LOW RISK
Common symptoms
- See page for quick checks
Cost expectations
Typical costs vary by car and region. Use this as a ballpark.
- DIY / parts: £20–£80
- Garage / labour: £80–£250
Most likely causes (ranked)
Start at the top. Rule out the common, cheap causes before expensive ones.
- Cabin filter dirty
- Evaporator bacteria
- Blocked drain
- Old AC treatment
- Water ingress
Quick checks (fast, low-cost)
Fast checks you can do with basic tools before buying parts.
- Replace cabin filter.
- Run AC disinfectant/foam treatment.
- Check AC drain is dripping under car.
- Dry system by running heat/AC cycle.
- If damp carpets, fix water ingress.
Recommended tools
These tools make diagnosis faster and stop you buying random parts.
Related fixes
If your symptoms don’t match perfectly, check these next.
What to do next
- If smell returns quickly, clean evaporator and clear drain.