There should be no issue in reusing new rubber valve cover gaskets. Since there are only a few weeks old and you didn’t use sealant, you should be able to reuse them.Click to see full answer. Just so, how often do valve cover gaskets need to be replaced?When running your vehicle, the valve cover will have to do its job and keep the oil from leaking out. Most of the gaskets on your car last anywhere from 20,000 to 50,000 miles.Secondly, are cork gaskets reusable? Cork can be completely reusable. I have a set of cork valve cover gaskets on a Y-block that I put on 20 years ago. Still good. Pull the valve covers from time to time to check the valve lash. Just so, do I need to replace valve cover gasket? There are no maintenance requirements for a valve cover gasket. It only needs to be replaced if it leaks. Symptoms of a leaking valve cover gasket include oil drops under the engine, burnt oil smell under the hood and visible traces of oil coming down the engine.What can a leaking valve cover gasket cause? Engine is running rough and causing misfires Sometimes when oil leaks from a valve cover gasket it leaks all the way down to the spark plug galley and eventually seeps inside the spark plug tubes. This will cause a misfire or reduce engine performance. It can also cause a fire under your hood if it goes unrepaired.