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Greetings,

2012 MINI Cooper D R57 (N47 engine) with about 108,000 kilometres.

Replaced the upper timing chain and tensioner in situ following a local independent's diagnosis of startup rattling, while I identified subpar performance and a pronounced diesel odour. The chain had actually elongated and skipped many teeth, though not sufficiently to inflict any lasting damage on other components. These engines exhibit considerable resilience. The rocker cover gasket was changed; however, a slight oil leak persists. The rocker cover is suspected to have a fracture.

The timing has likely been misaligned for some time, which probably accounts for the excessive soot in this engine.

I am fairly certain that three out of four, if not all, glow plugs are nonfunctional, and I also suspect that the glow plug control module may be malfunctioning.

4A64: Activation of glow plug for cylinder 1 4A54: Activation of glow plug for cylinder 2 4A44: Activation of glow plug for cylinder 3 4A34: Control of glow plug for cylinder 4

I am preparing to repair all four glow plugs, but I am not anticipating that day with enthusiasm; I will also replace the control module if the plugs are in satisfactory condition.

The primary concern at now is the recurrence of three chronic EGR faults.

40A4: Long-term deviation in the exhaust gas recirculation location
40D4: Position control for exhaust gas recirculation at position 40D4
4C9E: 4C9E exhaust gas recirculation location, validity

The vehicle appears to be lacking in power and does not idle as smoothly as I would prefer. The DPF appears to be regenerating adequately (verified via Bimmerlink), despite not having heard the cooling fan operate after engine shutdown for several weeks.

Do you have any insights into the potential issues with the EGR valve? I assume it is entirely saturated with soot, but I seek more perspectives before proceeding with a replacement, if necessary.

I possess a moderate proficiency with a socket set; nonetheless, I am uncertain if this task exceeds my DIY skills, as I anticipate encountering seized bolts that may fracture upon application of a socket.

Thank you, everybody!

I will consult our engine expert.

I suspect that the EGR and DPF are obstructed, if I were to conjecture.

I suspect the EGR is likely malfunctioning, however I am less certain regarding the DPF. The DPF appears to be regenerating normally, having successfully performed a regeneration within the last 5 kilometres. According to Bimmertool, the DPF contains 15.89g of soot and approximately 41.32g of ash. I believe this is acceptable within the specified limits.

I anticipate that @jane_doe2023 will recommend the removal of the EGR and DPF, which I concur is optimal for these engines, however unlawful.

Alternative options, such as replacing the EGR, will be evaluated.

The BMW DPF filter was quoted at £1650, the EGR valve at an additional £500 if available, although they lack sufficient stock for all recalled vehicles. The control module from BMW is priced at £57. Best of luck with the glow plugs. Diesel particulate filters (DPF) typically have a lifespan of approximately 80,000 to 100,000 miles. In engines experiencing glow plug failure, the DPF will not regenerate, leading to significant clogging that prevents successful regeneration. You are correct that this practice is illegal; however, currently, it is merely a visual inspection, and if conducted properly, it remains undetectable. Continuing to operate the vehicle in this manner will inevitably resu

Glow plugs often fracture during removal. If operating a diesel particulate filter (DPF), functional glow plugs are essential for regeneration. However, if the exhaust gas recirculation (EGR) and DPF are deactivated, they are unnecessary. This may incur an additional cost of £500 to £1000 for cylinder head removal.

At a certain juncture, the expenses associated with emissions-related repairs or replacements become prohibitive, rendering the removal of the DPF and EGR more appealing (until one incurs fines and must either reinstate the components or dispose of the vehicle). I anticipate that emissions testing will grow increasingly rigorous over time, and MOT inspectors will gain the capacity to investigate more thoroughly than permitted currently.

I will not be replacing the DPF, and the EGR valve does not appear to have entirely broken; it is merely generating a few error codes that do not currently trigger a check engine light on the dashboard. For the time being, the most prudent course of action for this vehicle is to diligently do routine maintenance, increase the frequency of oil changes, monitor the DPF soot and ash mass using Bimmerlink, and refrain from tampering with the glow plugs until the DPF fails entirely.

While I acknowledge that functional glow plugs are necessary to elevate exhaust gas temperature for enhanced soot combustion, my experience indicates that they do not inhibit the DPF from initiating or successfully completing a regeneration cycle. Its efficacy will diminish, and I anticipate an increase in unburnt diesel contaminating the oil as a consequence; yet, I am amenable to changing the oil every 9,000 miles, provided the vehicle endures that duration.

It has successfully passed the MOT for the eleventh straight year, with only one failure in 2021 due to leaking shocks. The car has minimal value and has incurred only routine maintenance costs, including shocks and the upper timing chain, over the 11 years of ownership.

We will continue to operate it until repair costs become prohibitive. At that juncture, it is appropriate to substitute it with an F56 JCW.