Here's a breakdown of the likely causes and what to do:
Possible Causes:
* Oil Pump Failure: This is a very common culprit. The oil pump is responsible for circulating oil. A failed pump won't pressurize the system, even with oil present.
* Oil Pump Pickup Tube: This tube draws oil from the bottom of the oil pan to the pump. If it's clogged, damaged, or detached, the pump won't get oil.
* Clogged Oil Filter: A severely clogged filter will restrict oil flow, preventing sufficient pressure. While less likely to cause *zero* pressure, it's worth checking.
* Worn or Damaged Engine Bearings: Severely worn bearings can allow oil to leak past them, reducing system pressure. This often results in knocking noises prior to complete failure.
* Broken or Damaged Oil Pressure Sensor: This sensor measures and sends the oil pressure signal to the gauge. A faulty sensor could be giving a false reading, although you should still hear a low oil pressure warning.
* Leaky Oil Cooler: This can lead to a pressure drop.
* Low Oil Level (despite thinking you have plenty): While you believe you have plenty, there might be less than you think due to a faulty dipstick reading or inaccurate gauge. Verify the level carefully.
What to Do:
1. Do NOT start the engine again. Running the engine without oil pressure will cause rapid and irreversible damage.
2. Check the oil level: Even though you think it's full, double-check using the dipstick. Ensure the oil is at the correct level.
3. Check the oil filter: It's easy to quickly check if the filter is severely clogged (though it rarely causes *no* pressure).
4. Inspect the oil pressure sensor: It's a relatively inexpensive part. You can test it with a mechanical oil pressure gauge.
5. Have it towed to a qualified mechanic: This is crucial. Diagnosing and repairing a lack of oil pressure requires expertise and specialized tools. Trying to fix it yourself could lead to further damage and costly repairs.
Important Considerations:
* Cost: Repairing the problem could range from a relatively inexpensive oil pump replacement to a complete engine rebuild, depending on the cause.
* Age and condition of the vehicle: A 2004 vehicle might have other underlying issues contributing to the problem.
Ignoring this problem will almost certainly lead to a very expensive engine rebuild or replacement. Get it towed to a mechanic as soon as possible.
