How to replace a crankcase vent hose in a 2002 Ford Focus

The Ford focus was introduced in 1998 and soon became a best-seller, from its introduction all engine variants up to 2005 worked on a positive crankcase ventilation (PCV) system, this was a way of reducing harmful emissions to the environment. Any gases not burnt in the engine would be drawn through a valve and hose, then back into the inlet manifold and re-burnt with the fuel and air mix. One of the key components of this system is the crankshaft vent hose; timely replacement if damaged will save a lot of money in garage costs.

Park the vehicle in a safe place to work, apply the handbrake fully, open the bonnet and let the engine cool down completely, you will be working near the manifold and have a risk of being burnt. The procedure would be easier if you have access to a ramp or pit.

Locate the PCV valve; this is found just below the exhaust manifold attached to the oil cooler. Gently pull the PCV valve out of the oil cooler with the hose still attached.

Remove the PCV valve from the hose. Make sure the valve is in good serviceable condition. If not, or if the vehicle has done more than 50,000 miles, this valve should be changed. Pull the shorter hose off the metal breather pipe located just below the thermostat housing.

Trace the length of hose along toward the inlet manifold, remove any hose clips as required. At the bottom of the inlet manifold pull the hose off the spigot and pull the hose clear, make sure you note the path the hose takes.

Install the new breather pipe along the same route the old one came from, push the hose end on to the inlet manifold spigot and re-connect any hose clips. At the other end of the hose, reconnect the PCV valve and ensure a tight fit. Insert the PCV valve back into the oil cooler and ensure the rubber grommet in the oil cooler where the valves fits into is in good condition. If damaged, replace it prior to re fitting the PCV valve.


A ramp or pit would make the job easier.


Make sure the car has cooled down before starting work.

Things You'll Need

  • Screw driver
  • Pliers
  • Spanners
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About the Author

Jenny Roberts has been working as a ghost writer since early 2011. She has published numerous articles on health, fitness and diet, travel and a variety of other subjects. She is a qualified accountant and teacher.