Why is my engine making a knocking sound when cold?
I have a SEAT Leon 2015. When cold there is a knocking noise coming from the engine. It sounds like it is in the area in front of the steering wheel. It's always when started and seems to go away after the engine warms up or when it reaches third gear. It is a loud knocking sound. Any thoughts would be greatly appreciated.
Asked on 15 February 2026 by Sandra
Answered by
Alan Ross
If you have a TSI engine fitted then the most likely reasons for this are:
1 Timing chain tensioner/chain (TSI Engines): A common issue where the tensioner fails to hold pressure, allowing the chain to slap on cold start. This often presents as a rattle that vanishes within 30-60 seconds as oil pressure builds.
2 VVT magnets/solenoids: If the noise occurs while revs drop after a fresh cold start, it could be the Variable Valve Timing solenoids, often located near the timing chain.
3 Hydraulic lifters (Valvetrain): If the noise is a fast tapping or knocking from the top of the engine, it is likely a lifter that has gone "flat" and takes time to fill with oil.
4 Oil viscosity/pressure: Cold, thick oil or low oil levels can cause temporary oil starvation during startup.
We would suggest that you look for a local garage and get them to carry out further checks
1 Timing chain tensioner/chain (TSI Engines): A common issue where the tensioner fails to hold pressure, allowing the chain to slap on cold start. This often presents as a rattle that vanishes within 30-60 seconds as oil pressure builds.
2 VVT magnets/solenoids: If the noise occurs while revs drop after a fresh cold start, it could be the Variable Valve Timing solenoids, often located near the timing chain.
3 Hydraulic lifters (Valvetrain): If the noise is a fast tapping or knocking from the top of the engine, it is likely a lifter that has gone "flat" and takes time to fill with oil.
4 Oil viscosity/pressure: Cold, thick oil or low oil levels can cause temporary oil starvation during startup.
We would suggest that you look for a local garage and get them to carry out further checks
Similar questions
I recently had my fuel injectors renewed at a garage. The car ran fine for two months then just cut out on a short motorway journey. I took it back to the garage to be told that an intake valve was broken...
My Volkswagen 1.6 TDI engine was running perfectly but one morning when I started the engine, it chugged and now holds the revs. It revs up and down with lots of black smoke. What's wrong?
I have just found oil in my radiator and expansion tank. Any thoughts/suggestions as to what this could be?
Elsewhere on 
