The K4M engine was fitted to the Renault Logan, Sandero, Duster, Megane and related models, and one complaint has followed it for most of its life: a sharp ticking from under the valve cover on a cold start. The phrase “the hydraulic lifters are knocking” is usually right about the address but not always right about the conclusion — because the lifters themselves are more often the victim than the culprit. Here is the mechanism and the order of work.
How it works and why it ticks
A hydraulic lifter is a small plunger cup between the camshaft lobe and the valve. Engine oil is fed into it under pressure, the plunger extends and takes up the thermal clearance so that the valve train always works without free play. While there is oil inside, the clearance is zero and there is no sound. As soon as the oil escapes or its pressure falls, a gap opens between the lobe and the follower — and every revolution of the camshaft becomes an impact, heard as rapid, sharp ticking from the top of the engine.
Hence a simple rule: a lifter ticks either because it is not receiving oil of the right quality and pressure, or because it can no longer hold the oil inside — through wear in the plunger or coked-up passages. The first case is cured by servicing, the second by replacing parts.
Normal, or no longer normal
| The pattern of the sound | What it usually means |
|---|---|
| Ticking for 2–5 seconds after starting, then silence | Standard behaviour; the oil has not filled the lifters yet |
| Ticking for up to a minute in the cold, then gone | Borderline: oil viscosity, early-stage wear |
| The noise stays after warm-up | Worn lifters, blocked passages, oil pressure |
| One or two distinct “voices” ticking | Specific lifters or their oil passages |
| A dull knock that grows under load | No longer the valves — look lower down the engine |
The decisive marker is warm-up. Ticking that honestly disappears once the engine is warm rarely needs immediate intervention. A knock that stays on a hot engine is worth showing to a mechanic. The sound portraits of this group and its neighbours are on the symptom page engine knock when cold.
What it is not
The first thing to rule out is the timing drive. The K4M uses a belt, so the characteristic chain rattle at startup should not be present here. Second, the cam phaser: on engines that have one, a short rumble at startup comes from it, and the cure is different from valve ticking. Third, the accessory drive: idlers, tensioner, alternator. Those are checked by seeing how the sound changes with the accessory belt removed.
The practical order of diagnosis looks like this: check the level and condition of the oil, recall when it was changed and which viscosity went in, listen to the engine with a stethoscope at points across the valve cover, and measure oil pressure if needed. Only after that does it make sense to talk about removing camshafts.
How the repair is decided
The order of spending follows the order of likelihood. Oil and filter first, then two or three cold starts of observation, and only then the cylinder head. The question is closed at the first step surprisingly often — particularly if the oil ran longer than it should have, or was chosen by guesswork rather than by specification.
If the lifters do turn out to be worn, two things are worth agreeing before the work starts. The whole set is replaced rather than the noisy one: they have the same age and the same mileage, and doing one means paying for the same disassembly twice. And the camshaft lobes are inspected while the engine is open — a lifter that has been ticking for months leaves marks on the lobe, and finding that out afterwards is the expensive way.
To judge whether your ticking falls within normal, record the sound in the Pro-Stuk app right after a cold start and again on a warm engine. The app compares the recordings with your answers about mileage and the last oil change and shows the likely causes with percentages — along with a hint on whether to go to a workshop now or change the oil and listen again.
