What Causes Insufficient Power After an Oil Change?
3 Answers
Reasons for insufficient power after an oil change include high viscosity of the new oil, a faulty oil filter, or overfilling of oil. Specific reasons are as follows: High viscosity of the new oil: Because the old oil has degraded over time, its viscosity decreases, reducing the engine's movement resistance. The new oil has higher viscosity than the old oil, which may result in increased fuel consumption or a feeling of insufficient power. Faulty oil filter: If the engine lubrication system hasn't been cleaned for a long time, deposits accumulate. Changing the oil will flush out some impurities, suspending them in the oil. This can clog the oil filter, leading to insufficient power. Therefore, it's generally recommended to replace the oil filter along with the new oil. Overfilling of oil: It's important to pay attention to the amount of oil added. Both overfilling and underfilling can cause insufficient power. The issue may improve after the second oil change.
Last time after getting an oil change at a roadside shop, I clearly felt the throttle become heavier. An experienced driver friend helped me analyze several possible reasons: the workers might have overfilled the engine oil, with the dipstick reading almost above the maximum mark, increasing crankshaft stirring resistance; they might have used higher viscosity oil - I checked the manual and found the factory recommends 5W-30, but the shop used 10W-40; or there could be leakage from a loose drain plug or improperly installed oil filter. Later inspection revealed they had indeed overfilled by half a liter - after removing the excess, the power returned to normal. I recommend everyone check their dipstick after oil changes rather than relying entirely on the mechanics' work.
I've encountered this situation before. Last year after maintenance, my car always felt sluggish when accelerating. The mechanic told me several common reasons: overfilling engine oil increases engine load; using high-viscosity oil incorrectly affects lubrication flow; residual impurities in old oil filters can clog new oil passages; also some models require ECU reset because sensors might misjudge after oil change. He said using wrong oil grade is most common, especially switching to high-viscosity oil in winter, and recommended checking the manual for specifications. I finally discovered the oil filter wasn't installed properly causing pressure loss, and reinstalling it solved the problem.
