Depends on which seal and which model vehicle, but it involves replacing the bad seal. Rear main seals usually aren't that difficult - though again, depending on the model, it may involve dropping the transmission. Front seals or crankshaft seals involve pulling the harmonic balancer (if you have one), pulling the timing cover (if you have one) pulling the old seal from around the crankshaft and tapping the new one into place.
That would depend on what oil seal you are referring to. There are many oil seals.
replace the seal
There are several types of oil leak sealant for a 1992 Honda Accord. A few of the sealants that can be used are Bar Leak's seal repair, Lucas Oil, and Blue Devil oil leak sealant.
There is only one way. Find the leak and repair whatever is causing the leak. Bad gasket, seal, or broken part, whatever.
To repair an oil leak at the crankshaft on a 1996 Chrysler LHS, you'll need to replace the crankshaft seal. Start by draining the engine oil and removing the harmonic balancer to access the seal. Carefully pry out the old seal with a seal puller or flat tool, then install the new seal, ensuring it's seated evenly. Reassemble the components, refill the oil, and check for leaks before starting the engine.
An oil leak on a 1995 Toyota 4Runner can often be repaired by replacing the damaged gasket or seal. Tightening the oil pan bolts can also fix some leaks.
The cost to repair an oil leak on a 99 Ford Escort will usually cost between $250 and $500 depending on the cause. A worn seal or gasket is much cheaper than a bent pan or a ruptured block.
A 2001 Ford escape differential leak is usually caused by a bad seal. Replace the differential seal. The new seal should stop the oil leak.
To repair a Daewoo Matiz gearbox oil leak, start by identifying the source of the leak, which may be from seals, gaskets, or the gearbox casing. Clean the area around the leak to remove any dirt and old oil. If the leak is from a seal or gasket, replace it with a new one, ensuring proper sealing. For small cracks in the casing, you can use a suitable epoxy or sealant, but if the damage is extensive, consider consulting a professional for a more comprehensive repair.
You probably need to drop the oil pan down, remove the front cover and replace the cover gasket and main seal.
The oil leak is probably comming from the top of the oil pan there is a rubber gasket that goes between the oil pan and the water pumb which would make it look like its comming from the harmonic balancer, try replacing the oil pan gasket this should fix the problem. New answer: There is a small round oil seal / Harmonic balancer seal that fits in the timing cover and the balancer slides through the center of it. That is probley were your oil leak is. Most of the time the balancer itself gets a groove wore in it over time from that rubber seal running on it. You can repair the balancer by buying a Harmonic balancer repair sleeve/ speedy seal. Also replace the front timing cover seal.
Cost of a crank seal leak repair