Should the Crankshaft Oil Seal Be Replaced if It's Leaking?
4 Answers
Crankshaft oil seal leakage should be replaced. If you notice severe engine oil leakage from the rear crankshaft oil seal while driving, the emergency measure is to add some engine oil to the crankcase and then drive the car to the nearest repair station as soon as possible for inspection. A better solution is to call a tow truck to take the car to an authorized 4S shop for repair. Reasons for rear crankshaft oil seal leakage: 1. Non-petroleum-based lubricants were not used during the installation of the crankshaft oil seal, or low-quality oil seals were used, causing the oil seal to loosen or even fall off after some time of engine use, leading to oil leakage from the rear crankshaft oil seal. In severe cases, oil may drip; 2. The parallelism of the rear oil seal mounting surface relative to the rear oil seal seat did not meet technical requirements, resulting in uneven force distribution on the oil seal lip. Over time, this can cause the oil seal to deform, twist, or age, leading to oil seal damage and engine oil leakage; 3. Prolonged use, high temperatures, or uneven force distribution can cause the rear crankshaft oil seal to age and leak oil. Severe leakage can result in insufficient engine sealing, failing to achieve the necessary lubrication effect.
I've been driving for many years and encountered crankshaft oil seal leakage several times. The first time it happened, I thought it was a minor issue and didn't replace it, but the leakage got worse and worse, causing continuous oil loss and nearly ruining the engine. Replacing the oil seal is quite necessary because leakage not only wastes oil but also destabilizes the internal pressure of the engine, affecting performance. If left unaddressed for a long time, it can contaminate surrounding components like belts or sensors, triggering a chain reaction. The repair isn’t difficult—just take it to a repair shop, and it can be replaced in an hour or two at a low cost. Don’t delay; inspect and replace it as soon as you notice any leakage. Regular engine maintenance can prevent this issue. Oil leakage is mostly caused by aging or installation errors and is more likely to occur in high-temperature environments. Proper maintenance can save you a lot of money.
As someone who repairs cars daily, it's best to replace a leaking crankshaft oil seal promptly. Leakage indicates the seal has lost its effectiveness, allowing engine oil to continuously escape. This can cause pressure imbalance during engine operation and potentially wear out internal bearings. I've seen many vehicles suffer from oil depletion and engine overheating (leading to cylinder seizure) due to delayed replacement. Though the cost is relatively small—typically ranging from 200 to 500 RMB for seal replacement—the process requires partial engine disassembly, so professional workshop handling is recommended. Take the opportunity to inspect the oil passages and airtightness, which can collectively extend engine lifespan. Oil leaks commonly occur in older or high-mileage vehicles, primarily due to heat and vibration. Developing a habit of checking engine oil levels enables early detection.
As an average car owner on a tight budget, I often hesitate about whether to replace parts. But a leaking crankshaft oil seal must be replaced, otherwise the engine oil could drain completely, potentially causing engine seizure. I once tried just adding sealant as a temporary fix – it worked briefly but started leaking again after a few weeks. Only replacing it provided a permanent solution, and the cost wasn't high. Those with mechanical skills can even DIY the replacement. Long-term neglect can lead to major repairs like piston ring replacement, which costs significantly more. Regularly inspect oil seals for cracks, and always check the dipstick before long trips. Oil leaks also create messy engine bay stains that are troublesome to clean.
