M52 / M52TU / M54 Family

BMW M54B25
BMW M54B25 – photo by Aconcagua

BMW M52 / M52TU / M54 Family

Table of Contents

All Engines


  • Valve cover gasket can leak oil into the spark plug wells
  • VANOS piston seal O-rings can harden and shrink, causing loss of power below 3000rpm, surging around 3000rpm, a louder idle, and rough running – O-rings and Teflon piston seal rings must be replaced


Additional Problems

  • Cylinder liners could fail due to fuels with high sulfur content – this was only a problem in the 90s, as fuel today has much less sulfur in it. Generally speaking, any car that is running today should be fine.



  • BMW 323i (E36)


  • BMW 328i, 328is (E36)
  • BMW 528i (E39)
  • BMW Z3 2.8i (E36/7)



Differences from the M52:

  • “Dual VANOS” – variable valve timing on both the intake and exhaust camshafts
  • Electronic throttle with mechanical backup
  • “Dual-length” intake manifold
  • Revised cylinder liners
  • Aluminum block outside the US

Additional Problems

  • Oil Separator Valve (OSV) / Crank Case Ventilation (CCV)
    • Symptoms are high oil consumption, poor running, and sometimes a whistling noise; located under throttle body
    • 4-8 hours of labor to replace
    • Often caused by a lot of short drives. Sometimes, it can be fixed by a lot of long drives and high revs.



  • BMW 323i (E46)
  • BMW Z3 2.3i (E36/7-E36/8)


  • BMW 328i (E46)
  • BMW Z3 2.8i (E36/7-E36/8)



Differences from the M52TU:

  • Non-return fuel system
  • Electronic throttle with no mechanical backup
  • Electronically controlled thermostat
  • New engine management system
  • New intake manifold
  • Aluminum block in the US

Additional Problems

  • Camshaft sensor (easy to replace) – get an OEM part, not an aftermarket part
  • TSB – in extremely cold climates, moisture can accumulate and freeze in the engine oil separator or dipstick guide tube. This may cause high crankcase pressures which result in valve cover leakage/breakage, or an oil hydrolock condition which can result in catastrophic engine damage. This can be fixed by replacing the crankcase ventilation valve, hoses, and dipstick guide hose.
  • TSB – Deposits in the injection and induction system:
    • Deposits at the fuel injector’s tip – symptoms include hesitation or stumble during acceleration, loss of power, poor fuel efficiency, increased emissions, and/or CEL due to misfires
    • Carbon deposits at the valves or intake manifold ports – symptoms include loss of power, unstable and/or rough idle, increased emissions, and/or CEL due to misfires
    • Combustion Chamber Deposit Interference (CCDI) – pinging or knocking which may be mistaken for engine knock that first occurs as a cold start noise that fades as the engine reaches temperature; symptoms may also include increased emissions, poor acceleration, and engine idle speed surges