The M47N engine in the E46 320d is a popular choice in the UK for its torque and potential economy. However, it's not without its well-documented weak spots, particularly swirl flaps and turbocharger issues. This thread is for UK owners to share experiences, preventative measures, and repair advice.
Let's Discuss Key M47N Topics:
- Swirl Flaps: The big one! Have you had them removed/blanked? If so, which kit did you use (UK suppliers)? Did you notice any performance difference? If you've kept them, what's your maintenance or inspection routine? Any horror stories of ingestion?
- Turbocharger Failures: Symptoms of a failing turbo on the M47N (e.g., smoke, whining, loss of power)? What are the common causes (e.g., blocked breather, oil starvation)? Experiences with OEM vs. aftermarket replacement turbos in the UK? Costs involved?
- Crankcase Breather (Oil Separator): The importance of changing the "loo roll" filter to the vortex style, or regular replacement of the filter type. How often do you change yours?
- Injectors: Common injector problems, symptoms, and cleaning/replacement advice.
- Thermostats (Main & EGR): Issues with these sticking open, leading to poor MPG and DPF issues (if applicable on later non-E46 models, but good habit).
- Glow Plugs & Controller: Common starting issues in UK winters?
- Preventative Maintenance: What specific preventative measures do you take with your M47N 320d to ensure longevity in UK conditions? (e.g., oil change intervals, specific oils, fuel treatments).
Let's help each other keep these torquey diesels running strong!
