oil leak on 2001 Toyota Corolla

I have oil leak under the hood. They are saying it is possibly engine value covers. What happens if I don't stop this leak and how expensive is it to repair?

Asked by for the 2001 Toyota Corolla
It takes .8 hour to replace the V/Cover gasket and plug tube seals ($35 parts) if its not been done recently the valve clearance should be checked while the Valve Cover is off.
1 more answer
If you don't address this leak you will have to watch the oil level, So it doesn't get too low and you can check the repair estimate here put in you vehicle's info and choose valve cover replace