Why does the engine idle shake severely after an oil change?
3 Answers
The reasons for severe engine idle shaking after an oil change are: 1. Overfilling of engine oil; 2. Incorrect oil specification; 3. Faulty spark plugs or ignition coils; 4. Oil dripping onto the oxygen sensor. Engine oil, also known as motor lubricant, is composed of base oil and additives. The steps for changing engine oil are: 1. Lift the vehicle, remove the undercover, and place a container of about 10 liters under the oil drain plug; 2. Unscrew the oil drain plug, use an air gun to blow into the oil filler opening for two minutes, tighten the drain plug after draining, and wipe it with a tissue to check for leaks; 3. Reinstall the undercover, lower the vehicle, and use a funnel to add oil into the filler opening.
I've driven quite a few cars, and this is a common issue. It could be due to overfilling or underfilling of engine oil, as improper oil level directly affects engine lubrication. When there's too much oil, it interferes with the crankcase ventilation system, causing unstable idling; insufficient oil means the engine isn't properly lubricated, leading to similar shaking. Additionally, if the new oil is of poor quality or the wrong type (e.g., switching from 5W-30 to a higher viscosity), it can disrupt oil circulation. Another possibility is related to the air filter—accidentally bending the air duct during an oil change or causing a vacuum leak can lead to inaccurate readings from the air flow sensor, messing up the ignition timing. Or, it might be time to replace the spark plugs, and the oil change just brought the old issue to light. I recommend checking the dipstick immediately to see if the oil level is within the normal range—adjust if it's too high or too low. It's also good to recall the oil change process: was the manufacturer-recommended specification used? If necessary, visit a professional shop to inspect the electrical and intake systems. Don’t underestimate this shaking—it could accelerate engine wear and increase fuel consumption. Fixing it sooner is more cost-effective.
As someone who frequently tinkers with cars, I believe that idle vibration after an oil change likely stems from minor details. For instance, if the new oil has a higher viscosity than the previous one, the engine encounters greater resistance during cold starts, leading to unstable idling. If the technician forgets to reset the oil life counter, the ECU may not adapt to the new oil parameters properly. Another possibility is that the oil pan drain plug or filter wasn't tightened securely during the oil change, causing minor leaks or air ingress, which affects oil pressure. Loose vacuum hoses are also quite common, as oil change procedures often involve handling these lines. I can share an experience—last time my car shook, it was due to a loose vacuum hose, and the issue was resolved immediately after tightening it. I recommend doing a quick inspection yourself: first, check the oil level and color (ensure it's not too dark or contaminated), verify that the filter is correctly installed, and then listen for any unusual engine noises. If necessary, use an OBD scanner to check for trouble codes—don't let minor issues escalate into bigger problems that compromise driving smoothness or harm the vehicle. Preventive maintenance is crucial, so next time you change the oil, supervise the entire process.
