Serious engine failures rarely appear without warning. Symptoms — juddering, noises, starting difficulties — precede a major fault by hundreds, sometimes thousands of kilometres. Correctly interpreting these signals allows you to act in time and avoid costly repairs.
Starting problems
Engine does not turn over when starting
If you hear no starter motor action when turning the key, the most common cause is a flat battery, a faulty starter motor, or a break in the electrical circuit. Check whether other electrical consumers (lights, radio) are working normally. A weak or absent response points to the battery.
Starter motor turns slowly
Slow starter motor cranking with an audible relay click suggests a weak battery or worn starter brushes. Cold temperatures significantly reduce battery capacity — the problem may only appear in frost.
Starter motor cranks normally but engine does not fire
Normal cranking without the engine firing points to a problem with the ignition, fuel supply or compression. Check that there is sufficient fuel — a faulty fuel gauge is common on older vehicles.
Engine running
Engine starts but immediately stalls
The most common cause is a faulty MAF sensor, throttle position sensor, or a fuel supply problem — low fuel pressure or a blocked filter. On vehicles with an immobiliser, check the ECU-key communication.
Engine stalls while driving and will not restart
A sudden engine cut-out while driving with no restart usually points to fuel pump failure, a faulty crankshaft or camshaft sensor, or a break in the ECU power circuit. Computer diagnostics required.
Juddering and misfires while driving
Engine juddering is most commonly caused by worn spark plugs, faulty ignition coils or dirty injectors. Also check the air filter and fuel filter.
Cooling system
Correct operating temperature is crucial for long engine life. If the temperature gauge approaches the red zone, stop the vehicle and switch off the engine.
Warning: Never add cold water to the cooling system when the engine is hot. A sudden temperature change can crack the cylinder head or damage the head gasket — a much more serious and costly failure than the original cooling problem.
Signs of cooling system problems include: engine overheating, white smoke from the exhaust (possible head gasket failure), rapid coolant loss, or discoloured coolant.
Oil pressure
An oil pressure warning light illuminated while driving demands an immediate response. Continuing to drive without oil pressure can seize the engine within minutes.
Important distinction: A brief oil pressure warning at idle (especially when the engine is hot) can be normal in some engines due to reduced pressure at low revs. However, if the warning comes on during normal driving — stop the engine immediately and check the oil level.
Engine noises
Squealing or whistling
A squeal from the engine bay is most commonly a worn auxiliary belt or a failed alternator, tensioner or pulley bearing. Ignoring this can result in a snapped belt and cooling system damage (the water pump is belt-driven).
Knocking on cold start
Knocking for the first few seconds after a cold start may indicate worn valve guides or a problem with the variable valve timing system (VANOS, VVT). If the noise disappears once warm — monitor whether it worsens over time.
Tapping during engine operation
Regular tapping, especially increasing with engine speed, is a serious sign that may indicate worn crankshaft or connecting rod bearings. Urgent mechanical diagnosis required.
