2020 Hyundai Elantra: Engine knocking sound
Common wear/failure (not a recall)
Symptoms
Owners of the 2020 Elantra report: engine knocking sound. CarComplaints.com lists 4 owner complaints, average mileage 30,150 miles.
NHTSA has 118 owner complaints for the 2020 Elantra in this area. Examples:
- NHTSA complaint ODI #11771334 (filed 10/15/2026): “The car went into 'limp mode' after rpm fluxuation. it's in the shop. blake, a service manager at temecula hyundai, tells me it has "piston slap," which ai says is related to a piston ring recall for this car. blake went on to say it has 2 power train issues …”
- NHTSA complaint ODI #11769728 (filed 10/07/2026): “2020 hyundai elantra, vin [xxx], ~79,239 mi. on or about [xxx], while entering a parking lot at low speed on an incline, i pressed the accelerator but the car had severe power loss and then stalled. it would not move in reverse. all dashboard lights came on on…”
Likely causes
Sources do not establish a single root cause; diagnosis is needed. Owner-reported fixes are listed below.
Fix, in plain English
Most common owner-reported solutions on CarComplaints.com: replace engine (1 reports). Check for open recalls and extended warranty coverage with a dealer before paying out of pocket.
DIY difficulty: Pro
Internal engine work (lifters, oil consumption, fuel dilution diagnosis) requires engine teardown or dealer software/tests. (Our assessment.)
Cost
No sourced cost range: get a written quote after diagnosis.
Typical parts (search links, no affiliate codes)
AutoZone · O'Reilly · Advance · RockAuto
Sources
Page last updated .