Getting oil out of spark plug wells is an important part of engine maintenance. Over time, oil can seep down into the spark plug wells and cause issues with starting, idling, and engine performance. Fortunately, there are a few methods you can use at home to remove oil from the spark plug wells to keep your engine running properly.
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What Causes Oil to Get in Spark Plug Wells?
There are a few common causes of oil getting down into the spark plug wells:
- Worn valve guide seals – The valve guide seals keep oil from getting into the combustion chamber, and when they wear out, oil can seep past into the cylinder and make its way down into the spark plug well.
- Worn piston rings – Worn piston rings allow combustion gases to get into the crankcase. This pushes oil mist up into the cylinder, which then drips down into the spark plug wells.
- Excess oil consumption – If your engine is burning or consuming more oil than normal, that oil has to go somewhere, and some of it can end up in the spark plug wells.
- Overfilling oil – Putting too much oil into the crankcase can cause oil to get pushed up into the combustion chamber and then drip down into the spark plug wells.
So if you have an older engine with higher mileage, worn seals and piston rings are likely allowing oil to seep into places it shouldn’t be. But even on newer engines, oil consumption issues or overfilling oil can lead to spark plug well contamination.
Should You Try to Remove Oil from Spark Plug Wells?
If you notice symptoms of oil getting into the spark plug wells like hard starting, rough idling, misfires, or fouled spark plugs, then you definitely need to take action to remove the oil from the wells. Here are some key reasons you need to get the oil out:
- Oil fouls the spark plugs – Oil coats the spark plugs’ firing ends, causing misfires. The engine won’t run properly if the plugs can’t fire correctly.
- Oil causes hard starting – The oil in the wells causes the plugs to misfire when trying to start the engine. This leads to a lot of cranking before it starts.
- Idling issues – Oil contaminated spark plugs and wells can cause unstable idling, stalling, or even engine stumble.
- Performance loss – The presence of oil reduces combustion efficiency and horsepower output from your engine.
So if you notice any of those issues, it means there is likely oil in the spark plug wells that needs to be removed to restore proper engine performance. Driving with oil fouled plugs can also cause additional engine damage over time.
How to Remove Oil from Spark Plug Wells
Here are some of the most effective DIY methods for getting oil out of spark plug wells at home:
1. Use Compressed Air
One of the easiest methods is to use compressed air to simply blow out the oil from the spark plug wells. Here’s how to do it safely:
- Remove all the spark plugs from the engine.
- Set your air compressor to 30-40 psi maximum.
- Use a blow gun attachment on your air hose.
- Insert the blow gun into each spark plug well, angled downward.
- Blow 2-3 strong bursts of air into each well.
- Wipe away any oil residue with a clean rag.
- Reinstall the spark plugs and reconnect ignition coils as needed.
The compressed air will force most of the oil out of the wells. Be sure to keep the psi low to avoid any engine damage. Wear eye protection as well during the process.
2. Use a Vacuum
You can also use an ordinary wet/dry shop vacuum to suck the oil out of the wells. Here’s how to do it safely:
- Remove the spark plugs to open access to the wells.
- Insert the narrow suction tube down into each spark plug well, angled slightly.
- Turn the vacuum on and move the tube around to suck up oil residues.
- Optional – Insert a clean rag into the tube to wipe away any remaining oil.
- Reinstall spark plugs when finished.
The suction of the shop vac will pull a good amount of the oil out. Use a narrow tube to reach down into the wells. Make sure to dispose of any oily rags properly.
3. Use a Spray Solvent/Cleaner
Another option is to use a cleaning solvent specifically made for spark plug wells and combustion chambers. Here are the steps for using solvent spray cleaners:
- Remove spark plugs to access the wells.
- Shake the cleaner spray can well.
- Insert the thin nozzle tube into the spark plug wells.
- Spray the cleaning solvent into the wells for 2-3 seconds each.
- Let the solvent soak for 5 minutes.
- Use compressed air to blow out the wells.
- Reinstall spark plugs.
The solvent will break down the oil residues and make it easier to remove. Be sure to let it soak long enough before blowing it out. Follow all safety directions for the cleaner.
4. Use an Oil Well Cleaning Brush
For wells with heavy oil contamination, a purpose-made brush can scrub the oil away. Here’s how to use a well cleaning brush:
- Remove spark plugs to access the wells.
- Insert the spiral steel brush into a well and rotate it in and out.
- Scrub to scrape away built-up carbon and oil deposits.
- Use a vacuum or compressed air to remove the loosened contaminants.
- Repeat the brushing process for each well.
- Reinstall spark plugs when finished.
The brush scrubs away even baked-on carbon and oil. Be careful not to scratch or score the wells. This works best along with spray solvents.
Tips for Preventing Oil in Spark Plug Wells
To help prevent oil from getting back into the spark plug wells after cleaning them, consider these maintenance tips:
- Use high quality oil – Higher quality motor oils are less likely to be consumed and make their way into combustion chambers.
- Change oil regularly – Follow the recommended oil change intervals to keep oil fresh.
- Check seals and gaskets – Replace leaky valve seals and piston rings that can allow oil seepage.
- Don’t overfill oil – Adding too much oil promotes oil blow-by into the cylinders.
- Address oil consumption – Get oil consumption issues diagnosed and repaired.
- Clean air filter – Clogged filters allow more contaminants into cylinders to foul plugs.
- Consider catch cans – They collect blow-by oil to keep it from reaching cylinders.
Staying on top of overall engine maintenance will minimize oil contamination in spark plug wells and other areas. But even well-maintained engines can suffer from some oil blow-by over time.
When to Call a Mechanic for Help
While the DIY methods can handle light to moderate oil contamination, it’s best to have a professional mechanic tackle heavier oil fouling issues. Here are some signs it may be time to take your car into the shop:
- Oil fouling returns quickly after cleaning
- Spark plugs remain fouled after cleaning wells
- Heavy oil sludge present in the wells
- Misfires or poor running continue after cleaning
- Excessive oil consumption or leakage
- Worn piston rings or valve guide seals
If you already have higher mileage or suspect bigger issues are causing the oil in the wells, don’t hesitate to have a mechanic inspect it. They can determine if engine repairs are needed and properly clean hard-to-reach areas.
Conclusion
Oil getting down into the spark plug wells is a common issue that can’t be ignored. Allowing the oil to remain in the wells will lead to spark plug fouling, difficult starting, rough idling, and loss of engine power. Thankfully, there are several effective DIY methods for removing oil from the wells at home.
Using compressed air or a vacuum to simply blow or suck the oil out usually works well for light contamination. Stubborn oil residue may need a solvent cleaner and some agitation with a special brush tool. Preventing future oil intrusion comes down to adhering to strict engine maintenance. But even well-serviced engines may need an occasional spark plug well cleaning over time.
With some simple tools and supplies, you can successfully remove problematic oil from your car’s spark plug wells. Just be sure to take added precautions if the fouling seems excessive, as that may indicate larger engine issues. Paying attention to oil fouled spark plugs and addressing it promptly will keep your car running smoothly.