MajorCommonEngine

Ford Focus: PCV breather diaphragm rupture - whistle, oil use and seal damage (XR5 Turbo / ST225, B5254T3)

PCV breather diaphragm rupture - whistle, oil use and seal damage (XR5 Turbo / ST225, B5254T3) is a common engine fault on the Ford Focus on the 2006–2011 cars, and we rate it major. Putting it right costs ≈A$460 to ≈A$1,380 at independent workshop rates, shown as an approximate guide in Australian dollars. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 37 documented faults on the Ford Focus.

Vehicle: Ford Focus
Engine: 2.5L
Years: 2006–2011
Fuel: petrol
System: Engine

This page covers the Ford Focus as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Ford Focus faults37 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Turbocharger or PCV / oil separator yet. We would rather show none than show a picture of a different part.

What goes wrong

On the XR5 Turbo's Volvo-sourced 2.5-litre five-cylinder, the crankcase breather (PCV) diaphragm in the oil filter housing ruptures. The giveaway is a high-pitched whistle that rises with engine revs, plus soft boost in low gears, high oil consumption and blue exhaust smoke. Driving on with it ruptured pressurises the crankcase and can blow out the camshaft or crankshaft oil seals - at which point the timing belt, and in bad cases the clutch, get oil-soaked and the bill multiplies. Short-trip, low-mileage cars are the most prone. The fix itself (a new oil filter housing assembly) is moderate money if caught early.

What you would notice

High-pitched whine or whistle that rises with rpm
Weak boost in low gears
Blue smoke from the exhaust and oil consumption between services

How to check it

Where to look. Oil filter housing on the front of the 2.5-litre engine, behind the air filter housing

Start the engine and listen: a rising whistle with revs, from the engine rather than the intake, is the classic sign. The known party trick - the whistle stops when the dipstick is pulled while idling, because that releases crankcase pressure - is something you can do at the viewing in ten seconds. Check for fresh oil weeps at the front (timing belt end) and back of the engine, and ask when the oil was last topped up. On the test drive note whether boost feels flat in first and second gear. Walk away pricing in seal, belt and clutch checks if the whistle is present and the seller calls it 'just a noise'.

Parts involved: Turbocharger, PCV / oil separator.

What it costs to put right

≈A$460 to ≈A$1,380 at independent workshop rates, shown as an approximate guide in Australian dollars. That is for this job on its own, not for the car.

An estimate, converted to Australian dollars, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Has the PCV diaphragm or oil filter housing been replaced, and when?”
“How much oil does it use between services?”
“Any oil leaks at the timing belt end?”

Now check the Ford Focus you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car still has money owing on it, has been written off or reported stolen, what kms it showed in past sale ads, whether it has had accident repair claims and what it is worth today. That comes from the official records for that plate. Enter the plate and its state for the A$17.90 Vehicle Check, or the full history from A$24.99.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

AustralianCar.Reviews 'Recalls & faults: Ford Focus XR5 Turbo (2005-11)' (PCV diaphragm rupture, with OEM Denied)
JXL Performance 'Ford Focus ST Mk2 (ST225) Buying Guide' (turbo whistle, oil consumption)

Ford Focus buyer questions

Is pcv breather diaphragm rupture - whistle, oil use and seal damage (xr5 turbo / st225, b5254t3) serious on a Ford Focus?

We rate it major and common on the Ford Focus. On the XR5 Turbo's Volvo-sourced 2.5-litre five-cylinder, the crankcase breather (PCV) diaphragm in the oil filter housing ruptures. The giveaway is a high-pitched whistle that rises with engine revs, plus soft boost in low gears, high oil consumption and blue exhaust smoke. Driving on with it ruptured pressurises the crankcase and can blow out the camshaft or crankshaft oil seals - at which point the timing belt, and in bad cases the clutch, get oil-soaked and the bill multiplies. Short-trip, low-mileage cars are the most prone. The fix itself (a new oil filter housing assembly) is moderate money if caught early.

How much does it cost to fix on a Ford Focus?

≈A$460 to ≈A$1,380 at independent workshop rates, shown as an approximate guide in Australian dollars. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Ford Focus years are affected?

Our research records this fault on the 2006–2011 Ford Focus. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.