IEnumberable<Car> list

list.RemoveWhere(r=>r.Year > 2000)

list = list.Where(r=>r.Year<=2000)

public static IEnumerable<T> RemoveWhere<T>(this IEnumerable<T> query, Predicate<T> predicate)
{
    return query.Where(e => !predicate(e));
}

MyList.RemoveAll( p => p.MyProperty == MyValue );

list = list.Where(car => car.Year <= 2000);

public static class CollectionExtensions {
     public static ICollection<T> RemoveWhere<T>(this ICollection<T> collection, Func<T, bool> predicate) {
        List<T> toRemove = collection.Where(item => predicate(item)).ToList();
        toRemove.ForEach(item => collection.Remove(item));
        return collection;
     }
  }