{"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":"ecoboost.coolant","aliases":[],"revision":1,"updatedAt":"2026-10-13","title":"Ford 1.0 EcoBoost (Fox) built October 2011 to October 2013: the degas pipe material can degrade, with coolant loss and overheating","summary":"In a November 2018 letter to the UK House of Commons Transport Committee, Ford stated that the degas pipe material on the 1.0L Fox engine could degrade, causing coolant loss and then overheating. Ford changed the material in production from October 2013 and ran voluntary service action 4S615 on just over 44,600 UK Focus with engines built October 2011 to October 2013. Ford said the DVSA did not classify it as a safety issue, and that overheating can lead to engine distortion and seizure. Ford also reported coolant leakage on Fiesta, B-MAX and C-MAX, and from October 2018 offered a 100% goodwill contribution to repair costs at Ford dealers for 1.0L Fox cooling issues.","checklistPrompt":"1.0 EcoBoost built 2011-2013: degas pipe - check it was replaced and the coolant level has been stable","component":"engine.cooling.hose","mechanism":"According to Ford's own evidence, the pipe in the cooling system (the degas pipe) of the early 1.0L Fox was made of a material that could degrade. The pipe then leaks coolant, the engine can overheat, and sustained overheating can distort the engine and lead to seizure. Ford changed the material in production from October 2013. Ford says it found no evidence of cylinder head cracking on this engine. The legacy wording of this item mentioned the cylinder head; cylinder head cracking belongs to the 1.6 Sigma engine, a different engine and a different defect, and is not part of this record.","applicability":{"models":[{"id":"ford.focus","label":"Ford Focus"},{"id":"ford.fiesta","label":"Ford Fiesta"},{"id":"ford.b_max","label":"Ford B-MAX"},{"id":"ford.c_max","label":"Ford C-MAX"}],"when":{"all":[{"engine":{"ids":["ford.fox_1_0"]}},{"productionDate":{"from":"2011-10","to":"2013-10"}}]},"markets":["UK"],"hint":"Only Ford 1.0 EcoBoost (Fox) engines built from October 2011 to October 2013. Ford's action covered the Focus; Ford says it also knows of coolant leakage on Fiesta, B-MAX and C-MAX 1.0L engines, so those are listed as likely rather than confirmed in scope.","notes":"Ford's figures are for UK cars. Whether the same action applied outside the UK was not checked."},"engines":[{"id":"ford.fox_1_0","family":"FOX","codes":["M1JA","M1JH","M1JL","M1JE","M1JJ","M1JU","SFJA","SFJB","SFJC","SFJD","M2DA","M2DC","M1DA","M1DC","M1DD","M1DH","M1CA","M1CB","YYJA","YYJB","YYJC","M0JB","B3DA","B7JB","B7JC","BZJA"],"fuel":"petrol","displacementCc":999,"powerKw":[],"label":"Ford 1.0 EcoBoost (Fox) turbo petrol"}],"gearboxes":[],"severity":"critical","safety":false,"critical":true,"evidenceGrade":"established","symptoms":[{"id":"s1","text":"Coolant level dropping, coolant smell or residue around the pipe","stage":"early"},{"id":"s2","text":"Engine temperature warnings","stage":"early"},{"id":"s3","text":"Overheating, engine distortion and seizure (Ford)","stage":"late"}],"inspection":[{"id":"i1","method":"document","text":"Check that the engine was built from October 2013 or that the degas pipe was replaced under Ford action 4S615 or later; ask for the invoice.","redFlag":"Engine built October 2011 to October 2013 with no record of the pipe.","tools":[]},{"id":"i2","method":"visual","text":"With the engine cold, check the coolant level and look for dried coolant around the degas pipe and expansion tank.","redFlag":"Low level, crusted residue or a recently topped-up system.","tools":[]},{"id":"i3","method":"obd","text":"Read the fault memory and watch the temperature gauge on a test drive.","redFlag":"Overheating warning or a temperature that climbs above normal.","tools":[]}],"repair":{"remedy":"Replacement of the degas pipe with the updated part; engine repair or replacement if overheating has already damaged it.","cost":null,"worstCase":null,"manufacturerProgramme":{"text":"Ford service action 4S615 (owner letters from April 2015, Non-Coded Action from mid-2017). From October 2018 Ford said it would make a 100% goodwill contribution to the cost of a repair at a Ford dealer for 1.0L Fox cooling issues, including engine replacement, and pay 100% of the cost of Ford parts at independent garages. These are UK terms stated in 2018; current eligibility was not