Check a vehicle VIN check Latest recalls Latest complaints Common problems Rankings Compare vehicles Recall roundups All makes Guides Share your experience
Theme

Engine & cooling

2021 BMW 4 Series Engine problems

Owners have filed 3 complaints about the 2021 BMW 4 Series's engine & cooling with NHTSA - 20% of all its complaints, most recently on April 27, 2026. Stalling, loss of power, oil consumption, overheating, head gaskets, timing chains and engine failure.

Complaints
3
Recalls
0
Crashes
0
Fires
0
Injuries
0
Deaths
0

Engine complaints

Engine & cooling

The recall was issued more than 8 months ago but the remedy is still not yet available, which is very concerning as the problem may cause the event of fire even when the vehicle is parked. Issued SEP 23, 2025 Description of Problem It is possible for water to contact and enter the engine starter. This could lead to corrosion which could cause a short circuit. Safety Risk This could increase the risk of a thermal event or fire during driving or even when the vehicle is parked and the ignition is off.

Filed Incident EngineNHTSA 11734108
Engine & cooling

The engine Unknown The problem was confirmed by BMW as they sent me a notice. Unknown Unknown

Filed Incident EngineNHTSA 11729210
Engine & cooling

The component that malfunctioned is the engine starter relay, which is subject to an open BMW/NHTSA safety recall (issued September 2025) due to potential corrosion causing overheating, short circuits, and vehicle fire risk. The recall specifically advises parking the vehicle outside and away from structures until repaired. The vehicle is available for inspection upon request.My safety and the safety of my family were put at risk because the dealership (Capitol Nissan in San Jose) failed to disclose this critical...

Read the full complaint

fire-risk recall before or during the sale on January 4, 2026, despite it being noted on the provided Carfax report (without any explanation of its severity). I only learned of the fire hazard and "park outside" warning when an authorized BMW dealer informed me during an inspection on January 5, 2026.The recall issue has been confirmed by an authorized BMW dealer on January 5, 2026.The vehicle has been inspected by an authorized BMW dealer, but not yet by the manufacturer, police, or insurance representatives.There were no warning lamps, messages, or other symptoms that I noticed prior to purchase, as the problem is related to a latent defect covered by the recall. The issue was UNKNOWN to me until the BMW dealer informed me after the purchase.In addition, the dealership engaged in other fraudulent practices, including structuring my full cash payment as self-financed (with themselves as both seller and creditor) and adding unauthorized charges, but the primary safety concern prompting this report is the undisclosed fire-risk recall.

Filed Incident EngineNHTSA 11709689

BMW 4 Series engine complaints by year

4 Series engine problems, every year

Had a engine problem with your 2021 4 Series? Tell other owners.

Your experience goes live straight away and helps every owner and buyer who checks this vehicle. Anonymous, free, no account.

Overall, how would you rate it? *

0/4000 · Please leave out names, phone numbers and your full VIN.

By posting you confirm it's your own, honest experience and agree to the rules. Safety defect? Also report it to NHTSA - that's how recalls start.

Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked . Complaints are owners' own reports and are not verified. How we use the data

Owners helping owners

Know before you drive.

Every experience you share - good or bad - shows on that vehicle's page and helps the next owner and buyer. Two minutes, anonymous.

Share your experience