Check Engine Lights After Changing Oil

You’ve just replaced the oil in your car. However, as soon as you started the engine, the ominous Check Engine Light (CEL) came on in the dashboard. What could be the reason for this unexpected occurrence? How can you effectively solve this issue?

In this comprehensive guide, we will explore various possible reasons for the CEL coming on after an oil change (OC). We’ll discuss methods to address these problems, extinguish the light, and provide additional recommendations to help you tackle this situation.

Understanding the Check Engine Light After an Oil Change

As mentioned earlier, there could be several factors that trigger the CEL to come on after an OC.

Reasons Check Engine Light Appear After an Oil Change

Below, we detail the most common reasons for the CEL to illuminate after an OC:

• Improperly Installed Dipstick: During an OC, the dipstick is often removed, cleaned, and reinserted to check the oil level. An improperly installed dipstick might allow air to enter the engine, potentially causing damage to internal components such as valves, pistons, and cylinder walls. This could lead to the appearance of the CEL;
• Fuel Cap Mismatch: After refueling post-OC, you might accidentally misplace the fuel cap, leaving it loose or not securing it properly. While a minor issue, it can trigger the CEL;
• Low Oil Pressure: Changing out old oil and introducing new oil during an OC could mean that the oil pressure gauge requires time to restore pressure. If the gauge doesn’t calibrate quickly enough, the computer might interpret it as low oil pressure, causing the CEL to activate;
• Incorrect Oil Type: Using an unsuitable oil type can lead to problems triggering the CEL. Different motor oils have varying viscosity, mass, and classifications. Using oil that doesn’t match the vehicle’s technical specifications could compromise lubrication and heat exchange, resulting in the CEL illumination;
• Oil Overfill: Pouring too much oil into the engine can slow down its operation, cause improper functioning, emit smoke from the exhaust pipe, or result in oil leakage. These issues can lead to the CEL turning on.

Resolving the Check Engine Light After an OC

Addressing the CEL issue after an OC involves a careful engine inspection and taking steps to rectify it:

Troubleshooting

• Dipstick Adjustment: Ensure the dipstick is correctly inserted. Inspect the dipstick and its tube for any clogs, then reinsert the dipstick properly;
• Correcting Oil Type: If the wrong oil brand was used, drain it immediately and replace it with the appropriate type of oil. It’s also recommended to change the oil filter;
• Checking the Fuel Cap: Ensure the fuel cap is securely fastened and closed properly;
• Adjusting Oil Level: In the case of oil overfill, use a suction pump to remove excess oil through the dipstick tube or cap orifice.

Allow the car to run for a few minutes to ensure oil circulation and resolve any potential low oil pressure issues.

Resetting the CEL After an OC

If, despite the actions described above, the indicator doesn’t turn off, use either the manual or tool-based reset methods:

• Disconnecting the Battery Terminal: Disconnect the positive terminal of the battery for 15-20 minutes, then reconnect it. This action clears the fault codes responsible for illuminating the CEL indicator, leading to its deactivation;
• Using an OBD II Scanner: To access fault codes and the “Clear” function, use an OBD II scanning tool.

Clearing the codes will reset the CEL indicator.

Driving with the CEL After an Oil Change

While not recommended, driving with the CEL illuminated after an OC might be safe as long as the vehicle behaves normally. However, if the light remains on, it’s advisable to promptly consult a mechanic for a comprehensive diagnosis.

Shaking and CEL After an OC

Engine vibration accompanied by the CEL turning on can result from causes such as using the wrong oil type, oil overfill, low oil level, clogged air filter, or disconnected sensor. These factors are common reasons for the CEL to illuminate after an OC.

To resolve this issue, monitor the oil level, check the air filter’s positioning, use the correct oil type, and inspect disconnected sensors.

Understanding Oil Viscosity and Check Engine Light

Yes, oil viscosity can indeed contribute to the activation of the Check Engine light. Oil viscosity refers to its resistance to flow and shear.

Using oil with an improper viscosity level—either too thin or too thick—can lead to insufficient lubrication or flow restriction, potentially triggering the CEL. To address this problem, use motor oil with the appropriate viscosity.

Driving with the Check Engine Light After an Oil Change

It’s not recommended to drive with the CEL on, especially if it’s flashing. A flashing CEL indicates a serious problem that requires immediate attention. If the light comes on, assess the car’s behavior—check for unusual noises, vibrations, or jerking.

While driving might still be possible, it’s advisable to visit a mechanic for diagnosis and resolution.

In Conclusion

The illumination of the CEL after an oil change can be concerning, especially if accompanied by engine vibration. The main culprits behind this issue include improper oil use, incorrectly installed components, low oil pressure, and oil overfill. Fortunately, you can often address these factors on your own using the methods outlined in this guide.

In cases where attempts to fix the issue don’t extinguish the light, seeking assistance from a specialist is recommended. Remember that the engine malfunction indicator is a valuable gauge of your car’s condition, and taking timely action to address it ensures the smooth and safe operation of your vehicle.

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