Is the 2021 Bmw M340I reliable?

The 2021 Bmw M340I has 13 complaints filed with NHTSA (1.0x the segment average). Our reliability verdict: average. Most common issue: ENGINE problems.

What are common problems with the 2021 Bmw M340I?

Top problems: ENGINE (5 complaints, avg repair $500); TRANSMISSION (3 complaints, avg repair $500); BRAKES (1 complaints, avg repair $500). Issues typically appear around 50K miles.

Are there any recalls on the 2021 Bmw M340I?

Yes, there are 6 recall(s): SEAT BELTS, ELECTRICAL SYSTEM:12V/24V/48V BATTERY, BACK OVER PREVENTION: SENSING SYSTEM: CAMERA, SEAT BELTS:FRONT:BUCKLE ASSEMBLY, SEATS, SEAT BELTS. Contact any Bmw dealer to verify if recalls have been completed on your specific vehicle.

How much does it cost to fuel a 2021 Bmw M340I?

The 2021 Bmw M340I gets 26 MPG combined. At current US average gas prices, driving 12,000 miles per year costs roughly $1846. See the interactive fuel cost calculator on this page for state-specific pricing.

How much does it cost to insure a 2021 Bmw M340I?

Estimated US average full-coverage insurance for the 2021 Bmw M340I is approximately $2,250/year (sedan-luxury class). Actual quotes vary heavily by state, driver age, driving record, and credit — see the interactive insurance estimator on this page for state-specific pricing.

2021 Bmw M340I

Problems, Recalls & Reliability Report

Average

Quick Summary

The 2021 Bmw M340I has 13 owner complaints filed with NHTSA — that's 1.0x the segment average of 13. The most common issue is engine problems (38% of all complaints), specifically: at approximately 20,000 miles, vehicle indicated excessively low oil. the dealer indicated oil level was excessively low but did not identify the problem,. the vehicle was filled and returned to owner. within 1000 miles, the incident occurred again. dealer replaced replaced the valve cover claimin. There are 6 recalls issued for this model year.

Total Complaints

Recalls Issued

—/5

Safety Stars

1.0x

vs Segment Avg

Known Problems(top 5 of 7)

ENGINE

5 complaints

38%

• At approximately 20,000 miles, vehicle indicated excessively low oil. The dealer indicated oil level was excessively low but did not identify the problem,. The vehicle was filled and returned to owner. Within 1000 miles, the incident occurred again. Dealer replaced replaced the valve cover claimin
• At approximately 20,000 miles, vehicle indicated excessively low oil. The dealer indicated oil level was excessively low but did not identify the problem,. The vehicle was filled and returned to owner. Within 1000 miles, the incident occurred again. Dealer replaced replaced the valve cover claimin
• I am reporting a safety concern involving BMW vehicles equipped with the B58 Technical Update (B58TU) engine, commonly found in model years 2019–2021. These vehicles utilize a variable-displacement engine oil pump containing an internal thermoplastic adjusting component responsible for regulating o

Typical onset: 50K miles Est. repair: $500

“At approximately 20,000 miles, vehicle indicated excessively low oil. The dealer indicated oil level was excessively low but did not identify the problem,. The vehicle was filled and returned to owner. Within 1000 miles, the incident occurred again. Dealer replaced replaced the valve cover claimin”

— NHTSA complaint filing

Recalls (6)

SEAT BELTS21/07/2021

BMW of North America, LLC (BMW) is recalling certain 2021 2 Series (230i, 230i xDrive, M240i, M240i xDrive), 330e, 330e Xdrive, 4 Series Coupe (430i, 430i xDrive, M440i xDrive) M4 Coupe, M4 Competition Coupe, BMW 4 Series Convertible (430i, M440i), BMW X1 sDrive28i, xDrive28i, 2 Series Gran Coupe (228i, 228i xDrive, M235i xDrive), M2 Competition Coupe, 330i, 330i xDrive, M340i, M340i xDrive, M3, M3 Competition, 530i, 530i xDrive, 540i, 540i xDrive, MINI Hardtop 2 Door (Cooper, CooperS, JCW), X2 sDrive28i, X2 xDrive28i, X2 M35i, Z4 sDrive30i, Z4 M40i, MINI Hardtop 2 Door (Cooper SE), MINI Convertible (Cooper, Cooper S, JCW), MINI Clubman (Cooper S, Cooper S All4, JCW), MINI Countryman (Cooper, Cooper All4, Cooper S, Cooper S All4, JCW All4), Rolls Royce Ghost, MINI Countryman (Cooper S E All4), Rolls Royce Phantom, Rolls Royce Cullinan, and Toyota Supra vehicles. The passenger seat belt Automatic Locking Retractor (ALR) may deactivate early, before the webbing fully retracts. As such, these assemblies fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 208, "Occupant Crash Protection."

Risk: During a crash, a seat belt retractor that does not function as intended increases the risk of injury.

Fix: Dealers will inspect the seat belt retractors (including the seat belts) and, if necessary, replace the retractors, free of charge. Owner notification letters were mailed on September 3, 2021. Owners may contact BMW customer service at 1-800-525-7417; 1-866-825-1525 (MINI); 1-877-877-3735 (Rolls Royce); and 1-888-270-9371 (Toyota).

