Will it leak oil if the drain plug washer is forgotten?
3 Answers
Oil may seep out when the seal is not tight, but it won't leak if the seal is tight. Here are the relevant details: 1. The washer added before tightening the drain plug serves as a seal. Forgetting to add the washer can easily lead to oil leakage, which may affect the engine's operation. The contact surfaces between the drain plug and the oil pan are mechanical and cannot be perfectly flat. Without a washer, they cannot achieve a complete seal. The washer fills the gaps between them, ensuring a sealed state. 2. The washers commonly used are made of aluminum. When tightening the screw, the soft aluminum material easily deforms to fill the gaps. However, the tightening force must be properly controlled. Too little force may result in insufficient deformation of the washer, failing to fill the gaps and causing leakage.
Forgetting to replace the washer during an oil change can indeed cause leaks, as that small metal piece (usually made of copper or aluminum) serves to seal the tiny gap between the drain plug and oil pan. Without it, even a tightly screwed plug may leave micro-gaps, allowing engine oil to gradually seep out due to internal oil pressure. Initially, you might just notice a few oil drips staining your parking spot, but prolonged leakage can become continuous—not only wasting your car's precious oil but potentially causing low oil levels that damage internal engine components. I recommend checking immediately: wipe the drain plug area clean with a cloth, drive a short distance, then inspect for fresh oil stains. If leakage signs appear, promptly install a new washer and top up the oil level. Always remember this small but critical part during routine maintenance—it prevents major headaches.
Having driven for decades, I've seen too many people make this mistake – forgetting to install the washer on the drain plug, which will absolutely cause oil leaks! This little part isn't as noticeable as major components, but without it, the seal fails completely. I've experienced this myself – a few days after an oil change, I smelled oil and found the area around the drain plug wet upon inspection, with a significant drop in oil level. The reason is simple: the small washer compresses and deforms to seal potential gaps; without it, the smooth bolt can't hold against oil pressure. The fix is easy – buy a matching washer from an auto parts store, clean the area thoroughly before installation. Afterwards, always check the dipstick to ensure proper oil level. This small oversight can cause big trouble, so make checking the washer a mandatory part of every maintenance routine.
