BMW M135i: Common Problems & Reliability Guide (South Africa)
Also covers: M140i
These are issues documented for the BMW M135i in general - things to check for, not a diagnosis of any particular car. Whether a specific car has one depends on its age, mileage, service history and how it was used.
Free Vehicle Check
Looking at one of these for sale? Check the exact vehicle free.
Enter the listing or vehicle details and AutoLytiQs will compare its price, specification and documented risks.
Check This Vehicle Free →N55 VANOS Solenoid Clogging / Gear-Assembly Bolt Wear (M135i) & B58 Valve Cover/PCV, Coolant System and HPFP Wear Items (M140i)
Symptoms to watch for
- N55 (M135i): rattling noise from the engine compartment, a genuine loss of power, and the Service Engine Soon light - BMW's own TSB-stated symptom set
- N55 (M135i): rough idle, drivability issues, or a loud squealing noise if the PCV diaphragm (integrated into the valve cover on this engine, per bmwtuning.co) has torn
- M140i (B58, wear items, per a related documented issue): burning oil smell, oil staining around the engine's top, oily spark-plug wells (valve cover/PCV); coolant residue at the water pump weep hole, slow coolant loss, temperature warnings (coolant system); power loss, rough cold idle, increased fuel consumption (VANOS); worsening rough idle, hesitation, possible misfire (carbon buildup); long cranking especially in cold weather, misfires, stalling/limp mode (HPFP)
Rough Repair Cost
Independent workshops typically charge R2 700-R8 500 for this, depending on exactly what's needed. The full independent-vs-dealer breakdown is in a full AutoLytiQs report.
What To Check
M135i (N55): per a related documented issue, the TSB's own stated symptoms (rattling, loss of power, warning light) should be noticeable on a normal test drive once advanced enough to log fault codes; earlier solenoid-tier issues may only show as rough idle or hesitation. M140i (B58): per a related documented issue, wear items are partially detectable on a longer test drive (rough idle, cold-start behaviour, visible smoke, oil smell, coolant warnings) but early-stage wear may not be obvious on a short test - a specialist pre-purchase inspection covering these specific items is materially more reliable than driving impressions alone, and this card cannot confirm the same reliability for the M140i's earlier, less-documented engine revision specifically.
Check a specific real listing for this vehicle and see the evidence behind every documented issue - one report, only R69, once:
- Repair-cost estimate for 1 of 1 documented issue
- Specific fault code to scan for
- 1 verified manufacturer TSB/recall reference you can check yourself
- A recommended fix or negotiation point for that issue
- A downloadable PDF report
No subscription · One-time payment · Instant access
Already found one elsewhere? Enter its details manually instead.
This guide summarises documented, sourced findings for the BMW M135i generally. It is not an assessment of any specific vehicle - mileage, service history and condition vary by example. A full AutoLytiQs™ report checks a specific listing for sale against this data plus a live South African market valuation, to tell you whether that exact vehicle is a good buy.