xDrive cars get a square all-season set instead. We have no grip figure, because the outlets that publish skidpad numbers are blocked to us. We score it a 6, competent rather than sharp, alongside the 335i F30 and the G37.

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The Mods

The first step is a Stage 1 ECU flash with no hardware: BootMod3 or MHD Flash. BootMod3 is a $595 software license plus a $50 map pack, about $650. A BM3 tuning guide reports Stage 1 at 360-410 whp depending on fuel: 360-380 on 91 octane, 370-390 on 93 and 390-410 on a 30% ethanol blend. It reports Stage 2, a catless downpipe and intake, at 390-440 whp.

What we do not have is a stock-dyno baseline. The guide does not state one, and we found no other citable source, so we cannot say what an untouched car makes at the wheels or state the gain to the number. The gain from software alone is real, and it is not precisely quantified. Dyno figures are not comparable with the 320 hp crank rating, or across different dynos. Our figure of about $650 per +100 whp is an estimate for exactly that reason, since no two of our sources were read off the same dyno. The path prices are our estimates, except the software, which is BootMod3's own.

The aftermarket is shared across BMW's B58 cars: the M240i, 440i, Z4 and X3 M40i, plus the later Supra, whose B58 is a different tune and never lends this car its figures. We give it four figures or less for a transformation on a bottom end that takes it, the same read as the M340i on the same engine family.

The catch is the Risk section again. BMW's bulletins cover the oil filter housing, the PCV valve and the vent line on stock, un-tuned cars. A flash raises boost and underhood heat, which stresses the same plastic parts, so a tuned car plausibly reaches the same failure sooner and not a different one. That is an argument from how the parts and the tune interact, and not a measured failure rate.

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The Verdict

Buy one with the oil filter housing, PCV and coolant-line work on record, get an insurance quote before you agree a price, and expect about $2,565 a year to go back to depreciation. It scores 47 out of 70, level with the G37, the Miata NC, the 370Z, the Mustang GT and the Focus RS: a 9 for the Mods, an 8 for the Daily, a 7 for the Drive and a 7 for the Risk, a 6 for the Upkeep, held back by a 3 for the Deal.

We scored the rear-drive automatic, and the market runs the other way. Of 93 nationwide cars.com “340” listings, 35 are rear-drive and 58 are xDrive, 37.6% to 62.4%. None of the 23 listings we read in detail is titled as a manual, but cars.com titles do not state the transmission, so that is an inference and not a share. BMW's own data sheet lists the manual on both rear-drive and xDrive cars, and we do not put a number on how many were sold. For the years, we scored 2016-2018, because that is when the sedan was sold as a 340i in the US: the only 2019 340i is the xDrive Gran Turismo, a different body.

This car is for you if you want a B58 in a sedan with a repair list that stays under $1,000 an item and the insurance quote comes back near our ~$1,992 estimate rather than MoneyGeek's $3,180 row. It is not for you if you were counting on a cheaper BMW six and the quote is higher. The 335i F30 is $12,690 on book, with a fuel pump that costs $2,000 to $3,500.

The Long Read: Should You Buy a Used BMW 340i (F30)?

We scored the 340i as a 2016-2018 sedan with the B58 turbo six, the eight-speed automatic and rear-wheel drive, and it landed at 47 out of 70, with a verdict of Buy with the TSB work on record.

So you want a rear-drive BMW six with four doors, and you have heard the B58 is a good one. A used 340i gives you 320 hp and 330 lb-ft for $19,420 on book, its repair list is a cluster of small items that each cost under $1,000, and the running cost lands near $5,059 a year on our insurance estimate, though one published insurance row says you could pay a lot more.

We scored the rear-drive automatic. The six-speed manual and the xDrive exist and are noted, and 58 of the 93 cars.com listings we counted are xDrive, so check what you are looking at.

How much does a used 340i cost?

Kelley Blue Book values a 2017 340i sedan at $19,420 in Good condition, private party, with a range of $17,020 to $21,270 across conditions. KBB does not say what mileage that assumes. The market asks more: the median across 23 cars.com listings is $23,325, which is 1.20 times book, on cars with a median of 92,943 miles.