checked.","evidence":["ev_pf_c01"]}},"evidence":["ev_pf_c01","ev_pf_c02"],"prevalence":["pv_pf_cl_fsa","pv_pf_cl_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_pf_c01","type":"manufacturer_statement","tier":1,"defects":["ecoboost.coolant"],"supports":["existence","mechanism","applicability"],"scope":{"all":[{"engine":{"ids":["ford.fox_1_0"]}},{"productionDate":{"from":"2011-10","to":"2013-10"}}]},"source":{"publisher":"Ford of Britain, published by the UK House of Commons Transport Committee","title":"Correspondence from Ford of Britain to the Chair of the Transport Committee on 1.0L EcoBoost (Fox) and 1.6L EcoBoost (Sigma) engines, 13 November 2018","url":"https://committees-api.parliament.uk/api/Publications/18188","identifier":"UK Parliament committee publication 18188","publishedDate":"2018-11-20","retrievedAt":"2026-10-13","language":"en","archive":null,"license":"proprietary","reuse":"cite","status":"no_archive"},"quote":null,"translation":null,"note":"Ford of Britain's letter to the Transport Committee (dated 13 November 2018, published 20 November 2018): the degas pipe material on the 1.0L Fox engine in the Focus could degrade, causing coolant loss and then overheating. Ford upgraded the pipe material in production from October 2013 and ran voluntary field service action 4S615 (owner letters from April 2015) on just over 44,600 UK Focus with engines built October 2011 to October 2013, 90.3% reworked at the time, upgraded to a Non-Coded Action in mid-2017. Ford says the DVSA did not classify it as a safety issue. Ford says it is aware of coolant leakage on Fiesta, B-MAX and C-MAX 1.0L Fox vehicles, that coolant loss can lead to engine distortion and seizure, that there is no evidence of cylinder head cracking on this engine, and that it knows of no proven cooling-system fires. From October 2018 Ford makes a 100% goodwill contribution to repair costs at Ford dealers for 1.0L Fox cooling issues. The publication record is linked; the letter itself was read from an Internet Archive copy (captured 2023-06-15) because the parliament.uk file is behind a bot challenge.","confidence":"high","reviewedAt":"2026-10-13","reviewStatus":"source_verified"},{"id":"ev_pf_c02","type":"specialist_press","tier":2,"defects":["ecoboost.coolant"],"supports":["existence","mechanism","applicability"],"scope":{"all":[{"engine":{"ids":["ford.fox_1_0"]}},{"productionDate":{"from":"2011-10","to":"2013-10"}}]},"source":{"publisher":"Autocar","title":"Ford to cover costs of repairing 1.0 EcoBoost engines","url":"https://www.autocar.co.uk/car-news/new-cars/ford-ecoboost-engine-failures-customers-receive-refunds","identifier":null,"publishedDate":"2018-10-01","retrievedAt":"2026-10-13","language":"en","archive":{"url":"https://web.archive.org/web/20250209160902/https://www.autocar.co.uk/car-news/new-cars/ford-ecoboost-engine-failures-customers-receive-refunds","capturedAt":"2025-02-09","sha256":null},"license":"proprietary","reuse":"cite","status":"archived"},"quote":null,"translation":null,"note":"UK motoring magazine: reports 44,682 cars with build dates October 2011 to October 2013, a service action in March 2015, 96% reworked, and quotes Ford's statement on the repair cost contribution.","confidence":"medium","reviewedAt":"2026-10-13","reviewStatus":"source_verified"}],"prevalence":[{"id":"pv_pf_cl_fsa","kind":"recall_scope","value":44600,"unit":"units","numerator":null,"denominator":null,"ci":null,"population":{"description":"UK Focus with 1.0L engines built October 2011 to October 2013 in Ford voluntary action 4S615 (just over 44,600 cars)","applicability":null,"geography":"UK","period":null,"ageYears":null},"outcome":"Vehicles in the service action","baseline":null,"method":null,"evidence":["ev_pf_c01"],"confidence":"C","caveats":["A voluntary non-safety service action, not a recall. The count is vehicles in scope, not vehicles that failed; Fiesta, B-MAX and C-MAX are not in the figure."],"noReliableFigure":false,"reason":null},{"id":"pv_pf_cl_none","kind":"none","value":null,"unit":null,"numerator":null,"denominator":null,"ci":null,"population":null,"outcome":null,"baseline":null,"method":null,"evidence":["ev_pf_c01"],"confidence":null,"caveats":[],"noReliableFigure":true,"reason":"No verified share of affected engines that lost coolant or overheated has been published. Ford gives the size of the service action and the share already reworked, not a failure rate."}],"attributions":[]}