Fuel Cost Calculator for 2021 Bmw M340I

Live EIA prices

Annual miles driven: 12,000

Your state (affects local gasoline price)

Per year

$1,847

Per month

$154

Per mile

15.4¢

MPG

City driving (worst-case MPG)

$2,087/yr

Highway driving (best-case MPG)

$1,500/yr

Based on EPA fuel-economy ratings and EIA weekly retail prices (2026-07-20). Real-world cost varies with driving style, trim/engine, terrain, and traffic.

5-Year Gas Price History

EIA weekly retail data · 2021 → today

Show:

Current

$4.00

5-year low

$2.78

5-year high

$5.01

Since 2021

+27%

Source: US Energy Information Administration weekly retail gasoline prices.

Estimated Insurance Cost for 2021 Bmw M340I

Estimate only, not a quote. Modeled from NAIC + HLDI averages for a hypothetical 35-year-old driver with clean record + full coverage. Your actual quote depends heavily on your age, driving history, credit, ZIP code, and insurer.

Your state (affects local premium average)

Full coverage / year

$2,250

Full coverage / month

$188

Liability only / year

$710

vs US avg

+34%

How this estimate is calculated

US base full-coverage premium$1674

× state (US)1.00x

× vehicle class (sedan-luxury)1.28x

× theft risk1.00x

× safety rating1.00x

× vehicle age1.05x

= Full coverage estimate$2250

Coverage assumed: 100/300/100 liability + comprehensive/collision, $500 deductibles. Data sources: NAIC 2024 + HLDI loss studies.

Maintenance & Warranty

Recommended Bmw M340I Service Intervals

Oil change

10K mi / 12 mo

Tire rotation

10K mi

Brake fluid

24 months

Transmission fluid

60K mi

Engine coolant

100K mi

Spark plugs

60K mi

Cabin air filter

15K mi

Engine air filter

30K mi

Differential (AWD/4WD)

60K mi

Condition-Based Service (CBS) tells you exactly when service is due. Transmission fluid was labeled 'lifetime' but many owners service at 60K-100K.

"Severe service" conditions (heavy towing, extreme temps, city stop-and-go) typically halve these intervals. Always consult your vehicle's owner's manual for the authoritative schedule.

Bmw New-Vehicle Warranty Coverage

Bumper-to-bumper (basic)

4 yr / 50K mi

Powertrain

4 yr / 50K mi

Hybrid/EV battery

8 yr / 100K mi

Corrosion (rust perforation)

12 yr / unlimited mi

Roadside assistance

4 yr / unlimited mi

Corrosion is unlimited miles for 12 years

These are the terms for a new Bmw. If you're buying a used 2021 M340I, remaining coverage is usually pro-rated from the vehicle's original in-service date. Not all coverage transfers between owners — check with a Bmw dealer for VIN-specific remaining warranty.

Estimated Repair Costs

ENGINE(~50K mi)

$500

TRANSMISSION(~50K mi)

$500

BRAKES(~50K mi)

$500

SUSPENSION(~50K mi)

$500

STEERING(~50K mi)

$500

Estimates based on average reported repair costs. Actual costs vary by location, shop, and severity.

🔍 Pre-Purchase Inspection Checklist

Based on 13 owner complaints for this specific year, here's what to check or ask about:

☐
ENGINE: At approximately 20,000 miles, vehicle indicated excessively low oil. The dealer indicated oil level was excessively low but did not identify the problem,. The vehicle was filled and returned to owner. Within 1000 miles, the incident occurred again. Dealer replaced replaced the valve cover claimin
Typically appears around 50K miles. Repair cost ~$500
☐
TRANSMISSION: The contact owns a 2021 BMW M340I. The contact stated while driving various speeds, the vehicle independently shifted from reverse(R) to drive(D) to park(P). The contact stated that while driving approximately 10 MPH and attempting to stop the vehicle, the brake pedal was depressed and went to the f
Typically appears around 50K miles. Repair cost ~$500
☐
BRAKES: The contact owns a 2021 BMW M340I. The contact stated while driving various speeds, the vehicle independently shifted from reverse(R) to drive(D) to park(P). The contact stated that while driving approximately 10 MPH and attempting to stop the vehicle, the brake pedal was depressed and went to the f
Typically appears around 50K miles. Repair cost ~$500
☐
SUSPENSION: Started as low creaking noise coming from front left wheel. Slow speeds, over small bumps. Over time (one month), creaking noises became louder and more frequent. At that time, steering was starting to feel stiff when turning to the left. Taken to 2 BMW dealerships who said it was just a noise and
Typically appears around 50K miles. Repair cost ~$500
☐
RECALLS: Verify all 6 recalls have been completed — free at any Bmw dealer
☐
General: Get a pre-purchase inspection from an independent mechanic ($100-$200)

Bmw M340I — Year Comparison

How does 2021 compare to other years? Fewer complaints = more reliable.

2022

8Excellent Reliability

Full years-to-avoid analysis →

NHTSA Safety Rating

No NHTSA safety rating available

At a Glance

Complaints: 13
Recalls: 6
Fire reports: 0
Crash reports: 0
Injury reports: 0
Segment avg: 13

Check a Specific VIN

See recalls for YOUR 2021 Bmw M340I

Compare With

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