My 98 Sentra has 100,000m on it. It has had oil leakage problem for a long time - the leakage happens in the main tank area bacasue I can see some oil close to the alternator;and I also found a lot of black dirts at the end area above muffuler. Garage told me there were dirts because the engine was weak and would cost $1,000 to rebuild the engine. The oil leakage would cost $600 to fix. Any suggestions as far as whether worth reparing it or how to fix the car? Any response will be appreciated. Thanks!

 

on those 1.6L on the sentra the crank seals like to go bad around that mileage cause i replaced mine after i was going through two quarts of oil a week ill take a look at that first cause that could be your oil leak or possibly your valve cover gasket is leaking and getting onto your alternator.