Commonly Encountered Problems with a Volvo S40 PCV Hose
Fuel, being a very expensive resource, needs to be used wisely. It is also recommended that every drop of fuel should be used and not wasted. The PCV is the main part for this type of job. As fuel burns, it emits unburned fuel vapor and other materials which are harmful to the environment. What the PCV Valve does is it takes these vapors and reroutes them into the intake manifold for further usage, a process that passes through a PCV hose. There are problems related to a bad PCV hose, and they are listed below:
Contaminated air filter
A product of a stuck-close valve because of blow-by gases, contamination occurs when gasoline builds up in the hose. Oil tends to travel up the clean air hose and into the air filter. This contaminates the air filter, or breather, and can cause problems for you and your car. Some of these problems may include issues in drivability and when traveling.
Engine light becoming lit
This is usually a case for suspicion since a PCV hose does not cause this. There is usually something wrong with your PCV if this happens, and that something wrong is a vacum. An area of vacum within your PCV valve or hose occurs when there is air leaking into the system. This causes the 'Check Engine' light to illuminate. Take out the PCV valve with the hose still attached to it if you are to check it for leaks and cracks. If there is nothing wrong, you should look at the vacum hose to trace the cause of the problem.
Another problem with the PCV valve and its hose is the varnish deposits. These are contaminants that, along with dirt and gum deposits, line the passage ways of the hose. It can choke the hose and the valve. If you experience rough idling, hard starting, engine stalls and increased emissions, then you might have a PCV hose problem. If this problem continues to persist for you, you should consider getting a replacement as soon as possible.
Wrong PCV valve
While a PCV valve will never have a problem using the same hose, it will always cause a problem if it's not for the specific make or car model. A PCV valve is always made according to the needed specifications of a car. If your car has a wrong PCV valve installed on it, it will cause a faster buildup of sludge in the crankcase, causing even more problems for your engine.