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What 3 owners told NHTSA about the 2020 BMW 4 Series Gran

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (3)Crash / fire / injury (1)Airbags (1)Brakes (1)Engine & cooling (1)

1 of 3 complaints match · Engine & cooling · clear filters

Apr 14, 2025Engine & cooling

The contact owns a 2020 BMW 430I. The contact stated while driving 55 MPH, the low coolant warning light was illuminated, and the message "Engine Overheating" was displayed. The vehicle was parked at the place of employment. The coolant level was checked an hour later by the contact’s husband, and the coolant level was low. The contact stated that her husband added coolant to the reservoir and observed coolant leaking underneath the engine compartment. The contact stated that later in the day, while driving at an undisclosed speed and the failure reoccurred. The vehicle was taken to a dealer where it was diagnosed; however, the location of the leak was undetermined. The manufacturer was notified of the failure. The failure mileage was approximately 66,475.

NHTSA ODI 11654427

Working with the data? Download all 3 complaints as CSV · fetched from NHTSA July 19, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2020 BMW 4 Series Gran verdict →