Problems with the big-end bearings and pistons: symptoms, cost and affected models
We have documented 12 faults with the big-end bearings and pistons in 11 engines, affecting 94 models of car in our database. The most important by severity and frequency: wear and seizure of the big-end bearings (1.5 dCi), seizure and wear of the big-end bearings (1.9 dCi) and bearing wear and crankshaft failure on the EE20 diesel (Subaru bóxer).
How it works and why it fails
Big-end bearings and pistons
Big-end bearings let the connecting rods turn on the crankshaft on a film of oil. If that film fails (degraded oil, low level or a marginal design), they wear, knock and can seize the engine. Pistons and rings, for their part, can crack or stick with carbon.
What to do
A heavy metallic knock that increases with revs or the oil pressure warning light are reasons to stop the engine immediately. Change the oil to the correct specification without stretching the intervals, especially on diesels with a particulate filter.
General explanation by MotorFiable. The specific faults of each engine and car, with their sources, are on the linked pages.
Common symptoms
The symptoms that come up most often in the documented faults with the big-end bearings and pistons. Open each one to see what other faults cause it.
Problems with the big-end bearings and pistons by engine
From most to least important (severity × frequency). Each page details the affected versions and years, symptoms, cost and how to check for it.
- 1Critical severityCommonFrequency: Common1.5 dCiWear and seizure of the big-end bearingsThe Euro 3 and Euro 4 1.5 dCi engines (approx. 2001-2010), especially the 100 and 105/106 hp, have fragile big-end bearings that can seize and wreck the engine. Renault went as far as paying up to 90% of the repair, with a limit of 7 years and 180,000 km.
- 2Critical severityCommonFrequency: Common1.9 dCiSeizure and wear of the big-end bearingsOn the 95 to 120 hp versions built before 2005, the big-end bearings of the 1.9 dCi (F9Q) are fragile and can seize, which wrecks the bottom end of the engine. Renault did not acknowledge an official campaign, but it resolved some out-of-warranty cases.
- 3Critical severityCommonFrequency: CommonSubaru bóxerBearing wear and crankshaft failure on the EE20 dieselOn the first EE20 boxer diesels (Legacy and Outback built from autumn 2007 to February 2009; Impreza 2007-2009) the crankshaft bearings could fail and break the crankshaft, destroying the engine. AUTO BILD cites two causes: silicone in the sump and bearings with incorrect clearance.Appears at around 65,000 km
- 4Critical severityCommonFrequency: Common1.9 TDIBig-end bearing failureOn the unit injector, above all in the 105 hp version, there are several documented cases of big-end bearings that wear and break, destroying the engine, with no manufacturer campaign or official incidence figure.Appears at around 138,000 km
- 5Critical severityOccasionalFrequency: Occasional1.6 GDI / T-GDILow-speed pre-ignition and connecting rod damage in the 1.6 T-GDI (documented in the US)In the US, Hyundai and Kia have recalled the 1.6 T-GDI (Veloster, Forte): an engine software fault can allow pre-ignition that damages connecting rods and pistons, with knocking complaints after the update. No equivalent pattern documented for the same engine in Europe.Appears at around 100,000 km
- 6Critical severityOccasionalFrequency: Occasional2.0 / 2.4 GDI and T-GDI (Theta II)Premature connecting rod bearing wearThe connecting rod bearings can wear prematurely and end up stopping the engine. It is the defect behind Hyundai and Kia's big US campaigns; in Europe, since 2023 Kia has been inspecting 2011-2015 Sorento XM 2.4 MPI (and other models) for this reason.
- 7Critical severityOccasionalFrequency: OccasionalTDV6 / SDV6Crankshaft breakage and spinning main bearing shellsOn the TDV6/SDV6 in the Discovery 3 and 4, Range Rover and Range Rover Sport, crankshaft failures have been documented caused by main bearing shells that are badly seated or that spin; the engine can seize and needs replacing or rebuilding.
