Breather pipe

[ASM]

After a few weeks of frustration changing various parts on the S3 it turns out the problem with the bad running was traced to a collapsed breather pipe.

Can you give me any clue as to where this is and what function it performs so I can understand why it's effect caused such intermittent power delivery??

Cheers

[spivvy]

breather pipe runs from air filter to breather on rocker cover .
when i bought a new filter i removed the breather pipe on put a breather filter direct onto the rocker cover

[andyf007]

There's also another one that runs from the other rocker cover to the inlet manifold. This has a one way valve at the rocker cover end.

Andy

[ASM]

and in your opinions would it cause bad running if either were collapsed?

[andyf007]

ASM said:

and in your opinions would it cause bad running if either were collapsed?

In respect to the pipe I mentioned it affects the overall volume and temperature of the air flowing into the engine, but it isn't monitored by the ecu. So if the pipes collapse, air flow will be reduced, but no adjustment will be made to the fuelling to compensate.

The other pipe to the filter doesn't suffer this problem, but both affect the air pressure in the crankcase, which can equally cause problems.

Andy

[ASM]

Thanks, just a bit concerned as changed a few parts recently which seem on the face of it to have solved the problem them only to find it returns unexpectedly. Fingers crossed this has sorted it out?

[mel-S3]

ASM said:

and in your opinions would it cause bad running if either were collapsed?

Apart from the points that Andy mentioned, there is a good chance it may cause oil leaks around the engine.

andyf007 said:

This has a one way valve at the rocker cover end.

Ford recommend that this is changed periodically, can’t remember the exact mileage, it’s in the Haynes Sierra Manual. Only a few quid, may be worth doing while you are on.

[dern]

ASM said:

and in your opinions would it cause bad running if either were collapsed?

I can vouch that the one that runs from the other rocker cover to the inlet manifold will cause bad running if it collapses. You'd need to search quite a way back to find the problems I had as I sold the car 6 months ago so it would be a couple of years back now. Basically my breather pipe collapsed under vacuum because it folded behind the distributor. The symptoms were dramatic kangarooing and an ability to idle perfectly or run on full throttle quite happily. Needless to say this made roundabouts an 'adventure' . It also frequently resulted in wet plugs once the thing had come to an embarassing stall mid power slide.

I took the pipe to ford who matched the part numbers on it against some oil pipe on their database which cost a few quid. I fitted it making sure it wasn't kinked anywhere and never had the problem again.

Good luck,

Mark

[ASM]

Thanks Mark, you have just described the problem exactly right down to the wet plugs, sounds like it might be nailed at last cheers.

[peter m]

The breather pipes are to used to scavenge unburnt mixture that has blown by the pistons, and oil vapour, from the crank case. This is then fed to the inlet manifold or air filter so the gasses are then burnt by the engine, so reducing emissions.

Any leaks in the pipes, due to them splitting or perishing, will reduce the vacuum in the manifold slightly, so at idle the engine will be lean. This causes it to run irratically and kangeroo. I had this problem on my Fiesta, and it took me ages to find it.

If you have these problems, it is wise to check all of the vacuum system, including the brake servo and the distributer vacuum advance diaphram. Any leaks anywhere can mess up the idle.

There should be a description and diagram of the breather system for the V6 in the Haynes manual.

The breather hoses can also clog up with emulsified oil/water, which looks like thick brown gunk. This can occur if the engine has been standing and got condensation inside. Blocked pipes can also cause irratic running.

Phew, these pipes are little devils

[ASM]

Manay thanks for that Pete

[Brentford35]

Sorry to wake up an old post.

I'm after the rubber hose from inlet to rocker cover as mine has collapsed and perished.

Does anyone know where I can buy one from?

Does anyone know the Ford part number?

Does anyone know the sizes as the inlet side seems larger than the rocker side?

Many thanks guys

[phillpot]

Brentford35 said:

Sorry to wake up an old post.

That's quite alright, no need to apologise.Is it the hose from the air filter to the oil filler cap?

Brentford35 said:

Does anyone know where I can buy one from?

Ebay ?

Brentford35 said:

Does anyone know the Ford part number?

I don't think it's a Ford part, and if it were I suspect it would be long since obsolete?

Brentford35 said:

Does anyone know the sizes as the inlet side seems larger than the rocker side?

Measure the thingies it pushes onto? If there is a bit of a difference I reckon one end will stretch a bit or the other squash down so a "nornal" bit of pipe can be used

Edited by phillpot on Wednesday 15th August 04:34

[Maffe]

Picture of the part?
Just charges almost Evert hose on my s3c, most of the them I got from a local dealer. Just needed the size and what what it was going to be used in so the rating for oil/gasoline got correct.