hi there have just started to have a problem with my 06 plate 2.5 focus st !! a squeeking noise started the other day when the engine was running and when i switched it off theres a hissing air leak noise !!anyway i noticed that the plastic breather pipe on the front of the engine was split so ive replaced that with a new rubber version !!!aahhhhhh noise still there so ive had another look 2nite and found that there is a massive vacum being created in the motor !! if i remove the oil fill cap or the breather the vacum is released and the noise goes away !! i just wonderd if anyone eles has come across this could it be the pcv playing up help please

 

Yes, you need to change the oil filter housing. very easy job. has the breather built into it

 

As above, oil filter housing diaphragm has split, really common fault on them!

 

cool thanks guys !!

 

Newer type are modified from the one you have fitted and shouldnt happen again !!

 

Hi. Have had the same problems with my 06 st. Found the info on hear very helpful. oil diaphragm has gone £130 + vat from ford next day