I've had my 61 plate 1.6 Ti-VCT Focus for two weeks now and when I bought it it was a quiet engine that pulled well. 

This weekend I took it for the weekend to the Cotswolds and it drove perfectly all the way there but later in the day I was going up a mile long hill at 60mph in 5th gear and suddenly I lost power and had to drop to 4th gear and ended up limping up the hill at 40mph. For the rest of the weekend the car drove perfectly but I had a low drumming noise coming from the engine. I got my wife's cousin to look briefly at it and he removed the engine oil cap and I've got lots of air being pushed out from under the cover and oil splatters when I rev. He said that shouldn't happen and we looked at his 2015 Vauxhall Zafira but his is also blowing out a fair amount of air from under the cap too, although not as much mine. 

Have a got a major problem or could it be the PCV playing up?

Looking online last night I'm thinking I need to discount the PCV first and pray that it might just be that. 

I've seen you tube videos showing the valve can stick or the pipe can block or collapse but none showed where the system is on my particular engine, the 1.6 Ti-VCT. Can anybody please show me?

I'm hoping it's nothing more serious as tbh the engine is ticking over nicely and not noisy at all apart from the noise described above. Also my engine management light isn't on either. 

Look at the back of the alternator you will see a pipe that has a slight bend and goes behind the intake that's the crank breather. The Pcv is at the end of that pipe and is plugged into the block. There is limited space in there you can grab it from the right hand side of the intake but be careful once it pops the Pcv can end up on the ground. I would first check the condition of the crank pipe especially at the bend as it swells and cracks. 

Is that it?

No fault codes on my OBD11 reader either. Engine idling nice, not misfiring its just the odd noise and the air being forced out of the oil filler cap when opened. 

Although my older 55 plate Focus also blows out air from the filler cap when opened so perhaps I'm barking up the wrong tree with that assumption. Perhaps all cars do it?

Just came back from the dealer and straight away he said it was the exhaust flexi downpipe that had a tiny hole in it. 

He put on the code reader and, like mine, it came up with no fault codes and he took it for a test drive and said it was running well, which it is. Does anybody know how much one of these flexis are?

Taking it on Wednesday to my trusted mechanic for a second opinion and the fix itself if that's what it is in the end. 

The flexi section is part of the cat on these, and I think they're twin cats as well...very expensive to replace as a whole. 

Depending the type of damage, hopefully you can get away with a welded repair instead of a replacement.  It's not something a Ford dealer would do though, you'd need an indy that does welding or a specific exhaust shop.

As you've only recently bought the car, did you get any warranty with it? 

 

This should do the damage https://www.ebay.co.uk/itm/351351287880

 

My car is a 2011, would that Ebay one be the same? It's says 04-08

7 minutes ago, fladavid said:

My car is a 2011, would that Ebay one be the same? It's says 04-08

You profile has 2006 in it that's why 😂 

Yes I have two Focus. 55 plate and 61 now. 

Any exhaust shop should have a selection of flexi's like that, in various sizes and lengths ready to fit.  

The old one(s) need cutting out first.  Personally I'd prefer to have new ones welded in, clamps just create another area for a potential leak/blow.