If you have replaced the engine oil filter recently and observe oil stain on the car undercarriage and the floor, it might be cause by oil filter leakage. Usually it is cause by the below reasons:
1. Perhaps the rubber seal is not replace when replacing the new oil filter, or when the old oil filter is taken out, the rubber seal still attach on the oil filter seat. If it is not check properly and a new oil filter is installed to it directly, it might cause oil leakage.
2. Improper handling during servicing such as installing the oil filter too loose or too tight, or installing an incompatible oil filter type, will cause the engine oil leak out from the oil filter. Suggest to repair at a more reputable workshop as soon as possible.
3. Use of bad quality oil filter purchased online. Although the price is competitive but the quality is inconsistent which may easily cause oil leakage. Suggest to buy genuine oil filter in order to avoid bigger damage done to the car.
4. Severe contamination occur in the lubricating system causing main oil channel clogged and a series of pressure effect. The pressure may impact the oil filter rubber seal causing leakage to happen.
Suggest to diagnose at workshop, usually the keypoints of diagnose are:
1. Check if the oil sump drainage screw is loosen.
2. Check if the engine oil filter is dirty, replace if necessary.
3. Check if the engine oil filter rubber seal is deteriorated, replace if necessary.
4. Check if the channel of lubricating system is clogged, reolve it if it is faulty.