Compact petrol saloon · 2016 · 98 000 km · Petrol
Metallic knock for about 30 seconds on cold start. The noise then disappears. No warning light. Oil change done 14 months ago.
REAL-WORLD CASEWHAT THE DRIVER DESCRIBED
A knock on cold start
Illustrative example of a full report. Generic vehicle and situation, not linked to a real customer.
THE REPORT01 02 03
Your initial insight.
A brief metallic noise, only when cold, that disappears as the engine warms up points first to lubrication and timing. No warning light is reassuring, but this symptom should not be ignored.
Possible causes and checks
Old oil or low level
After 14 months, oil may have lost its properties. When cold, it takes longer to reach every part, which can cause a brief knock.
- Check the dipstick level with the engine cold and on level ground
- Check the date and viscosity of the last oil change
Timing chain tensioner
On a chain engine, the tensioner works with oil pressure. Until pressure builds, the chain can slap and make noise.
- Ask for the timing side to be listened to on cold start
- Ask whether timing values can be read
Hydraulic lifters
These parts fill with oil. A lifter that drains while parked can tap for a few seconds at start-up.
- Note whether the noise sounds like a fast ticking at the top of the engine
Indicative budget
The budget depends heavily on the cause. An oil change is quick; timing work requires much more labour. These amounts are benchmarks to confirm with a quote.
90 – 900 €
Questions to ask the garage
- Did you listen to the noise with a cold engine before proposing a repair?
- Is an oil change enough to rule out the timing?
- Which exact parts are replaced, and why?
- Analysis based solely on the description provided, without listening to or inspecting the vehicle.
- Indicative preliminary diagnosis. Does not replace a vehicle inspection by a professional.
Is your situation different?
Describe your vehicle and what you observed: the analysis is based on your case.
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