Q: vanos solenoid bmw

The nature of the repair will have to do with the faults stored in the DME (engine computer). Spark plugs, though rated at 100K miles, have a service life of about 60K miles and should be replaced at tht mileage. BMW recommends replacement in the maintenance manual at 60K miles. The coils for the N52 engine have been improved over the years but have been a weak spot when it comes to long term performance. The VANOS solenoid which is responsible for camshaft adjustments are generally reliable on the N52 engine. The bulk of VANOS solenoid issues have been on the N55 turbo engines but this scenario is not completely out of the question. If you have VANOS system or camshaft position faults then the VANOS solenoid may be an issue. Again this repair should have system related faults pointing toward it. Also on the N52 engine there have been performance issues from both carbon build up on the back of the valves and also valvetronic actuator (variable valve lift system) issues. Carbon build up is corrected by having the valves cleaned. The valvetronic system either by an actuator replacement or eccentric shaft replacement. The first thing before replacing parts is to have fault codes read out to determine the path for diagnosis..