- 8Critical severityOccasionalFrequency: OccasionalMZR gasolinaBig-end bearing damage in the 2.3 MZR, with isolated cases in the 1.8 and 2.0Gebrauchtwagenberater.de cites big-end bearing damage as a known weak point of the 2.3 MZR of the Mazda6 GG, and fiches-auto.fr adds two isolated cases: a Mazda6 1.8 with a blown engine and a Mazda3 2.0 with a damaged big-end bearing at around 50,000 km.
- 9Critical severityOccasionalFrequency: Occasional1.4 TurboEarly engine failure from a cracked pistonOn the Astra K, Adam and Zafira Tourer with this engine there are several documented cases of complete engine failure, on the Astra K from as little as 13,000-20,000 km and with a piston crack confirmed by the garage in at least one case; there is no manufacturer campaign or overall fleet figures.Appears at around 13,000 km
- 10Critical severityRareFrequency: RareBMW B38 / B37B38 crankshaft thrust bearing failure (units before April 2015)The first units of the 136 hp 1.5 (up to April 2015) had a half-wedge crankshaft thrust bearing that failed in two long-term tests at about 100,000 km with heavy clutch use; BMW changed it to a 360-degree one.Appears at around 100,000 km
- 11Critical severityRareFrequency: Rare1.6 GDI / T-GDIPiston and connecting rod damage from catalytic converter overheating in the naturally aspirated 1.6 GDIIn the US, Kia recalled the 2012-2016 Soul with the naturally aspirated 1.6 GDI: a catalytic converter that overheats can disturb combustion and damage pistons, with a risk of breaking a connecting rod and puncturing the block. We have not found an equivalent warning for this engine in European cars.
- 12High severityRareFrequency: Rare1.2 PureTechFaulty piston cooling jets (naturally aspirated, 2022-2024)Stellantis recalled in France about 68,000 Peugeot 208, Citroën C3 and Opel Corsa models from 2022-2024 with the naturally aspirated PureTech because of faulty piston cooling jets: they cause noise and, in extreme cases, damage to the engine casing and oil on the exhaust. It is fixed with an oil and filter change.Repair: €0
Engines with faults with the big-end bearings and pistons
Problems with the big-end bearings and pistons by make
Problems with the big-end bearings and pistons in your car
7 cars have several documented faults with the big-end bearings and pistons. Choose yours to see only the ones that affect them, by engine and by year.
How much it costs to repair a fault with the big-end bearings and pistons
Sorted from the most expensive repair to the cheapest. Prices in Spain including VAT (parts and labour); what each figure includes is on its page.
- Garage
- No data
- Dealer
- €0
- Published figure[1]
How we calculate costs · The most expensive repairs across all engines
OBD fault codes with the big-end bearings and pistons
The codes the ECU usually stores when this part fails: what they mean, causes and what to check.
Frequently asked questions
Which engines have the most faults with the big-end bearings and pistons?
By severity and frequency, the 1.5 dCi (wear and seizure of the big-end bearings, critical severity), the 1.9 dCi (seizure and wear of the big-end bearings, critical severity), the Subaru bóxer (bearing wear and crankshaft failure on the EE20 diesel, critical severity), the 1.9 TDI (big-end bearing failure, critical severity), the 1.6 GDI / T-GDI (low-speed pre-ignition and connecting rod damage in the 1.6 T-GDI (documented in the US), critical severity) and the 2.0 / 2.4 GDI and T-GDI (Theta II) (premature connecting rod bearing wear, critical severity). In total we have documented 11 engines with faults with the big-end bearings and pistons.
How much does it cost to repair a fault with the big-end bearings and pistons?
It depends a lot on the engine or car. At a dealer, from €0 to €0, including VAT, based on the 1 fault with a documented cost. The most expensive is faulty piston cooling jets (naturally aspirated, 2022-2024) (1.2 PureTech).
What symptoms does a fault with the big-end bearings and pistons cause?
The most frequently cited in the documented faults: deep metallic engine knock, engine stalls or cuts out while driving, oil pressure warning light on, engine fault warning light (check engine), excessive oil consumption and visible oil leak.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- 1.Automaker Stellantis recalls 68,000 units in France due to fire riskEuronews · General press · published 25 February 2025 · consulted 26 September 2026