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Knocking noise from engine — rod bearing failure risk
Safe to Drive?
🚫 Do NOT Drive
Urgency Level
🔴 Fix Immediately
Estimated Repair Cost
GBP 8 – 1,400
A deep knocking or tapping noise from the engine that increases with RPM indicates possible connecting rod bearing failure. This is a serious and expensive fault — the bearing shells between the connecting rod and crankshaft journal have worn to the point where the rod is knocking against the crank. If the noise has just started, check the oil level immediately and perform an oil pressure test. Continued driving will cause the connecting rod to break through the engine block.
⚙️ Possible Causes
Possible: Hydraulic lifter knock — not rod bearingsPossible: Wasn't a rod knock — turned out to be a loose heat shieldPossible: Rod bearing knock — engine replaced, not rebuilt
Repair / Solution
Based on 351 driver confirmations
Hydraulic lifter knock — not rod bearings0%
0 worked · 0 did not· GBP 35 – 60· ⚪ Unverified🔧 Mechanic verified
Wasn't a rod knock — turned out to be a loose heat shield0%
0 worked · 0 did not· GBP 8 – 25· ⚪ Unverified🔧 Mechanic verified
Rod bearing knock — engine replaced, not rebuilt0%
0 worked · 0 did not· GBP 800 – 1,400· ⚪ Unverified🔧 Mechanic verified
🧾 Driver Reports
🟡 Partially FixedHydraulic lifter knock — not rod bearings
Knocking on cold start that reduced when warm. Thought it was bearings but oil pressure was fine. Mechanic said it was hydraulic lifters not pumping up properly — common on this engine with long oil change intervals. Fresh oil and a lifter flush treatment, knocking reduced massively. Full lifter replacement quoted at £380 if it gets worse.
Parts replaced: Engine oil flush, fresh oil and filter
💰 GBP 35 – 60🔧 Mechanic verified
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✅ FixedWasn't a rod knock — turned out to be a loose heat shield
Scary rattling knock from engine area. Convinced myself it was big end bearings. Mechanic put it on a ramp and found the exhaust heat shield had come loose and was rattling against the engine block. One bolt and a clamp, £25 labour. Felt very relieved.
Parts replaced: Heat shield clamp
💰 GBP 8 – 25🔧 Mechanic verified
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✅ FixedRod bearing knock — engine replaced, not rebuilt
Deep knocking from bottom of engine that got louder over 2 weeks. Mechanic confirmed rod bearing failure on cylinder 3. At 160k miles with that much labour the rebuild cost more than a replacement engine. Found a low mileage unit from a breaker for £400, fitted for £600. Running fine 15k miles later.