What Causes the Timing Chain Noise in Geely Emgrand?
4 Answers
There are two main reasons for the timing chain noise in Geely Emgrand: one is timing chain wear, and the other is tensioner failure. Timing chain wear: The timing chain of the engine will wear out with use. Over time, gaps will appear, causing noise during operation. If not addressed promptly, it may lead to chain skipping, which can damage the engine. Therefore, it is recommended to replace it. Tensioner failure: Tensioner failure causes the timing chain to shake and produce impact noise. Worn tensioner pulley bearings or an overly tight tensioner can also result in timing chain noise.
A couple of days ago, my cousin's Emgrand had the same issue, and I accompanied him to the repair shop to watch the mechanic disassemble it. The mechanic said that chain noise is mostly due to insufficient oil lubrication, and suggested checking if the oil dipstick is below the minimum line. Using oil that's too thin is also not advisable; the Emgrand requires 5W-30 oil. If the chain has worn to the point of producing metal shavings, then the entire set needs to be replaced, including the gears and tensioner, with material costs over a thousand and labor costs even higher. My brother-in-law's car was left unattended for too long, causing the chain to skip teeth and bend the valves, resulting in over eight thousand in engine repairs. If the noise sounds like a bicycle chain rattling, get it checked immediately!
As a powertrain engineer with ten years of experience at an OEM, such abnormal noises typically stem from four causes: abnormal oil pressure in the chain tensioner leading to preload failure—inspecting the tensioner for sticking requires removing the oil pan; aging and cracking of the timing chain guide plastic—our tests showed a 20% probability of fracture in samples after 100,000 kilometers; inevitable noise when wear on the drive and driven sprocket teeth creates a gap exceeding 0.3mm; and insufficient lubrication across the entire chain due to clogged oil pump strainers. It's advisable to measure the chain length—replacement is mandatory if it exceeds the standard by 3%.
I've handled over 70 Geely Emgrand timing system repairs. Listen up: if there's a rattling noise during cold starts that disappears when the engine warms up, it means the chain has stretched. If you hear a clattering sound during acceleration, that's the guide rails shattered with metal particles in the oil. The worst is a high-pitched squeal when accelerating - that usually means the tensioner oil port is completely blocked. Remember these three diagnostic steps: First, check if the oil pressure warning light on the dashboard illuminates. Second, remove a spark plug to inspect the piston crown for scoring marks. Finally, use a stethoscope to listen near the valve cover - if you hear a hissing sound, repair immediately. Once metal shavings appear, the engine is done for!
