{"canonVersion":{"checklist":1,"defects":2},"defectsRelease":{"format":3,"release":"2026.10.1","dossiers":15},"attribution":{"source":"Elgarde","url":"https://elgarde.com","license":"CC-BY-4.0","repository":"https://github.com/ElgardeCom/elgarde"},"disclaimer":"Elgarde is a self-service checklist, not a certified, mechanical or legal inspection and not professional advice. Defect entries are known weak points to check on a model — never a claim about any individual car.","defectsDisclaimer":"Each entry describes a known weak point of a model, engine or gearbox, based on published sources. It is not a statement about any individual car and not a diagnosis. An entry does not mean that a given car has the defect; the absence of an entry does not mean that a car is sound. Prevalence figures are estimates for the stated population and method, with their biases, and cannot be applied to a single car. The data is provided as is, without warranty (CC-BY-4.0, section 5); it is not a certified, mechanical or legal inspection. Naming a manufacturer or its product is not an assessment of that manufacturer; source links show where each fact comes from. To report an error, open an issue at github.com/ElgardeCom/elgarde or write to support@elgarde.com. We correct mistakes.","lang":"en","defect":{"id":"oil.leaks","aliases":[],"revision":1,"updatedAt":"2026-10-13","title":"BMW N20 and N55 petrol engines (August 2011 to March 2012 builds): plastic oil filter housing oil or coolant leak","summary":"BMW issued service actions in 2015 for N20 and N55 engines built from August 2011 to March 2012: the plastic oil filter housing may fail and lead to an internal and/or external engine oil or coolant leak. Dealers inspect the housing and replace it if it is the plastic (black) type; the aluminium (silver) type needs no action. The earlier checklist item also named valve cover gaskets; no usable source was found for that and it is not covered here.","checklistPrompt":"N20/N55 petrol, built Aug 2011 - Mar 2012: oil filter housing — plastic (black) or aluminium (silver)? BMW service action","component":"engine.lubrication.oil_filter_housing","mechanism":"According to BMW's service actions, the plastic oil filter housing fitted to N20 and N55 engines in the stated builds may fail and lead to an internal and/or external leak of engine oil or coolant. BMW's remedy is to replace the plastic (black) housing with a new one; cars already fitted with the aluminium (silver) housing need no action. The BMW documents give no cause for the failure.","applicability":{"models":[{"id":"bmw.x1","label":"BMW X1"},{"id":"bmw.z4","label":"BMW Z4"},{"id":"bmw.5series","label":"BMW 5 Series"},{"id":"bmw.x3","label":"BMW X3"},{"id":"bmw.3series","label":"BMW 3 Series"}],"when":{"any":[{"all":[{"productionDate":{"from":"2011-08","to":"2012-03"}},{"any":[{"engine":{"ids":["bmw.n20"]}},{"all":[{"engine":{"ids":["bmw.n55"]}},{"model":["bmw.3series"]}]}]}]},{"all":[{"engine":{"ids":["bmw.n55"]}},{"productionDate":{"from":"2011-08","to":"2012-01"}}]}]},"markets":["US"],"hint":"BMW cars with the N20 engine (E84 X1, E89 Z4, F10 5 Series, F25 X3, F30 3 Series) or the N55 engine in the F30 3 Series built from August 2011 to March 2012, and other N55 cars of these series built from August 2011 to January 2012, and only if the oil filter housing is the black plastic type. Other BMW engines and other build dates are not covered.","notes":"The BMW bulletins are US service documents (BMW of North America); whether the same housings were fitted to European-market cars is not stated in them. BMW's N55 service action names only the F30; a separate BMW information bulletin lists the black plastic housing on N20 and N55 engines in E84, E89, F10, F10H, F25 and F30 cars built from August 2011 to January 2012, so other N55 cars of those builds are included as possible: check the housing colour. The N20 action lists labour operations for inspection only (aluminium) and for replacement (plastic). No failure rate or repair cost is published in the sources used here."},"engines":[{"id":"bmw.n20","family":"N20","codes":["N20"],"fuel":"petrol","displacementCc":null,"powerKw":[],"label":"BMW N20 petrol"},{"id":"bmw.n55","family":"N55","codes":["N55"],"fuel":"petrol","displacementCc":null,"powerKw":[],"label":"BMW N55 inline-six petrol"}],"gearboxes":[],"severity":"moderate","safety":false,"critical":false,"evidenceGrade":"established","symptoms":[{"id":"s1","text":"Engine oil or coolant leaking at the oil filter housing","stage":"early"},{"id":"s2","text":"Internal leak of engine oil or coolant","stage":"late"}],"inspection":[{"id":"i1","method":"document","text":"Confirm the engine (N20, or N55) and the build date (door-pillar label or dealer VIN query): August 2011 to March 2012 for the N20 and the N55 in an F30, August 2011 to January 2012 for other N55 cars.","redFlag":"Engine and build date in range.","tools":[]},{"id":"i2","method":"visual","text":"Look at the oil filter housing: black plastic is the type BMW's service action replaces; silver aluminium needs no action. Look around it for oil or coolant residue.","redFlag":"Black plastic housing, or oil or coolant residue around it.","tools":[]},{"id":"i3","method":"document","text":"Ask for invoices showing the oil filter housing was inspected or replaced under BMW's service action (SI B11 13 15 for N20, SI B11 14 15 for N55).","redFlag":"Plastic housing in the build window and no record of the action.","tools":[]}],"repair":{"remedy":"Replacement of the plastic oil filter housing (with the related seals and coolant hoses listed in the BMW bulletin) on cars that have the black plastic type; no action for the aluminium type.","cost":null,"worstCase":null,"manufacturerProgramme":{"text":"BMW service actions SI B11 13 15 (N20) and SI B11 14 15 (N55), 2015: dealers inspect the housing and replace the plastic (black) type. The bulletins give dealer reimbursement labour operations but do not state the terms for owners.","evidence":["ev_bmmb_e07","ev_bmmb_e08"]}},"evidence":["ev_bmmb_e07","ev_bmmb_e08","ev_bmmb_e09"],"prevalence":["pv_oil_none"],"disclaimer":"Each entry describes a known weak point of a model, engine or gearbox, based on published sources. It is not a statement about any individual car and not a diagnosis. An entry does not mean that a given car has the defect; the absence of an entry does not mean that a car is sound. Prevalence figures are estimates for the stated population and method, with their biases, and cannot be applied to a single car. The data is provided as is, without warranty (CC-BY-4.0, section 5); it is not a certified, mechanical or legal inspection. Naming a manufacturer or its product is not an assessment of that manufacturer; source links show where each fact comes from. To report an error, open an issue at github.com/ElgardeCom/elgarde or write to support@elgarde.com. We correct mistakes."},"evidence":[{"id":"ev_bmmb_e07","type":"tsb","tier":1,"defects":["oil.leaks"],"supports":["existence","mechanism","applicability","remedy","manufacturer_acknowledgement"],"scope":{"all":[{"engine":{"ids":["bmw.n20"]}},{"productionDate":{"from":"2011-08","to":"2012-03"}}]},"source":{"publisher":"BMW of North America (hosted by NHTSA)","title":"SI B11 13 15 - Service Action: N20 Engine - Inspect and Replace Engine Oil Filter Housing (August 2015 revision)","url":"https://static.nhtsa.gov/odi/tsbs/2015/MC-10151399-9999.pdf","identifier":"SI B11 13 15","publishedDate":"2015-08","retrievedAt":"2026-10-13","language":"en","archive":{"url":"https://web.archive.org/web/20261013104930/https://static.nhtsa.gov/odi/tsbs/2015/MC-10151399-9999.pdf","capturedAt":"2026-10-13","sha256":null},"license":"proprietary","reuse":"cite","status":"archived"},"quote":null,"translation":null,"note":"BMW service action: the plastic oil filter housing may fail and lead to an internal and/or external engine oil or coolant leak. Applies to E84, E89, F10, F25 and F30 with the N20 engine produced August 2011 to March 2012. Procedure: inspect; if the housing is aluminium (silver) take no action; if plastic (black), replace the housing.","confidence":"high","reviewedAt":"2026-10-13","reviewStatus":"source_verified"},{"id":"ev_bmmb_e08","type":"tsb","tier":1,"defects":["oil.leaks"],"supports":["existence","mechanism","applicability","remedy","manufacturer_acknowledgement"],"scope":{"all":[{"engine":{"ids":["bmw.n55"]}},{"model":["bmw.3series"]},{"productionDate":{"from":"2011-08","to":"2012-03"}}]},"source":{"publisher":"BMW of North America (hosted by NHTSA)","title":"SI B11 14 15 - Service Action: N55 Engine - Inspect and Replace Engine Oil Filter Housing","url":"https://static.nhtsa.gov/odi/tsbs/2016/MC-10150903-9999.pdf","identifier":"SI B11 14 15","publishedDate":"2015-10","retrievedAt":"2026-10-13","language":"en","archive":{"url":"https://web.archive.org/web/20261013105002/https://static.nhtsa.gov/odi/tsbs/2016/MC-10150903-9999.pdf","capturedAt":"2026-10-13","sha256":null},"license":"proprietary","reuse":"cite","status":"archived"},"quote":null,"translation":null,"note":"BMW service action for the N55 engine with the same wording: the plastic oil filter housing may fail and lead to an internal and/or external engine oil or coolant leak. Applies to the F30 (3 Series sedan) produced August 2011 to March 2012; aluminium (silver) housing: no action; plastic (black) housing: replace.","confidence":"high","reviewedAt":"2026-10-13","reviewStatus":"source_verified"},{"id":"ev_bmmb_e09","type":"tsb","tier":1,"defects":["oil.leaks"],"supports":["applicability"],"scope":{"productionDate":{"from":"2011-08","to":"2012-01"}},"source":{"publisher":"BMW of North America (hosted by NHTSA)","title":"SI B11 05 15 - N20 and N55 Engine: Engine Oil Filter Application for Plastic Oil Filter Housing","url":"https://static.nhtsa.gov/odi/tsbs/2015/MC-10147653-9999.pdf","identifier":"SI B11 05 15","publishedDate":"2015-03","retrievedAt":"2026-10-13","language":"en","archive":{"url":"https://web.archive.org/web/20261013105140/https://static.nhtsa.gov/odi/tsbs/2015/MC-10147653-9999.pdf","capturedAt":"2026-10-13","sha256":null},"license":"proprietary","reuse":"cite","status":"archived"},"quote":null,"translation":null,"note":"BMW information bulletin: N20 and N55 engines in E84, E89, F10, F25 and F30 produced August 2011 to January 2012 were built with a black plastic oil filter housing; it lists the matching oil filter part numbers. Confirms that the plastic housing exists on both engines in those builds.","confidence":"high","reviewedAt":"2026-10-13","reviewStatus":"source_verified"}],"prevalence":[{"id":"pv_oil_none","kind":"none","value":null,"unit":null,"numerator":null,"denominator":null,"ci":null,"population":null,"outcome":null,"baseline":null,"method":null,"evidence":["ev_bmmb_e07","ev_bmmb_e08"],"confidence":null,"caveats":[],"noReliableFigure":true,"reason":"No verified share of the covered N20 and N55 engines with a failed plastic oil filter housing has been published, and the BMW service actions do not state how many cars they cover."}],"attributions":[]}