Is the 340i expensive to insure?

Maybe. MoneyGeek's “340i Sedan 4d” row says $265 a month, $3,180 a year, on the same profile we use for every car. But the same table has the M340i, the faster and more powerful trim, at $234 a month, $2,808 a year, and the 335i Sedan 4d at $166 a month, $1,992 a year. A row that prices this car above its own successor does not read as the car, so we score on the 335i row, ~$1,992, as an estimate. Both are published averages and not a quote for you, so get your own before you agree a price.

How fast does the 340i depreciate?

About 13.2% a year on KBB's history for a 2017 340i Sedan: $20,669 in 2023, $16,761 in 2024 and $15,570 in 2025, or about $2,565 a year on the buy-in. On our rule that is lose 1, and $19,420 is 1.41 times the $13,730 that 11.55 lb per hp usually costs across our Board, which is get 2. The Deal is a 3.

What goes wrong with the 340i?

Four small things, each under $1,000, and BMW's own bulletins name three of them for this car. An oil filter housing insert can break apart and let oil and coolant mix, $650 to $950, in TSB B110120 and its revision B110321. The PCV valve in the valve cover is $650 to $900, and TSB B011423 extends BMW's warranty on it to 15 years or 150,000 miles. A coolant vent-line coupling at the cylinder head is $200 to $400, in TSB B170121. The fourth is a water pump or intercooler auxiliary pump at $450 to $850, owner-reported and not in any bulletin.

One recall reaches the car, 18V465000, a crankshaft position sensor on 2018 cars that can carry incorrect firmware, and the free fix replaces the sensor. NHTSA tags 13 complaints to the 340i across 2016-2018, and none of them is one of the four items. There is no catastrophic mode in scope, and that is a 7 for the Risk.

Is the 340i expensive to run?

Not badly, on our estimate. About $5,059 a year: $1,920 in fuel at 25 mpg, ~$1,992 in insurance, $497 in tires and $650 in service. That sits in our $4,700 to $5,150 band, so the Upkeep is a 6. The 335i F30 is $4,996 a year. The tires are staggered, and a set on our Board tire rule is $993.96.

How does the 340i drive?

Well, and with a fair amount of character: 320 hp and 330 lb-ft in 3,695 lb, with the torque arriving at 1,380 rpm. We have no 0-60 time we can cite, and BMW's own 4.8s for the automatic is a claim and not a test. The steering is electric assist, the same as the 335i F30, and we call its feel precise but numb. We score the Drive a 7. The Supra's B58 makes 382 hp, and none of that car's figures are this one's.

Can a 340i be your only car?

Yes. Five seats, four doors and a 17 cu ft trunk. Apple CarPlay was a factory option from the 2017 model year and not standard, so check the listing, especially on a 2016.

Is the 340i any good at autocross?

It runs in SCCA's F Street, on staggered 18-inch run-flats and rear-wheel drive, carrying 3,695 lb. We have no grip figure for it, and we score its Limit a 6.

Should you tune a 340i?

It is cheap to start. A Stage 1 flash is about $650 with no hardware, and a BM3 tuning guide reports 360-410 whp depending on fuel. We have no stock-dyno baseline, so we cannot state the gain to the number, and our figure of about $650 per +100 whp is an estimate. The catch is that more boost and heat lean on the same plastic parts BMW's bulletins cover.

340i buy or skip: the verdict

Buy one with the oil filter housing, PCV and coolant-line work on record, get an insurance quote before you agree a price, and expect about $2,565 a year to go back to depreciation. Ask for the service records, check the coolant and the oil for cross-contamination, and on a 2018 run the VIN for 18V465000.

The 340i finished at 47 out of 70 on our Board, level with the G37, the Miata NC, the 370Z, the Mustang GT and the Focus RS. It loses points to a Deal of 3, and wins them back with a 9 for the Mods and an 8 for the Daily.