A small amount of oil under your car after an oil change is often due to residual spills from the service or an issue with a newly replaced component. While concerning, it's usually easily identifiable and correctable.
Common Reasons for Post-Oil Change Oil Drips
Several factors can lead to those unwelcome oil spots. Here's a breakdown of the most common culprits:
1. Residual Spills from Oil Filter Replacement
During an oil change, the oil filter's placement on some engines means that oil will inevitably spill out as the filter is being removed and replaced. This spilled oil can collect on engine components, the subframe, or protective underbody shields. Even after the change is complete, this residual oil can slowly drip down, creating small puddles.
- What to look for: Small, dispersed drips that stop after a day or two. The oil might appear on various parts of the engine bay.
- Solution: Often, this oil will burn off or stop dripping on its own. You can also gently clean the area around the oil filter housing with an engine degreaser if easily accessible.
2. Loose or Improperly Sealed Drain Plug
The drain plug is crucial for sealing the oil pan after the old oil has been removed. If the drain plug wasn't tightened sufficiently, or if it didn't seal the oil pan completely, a small amount of oil can seep out. This can happen if the plug is cross-threaded, not tightened to the correct torque, or if the drain plug washer (gasket) is old, damaged, or missing.
- What to look for: A drip directly beneath the oil pan drain plug. The oil might feel slightly wet around the plug itself.
- Solution: Gently tighten the drain plug (being careful not to overtighten, which can strip the threads). If the washer is the issue, it needs to be replaced. Most reputable oil change services replace this washer as standard practice.
3. Faulty or Incorrectly Installed Oil Filter
An improperly installed oil filter can also cause leaks. This includes:
-
Cross-threading: If the filter isn't screwed on straight, it can damage the threads and prevent a proper seal.
-
Missing or double gasket: The new filter comes with a rubber gasket. If the old gasket sticks to the engine and a new one is installed over it, or if the new gasket isn't seated correctly, it will leak.
-
Insufficient tightening: The filter needs to be hand-tightened firmly, usually with an additional quarter to half-turn with a wrench, according to manufacturer specifications.
-
Damaged filter: Although rare, a new oil filter could be defective.
-
What to look for: Oil leaking from the area where the oil filter connects to the engine block.
-
Solution: Carefully inspect the oil filter. If it appears loose, try to tighten it by hand. If it's cross-threaded or has a double gasket, it will need to be removed and reinstalled correctly with a new gasket.
4. Damaged Drain Plug Washer/Gasket
Each time the drain plug is removed, its washer (a small ring that helps create a seal) should ideally be replaced. These washers are typically made of metal or composite material and compress to form a tight seal. If an old, worn, or damaged washer is reused, it won't seal properly, leading to a slow leak.
- What to look for: Similar to a loose drain plug, oil will drip from the drain plug area.
- Solution: The washer needs to be replaced. This usually requires draining the oil again, replacing the washer, and refilling the oil.
What To Do If You Find Oil Under Your Car
It's important to address oil drips promptly to prevent potential engine damage or environmental concerns.
- Identify the Source:
- Place a clean piece of cardboard under your car to help pinpoint where the drips are coming from.
- Visually inspect the area around the oil filter and the drain plug with a flashlight.
- Check Your Oil Level: Use your car's dipstick to check the engine oil level. If it's significantly low, this indicates a more serious leak that requires immediate attention. Learn how to check your oil level accurately here (example link).
- Contact the Service Provider: If you just had an oil change, the first step is to contact the garage or technician who performed the service. They should be able to inspect the car and correct the issue at no additional cost.
- Monitor the Leak: If the leak is very minor and you suspect it's residual, keep an eye on it for a day or two. If it persists or worsens, seek professional help.
Preventative Measures
To minimize the chances of post-oil change leaks:
- Choose Reputable Service Centers: Opt for mechanics or service centers with good reviews and experienced technicians.
- Ask About Best Practices: Inquire if they routinely replace the drain plug washer and properly torque the drain plug and oil filter.
- Briefly Inspect After Service: Before leaving the shop, a quick glance under the car for any obvious drips can sometimes catch issues early.
| Potential Issue | Symptoms | Recommended Action |
|---|---|---|
| Residual Spill | Small, dispersed drips, often temporary | Monitor, clean if accessible, usually resolves itself |
| Loose Drain Plug | Drip directly under drain plug, wet plug area | Gently tighten, replace washer if necessary |
| Improperly Installed Oil Filter | Leak from filter housing, oil on filter | Inspect, tighten, or reinstall with new gasket |
| Damaged Drain Plug Washer | Drip directly under drain plug | Replace washer (requires draining oil) |
Understanding these common causes can help you quickly address the issue and ensure your vehicle remains in top condition.
