Rattle for two seconds on a cold start, then a warning light
- Make and model
- Volkswagen Polo V
- Year
- 2011
- Engine
- 1.2 TSI (CBZB)
- Fuel
- Petrol
- Mileage
- 88,000 km
Customer complaint
A loud rattle for two to three seconds on cold starts, worse after the car has stood for a few days. Now the engine warning light is on and the idle is slightly rough.
Fault codes
| Code | Description | Status |
|---|---|---|
| P0016 | Crankshaft Position – Camshaft Position Correlation (Bank 1 Sensor A) | Confirmed |
Measurements and live data
| Parameter / measurement | Measured | Expected |
|---|---|---|
| Camshaft position deviation (live data) | 8° crank | a few degrees at most |
Tests performed
- Cold start after standing overnight, listening at the timing coverChain rattle for about 2 s until oil pressure builds
- Timing cover removedChain stretched, tensioner at full extension, guide worn
- Compression test after the repairAll cylinders even, no valve damage
Solution
Root cause
Timing chain stretched and its guide worn, so the tensioner could no longer take up the slack on cold starts.
Repair
Replaced the chain, tensioner (latest version), guides and sprockets, set the timing with the locking tools and cleared the code. Cold starts quiet, camshaft deviation back near zero.
Parts
Timing chain kit, cover gasket, oil and filter
Labour time
4.5 h
Lesson learned
Act on the first cold-start rattle: a few more weeks and the chain can jump and bend the valves.
Training case: the usual fix for this fault, not a confirmed repair on a specific car.
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