Valve seals – identified by smoking once the car is warmed up and has been idling for a while; can be replaced without removing the heads, but still not cheap
Valve cover diaphragms
Upper timing cover gaskets – if there is a small coolant leak coming from the timing cover, expect up to 60 hours of labor to fix it (however, there are third-party solutions involving a new coolant pipe which are <10 hours)
Alternator bracket gaskets
Alternator oil seal
TSB – Oil pump check valve
Oil Separator Valve (OSV) / Crank Case Ventilation (CCV) – symptoms are high oil consumption, poor running, and sometimes a whistling noise; it’s located under the throttle body, 4-8 hours of labor to replace it. This is often caused by a lot of short drives. Sometimes, it can be fixed by a lot of long drives and high revs.
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
Certain Vehicles
MY04-05: TSB – Faulty Valvetronic intermediate levers may cause erratic or variable idle speed for around 20 seconds after cold start, CEL, and/or misfire fault codes
