What does low PCV indicate?
A decreased PCV indicates anaemia. Further testing may be necessary to determine the exact cause of the anaemia. Conditions that can result in a low PCV include. Bleeding. Nutritional - iron, vitamin (e.g. B12 or folate) or other mineral deficiencies. via
Do I really need to replace PCV valve?
If you can hear a metallic rattling noise, it's likely in good working order. If you do not hear anything when you shake the valve, it is likely that it is no longer opening and closing like it should. You may be able to clean out the valve to get it functioning again, or you may need to replace it. via
How do you clean PCV? (video)
How long can I drive with bad PCV?
If your PCV valve is badly damaged, it might be risky to drive any longer than 12 hours. However, you should drive no further than that as long as you should if the damage is not extensive. With the rough PCV valve hose, these excesses are transferred. via