Is it necessary to replace hydraulic tappets if they make a ticking sound?

[VanKatherine]

Whether it is necessary to replace hydraulic tappets that make a ticking sound depends on the situation: 1. For trucks, the clearance of hydraulic tappets can be adjusted, so simply take it to a repair shop for adjustment; 2. For passenger cars, their hydraulic tappets are hydraulic and cannot be adjusted—they can only be replaced. Sometimes, even the tappets cannot be replaced, but if the tappet base is worn, the cylinder head may need to be replaced. Hydraulic control uses pressurized liquid as the medium for transmitting control signals. A control system constructed using hydraulic technology is called a hydraulic control system, which typically includes hydraulic open-loop control and hydraulic closed-loop control, together forming a hydraulic servo system. A complete hydraulic system consists of power units, actuating devices, control and regulating devices, auxiliary devices, and liquid medium.

[SanElisa]

Last month, my car also had this ticking sound, so I specifically asked an experienced mechanic at the repair shop. He said it's normal for it to tick for a few seconds during a cold start, but if it keeps ticking like a sewing machine even when the engine is warm, it's most likely an issue with the hydraulic lifter. My car previously had a clogged oil pump screen, which caused insufficient oil supply, but after changing the oil and filter, it became quiet. He reminded me that if it's accompanied by sluggish acceleration or a sudden spike in fuel consumption, it must be checked immediately, or it could damage the camshaft by creating pits. If unsure, you can use a long screwdriver to press against the engine and listen—the lifter with the unusually crisp sound is the problematic one.

[Pluto]

My old Mercedes had the same issue at 200,000 km, and the advice from my trusted mechanic was very practical. If the ticking sound gets louder when you step on the gas, it's almost certain that the hydraulic lifter is worn out, causing excessive valve clearance. He taught me a simple trick: after turning off the engine, press each valve rocker arm one by one—the one with obvious looseness and gap is definitely faulty. However, he mentioned that replacing just one lifter is prone to failure again, so he recommended replacing the entire set for better durability. The key is to determine whether it's a problem with the lifter itself or insufficient oil pressure. In my case, the inspection revealed that the oil pan gasket had aged, causing a slight oil leak.

[HannahFitz]

As someone who has experienced this, my advice is to observe the pattern of the noise. If it occurs when the engine is cold but disappears when warm, you can monitor it first. However, if the noise persists when the engine is hot, you should be cautious. Last time, I ignored this issue for three months and ended up spending nearly six thousand yuan on camshaft repairs. The technician mentioned that if the ticking frequency is synchronized with the engine RPM, you need to pay special attention. A failing hydraulic lifter can cause inaccurate valve opening and closing, potentially leading to piston-to-valve contact. During diagnostics, they often use a stethoscope to locate the problematic lifter. After identifying it, they check if the oil pressure meets the standard before deciding whether to replace it.