My sponge was rotten to the touch and full of oil. So what is the role of this valve in the engine!?

its written in earlier posts on this very thread....

the sponge condenses the oil out of the engine breather mist to reduce the risk of contaminating the air filter element
when you buy the air filter from the ford parts counter they give you a new foam bit each time....  but no one buys it there, they'd rather have a cheap one that doesn't filter the dust as well as a ford one, and thus never understand the foam should be replaced every 12k miles

a disgusting blob of rotten foam blocked with 60k miles of engine breather filth will actually cause far more engine wear - its been nearly 50 years since the law mandated engine's recycle the acidic oily filth we used to spit at the floor externally - there's also a valve that helps control this breather system (PCV - positive crank case ventilation).  As pistons go up and down they displace below the pistons, the same amount of air every turn of the crankshaft as the (1.6 ltr) badge says on the boot lid... so there's a lot of movement of air going on - this whips up the oil some of which becomes a mist, add in cold start over enrichment fuel residue, condense moisture from too many short runs, combustion gas acids and such filth all needs to be got rid of via the breather system going back in through the air box...

a dirty blocked bit of foam can easily be the difference of an emission failure during your MOT - and is indeed why changing the dirty hydrocarbon impregnated filthy engine oil will also vastly reduce the emission numbers...

4 hours ago, Zalmoxiss said:

So what is the role of this valve in the engine!?

This thread was started 20th March 2013. It has now reached two pages long, but if you go back to the start and read all the replies then it should answer all your questions.