2020 Mazda CX-30 Base, AWDFACTORY OEM SERVICE PROCEDURE

Engine Noise (Us): Notes

ENGINE NOISE (SKYACTIV-G, US) DESCRIPTION AND POSSIBLE CAUSE

Troubleshooting item Engine noise
Description
  • Engine noise from under hood.
Possible cause Buzzing sound is heard from exhaust pipe during cold engine start:
NOTE:
  • During a cold engine start, sound occurs for up to approx. 30 s with fast idle up for a drive-by-wire control and the warm-up promotion spark retard correction for ignition timing control.
  • Sound occurs from drive-by-wire control, ignition control (vehicle is normal)
  • Dynamic damper loose
  • Exhaust system installation condition
  • Intake system installation condition

Squeal, click, or chirp noise:
  • Improper engine oil level
  • Loose installation of solenoid valves
  • Improper drive belt tension
  • Generator installation
  • Auto tensioner bearing malfunction
  • Splash shield or under cover loose (splash water to drive belt)

Thumping/rattling or creaking sound noise:
  • Improper drive belt tension
  • Loose parts
  • Loose fitting heater hoses vibrating the heater hose bracket protector

Hissing sound noise:
  • Vacuum leakage
  • Loose spark plug
  • Air leakage from the intake-air system

Clattering noise:
  • Loose parts

Pulsing sound is heard:
  • Exhaust shutter valve malfunction (VIN M)

Lightly tapping or rumbling noise:
  • Dynamic damper loose
  • Exhaust system loose
  • Intake-air system loose

Other noise:
  • Electric variable valve timing actuator malfunction
  • Hydraulic variable valve timing actuator malfunction
  • Timing chain noise
  • Tappet noise
  • Hydraulic lash adjuster (HLA) noise
Possible cause
WARNING:
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.