Slow cranking or just a click, worse when the engine is warm
2009 · Skoda Fabia II · 1.4 16V · 160,000 km
No fault codes
Root cause: Corroded engine ground strap with high resistance, worse when hot.
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Repair cases shared by mechanics and reviewed before publishing. Hide the solutions to diagnose them yourself first. Cases marked "Training case" are written by ipacen from typical faults for practice.
Flat battery after two days parked
2008 · Opel Astra H · 1.6 16V · 175,000 km
No fault codes
Root cause: Glovebox light switch stuck closed, keeping the lamp on with the lid shut.
Black smoke, rough idle and limp mode in town traffic
2010 · Fiat Punto Evo · 1.3 Multijet 75 · 150,000 km
P0404
Root cause: EGR valve sticking partly open with carbon from short trips.
Losing coolant with no visible leak and bubbles in the tank
2008 · Toyota Avensis (T25) · 2.2 D-4D (2AD-FTV) · 205,000 km
No fault codes
Root cause: Head gasket failure at cylinder 3, caused by oil consumption and carbon build-up; the aluminium block deck was no longer flat.
Limp mode when loaded on hills, whoosh under boost
2013 · Mercedes-Benz Sprinter 316 CDI · 2.1 CDI (OM651) · 262,000 km
P0299
Root cause: Charge-air hose split on the inside of a bend, softened by oil vapour.
Whistle at idle, slightly rough idle and a lean code
2012 · Volkswagen Passat B7 · 1.8 TSI (CDAB) · 136,000 km
P0171
Root cause: Split diaphragm in the crankcase breather (PCV) valve, letting in unmetered air and losing crankcase pressure control.
Rattle for two seconds on a cold start, then a warning light
2011 · Volkswagen Polo V · 1.2 TSI (CBZB) · 88,000 km
P0016
Root cause: Timing chain stretched and its guide worn, so the tensioner could no longer take up the slack on cold starts.
Oil pressure warning at hot idle and a hard brake pedal
2016 · Peugeot 208 · 1.2 PureTech 110 · 112,000 km
P0524
Root cause: The timing belt that runs in the oil had degraded; belt particles blocked the oil pickup strainer and the brake vacuum pump oil feed.
Temperature warning and reduced power on the motorway
2014 · Ford Focus Mk3 · 1.0 EcoBoost 125 · 98,000 km
P0217
Root cause: Split degas (expansion tank) hose leaking coolant until the engine overheated.
Particulate filter light, limp mode and oil level rising
2015 · Dacia Duster · 1.5 dCi 110 (K9K) · 120,000 km
P2463P0128
Root cause: Thermostat stuck partly open: the engine never got warm enough to finish a regeneration, so the filter loaded up and fuel from the interrupted regenerations diluted the oil.
Rattle from the back of the engine at warm idle
2009 · BMW 320d (E90) · 2.0d (N47) · 189,000 km
No fault codes
Root cause: Timing chain stretched with a cracked guide rail at the rear of the engine.
Siren noise under boost, blue smoke and loss of power
2009 · Peugeot 308 · 1.6 HDi 110 (9HZ) · 165,000 km
P0299
Root cause: Turbo bearings failed from oil starvation: carbon from a leaking injector washer got into the oil and blocked the turbo oil feed filter and the sump strainer.
Deep knock from the bottom end and oil light at hot idle
2012 · Renault Megane III · 1.5 dCi (K9K) · 196,000 km
No fault codes
Root cause: Big-end bearing on cylinder 2 spun after long oil intervals with oil diluted by diesel from interrupted particulate filter regenerations.
Engine warning light on, but the car drives normally
2011 · Skoda Octavia II · 2.0 TDI CR (CFHC) · 214,000 km
P2015
Root cause: Broken plastic ball joint in the intake manifold flap linkage.
Long crank when warm and white smoke for a few seconds
2011 · Volkswagen Golf VI · 1.6 TDI (CAYC) · 178,000 km
P0266
Root cause: Injector no. 2 worn internally: too much leak-back while running and dripping into the cylinder after shut-off.