When you take your car to the repair shop, and you ask them to do routine service, including replace the PCV valve, you might be told, “Well, nothing to worry about; your car doesn’t have a PCV valve; there’s nothing you have to do”. Well that could be deadly for the engine in your car.

Now true, the old traditional PCV valve, that you unplug, and you shook it to see if it rattled, well they probably, in most cases don’t exist anymore. But, all engines have to breathe. The crankcase gets full of fumes from the combustion process; those fumes build pressure inside the engine. And if you don’t get rid of that pressure, it blows seals and gaskets right out of the engine. So how do they do it today?  

Well, most cars today have something like this: this is a fixed orifice tube. Now we can see this over here is pressed into this valve cover. It is replaceable, but in most cases it can simply be cleaned. And it HAS to be kept clean. You can see the size of the hole on the end of it; it’s very small; it doesn’t take much to clog it up. So make sure that the shop that you use checks the crankcase ventilation system; don’t specify PCV. You want the crankcase ventilation system to be tested, to make sure that it works properly.

Now on some cars they’ll use more elaborate systems, like this one here. Now this is a system that uses various vacuum hoses and different things to control the pressure inside the crankcase. Now over time, what happens with these is that they get full of condensed oil. And what we have is something like this, where you can see that the oil just runs out of it.

Now, once that happens, when it gets clogged up with oil, you can build so much pressure, that it starts to damage seals in the engine. Or in some cases, it will suck the oil out of the crankcase, into the combustion chamber, and an engine will run dry on oil. And of course that means that if you don’t shut it down immediately, you’ve just killed your engine. So again, regardless of the type of crankcase breather system your car has, it is has to have regular, routine maintenance, and must always work properly or you’re going to have damage to your engine. And if you have a question or comment, drop me a line. Right here, at MotorWeek.