Q: Oil pressure light came on. Changed the sensor. Ran fine. Light went off. But when I got my oil changed they said there was water

Moisture in the air (water vapor) can condense in the engine and contaminate the oil. The amounts are typically not significant and the water eventually vaporizes in hot operation and leaves the engine. The other source of water is from the engine coolant and this would not be water alone but rather a water anti-freeze mix. Antifreeze in engine oil will damage the engine. To determine if the contamination in the oil is water or anti-freeze, the oil can be tested. If it turns out to be water, you need do nothing. If it is antifreeze though the leak point should be identified and repaired. If you desire that this concern be investigated and resolved please schedule service at YourMechanic’s leak diagnostic inspection service page and the responding certified mechanic will get this diagnosed and resolved, right at your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.