Blocked crank case breather on petrol BXs.

[Mothman]

Went down to Malcolms yesterday and decided to check out the crank case breather which is fitted inside the oil filler tube. The 16TGS wasnt running as well as she should have and i found out why.



The tube looked horrible and felt considerably heavier than it should have.



The central section is removed by inserting a rod, slightly narrower than the base of the tube and poping it out from the bottom. What a horrible mess!!



You can see the central tube, and the wire mesh is thoroughly blocked up.



The central tube with the mesh removed.



You can see the tube without the central mesh.



Remove the pin that holds the mesh together. Its either in one piece or two, in my case two.



Then everything is cleaned in petrol.



There, looking much better.



All rolled up and ready to put back.



All you need to do is push down at the top till it clicks back into position.



Like this.



Then refit. Yoy may have to cut the Citroen clips when you come to remove the tube and replace with jubilee clips. When the crank case breather is blocked, it allows moisture to get into the carburettor which then affects performance. I dont think mine had ever been done before as it was so filthy. The car now performs noticeably better and there is no smoke/moisture coming out of the exhaust at all. I would reccomend that anyone who has a petrol BX do this. Not sure if its a similar process with the BX 14s but this will work for all other petrol models i believe. Job took about half an hour and is well within the abilities of most BX owners. Many thanks to Malcolm for his help here.

Andy

[Way2go]

One of those "out of sight, out of mind" jobs! Useful photo record/procedure given there.

[BXImage]

Great job!
On my BX this mesh is completely removed, luckily I got one from donor. If mesh is heavily damaged (rusty), could it be changed with for example wire mesh that is used for dishes - sponge wire? Since I was missing mesh in the oil filler cap too, I used a piece of sponge wire instead.

[Tinkley]

That sounds like the filler tube has been replaced before, as the replacements do not come with the mesh as far as I know....

Mine too has no lower mesh just the one in the filler cap. In fact the speed of oil fill can tell you if the lower mesh is blocked. If it backs up with only low to moderate flow the mesh will be suspect.

[citronut]

In fact the speed of oil fill can tell you if the lower mesh is blocked. If it backs up with only low to moderate flow the mesh will be suspect.

i dont think this could be the case as the mesh is not in the oil in flow, but between the filler funnel and the outer filler neck body,

the usual cause of slow filling is more likely to be the rubber filler neck has collapsed, because either the plastic filler neck is tilted forward/tightened onto the rubber cotton reel mounting, or the mounting has weakened or broken

any of these situations will cause the rubber filler neck to fold over on its self

regards malcolm

[Kaapelimies]

In Finland they adviced (from the importer) to completely remove the mesh, since the oil/water mixture getting there gets frozen and blocks the breather efficiently, and the result is your BX pukes all the oil out from the engine when it's very cold.