understanding the 'oil vapour recovery' system (oil breather)

[karatemaserati]

so one of the advisorys i had in the report when buying the car was there not being any suction in the oil breather system, which i was assured was pretty minor.

before i take it apart and have a look i just want to make sure iv understood how the system works if anyone knows if this is right?? oh snd what does the mystery pipe do??

 

[conaero]

All I know is that this is a service item, every 4 years on the GTS so I would image it acts like a filter and basically clogs over time. You could try clearing it out but you might introduce crud into your oil system so I would simply replace the unit (item 1) its £100 plus VAT from Eurospares:

http://www.eurospares.co.uk/searchResult_one.asp?S=585043002&TM=3&TMo=698&TA=1&TB=41466

Item 9 looks like a non return valve, so would also look at cleaning this out too.

 

[Rex B]

He goes a brief description from the manual.

Blow by gases that pass the piston rings go into the crankcase and then rise to the cylinderhead where they pass via the cam breather pipes to the cam sump where oil contained in the vapour seperates, some drains back into the sump and the remainder vapour 1/ under no boost conditions passes via non return valve 25 on the drawing into the into the intake manifold and then 2/ under Boost conditions pass via non return valve 9 into the air cleaner.

Rex B

 

[karatemaserati]

ah thanks, so i was kind of right

could you tell me what page from which manual that is please im having difficulties finding it on the electronic copy iv got

 

[Rex B]

HI

Electronic Manual - Engine - Fuel Supply -pages 62 and 63

Rex B

 

[karatemaserati]

brilliant thanks! that is exactly what i need

 

[MUC3200GT]

All I know is that this is a service item, every 4 years on the GTS so I would image it acts like a filter and basically clogs over time. You could try clearing it out but you might introduce crud into your oil system so I would simply replace the unit (item 1) its £100 plus VAT from Eurospares:

http://www.eurospares.co.uk/searchResult_one.asp?S=585043002&TM=3&TMo=698&TA=1&TB=41466

Item 9 looks like a non return valve, so would also look at cleaning this out too.

is the oil breather a service item (its just oil vapour - so what to filter) or is the fuel vapour canister the maintenance item ?

 

[karatemaserati]

anyone know the vapours only go to the manifold while the engine isn't boosting and not all the time??

 

[MUC3200GT]

This I was wonderin as well ...but as item 25 is a valve I would assume that the vapours can go in the manifold only when there is no pressure and the valve prevents pressure escaping fom the manifold. And when the manifold is pressurized the vapours go through valve 9 in the upstream behind the air-cleaner

 

[karatemaserati]

thats sounds right as i took the pipe off to check that valve 25 wasnt blocked and there was strong suction from the manifold all the way to the vapour recovery box and the NRV was operating correctly.... which leaves me to wonder where they got the 'no suction in oil breather system' from

 

[karatemaserati]

i have been informed there should also be suction comming from where you lift the oil dip stick... which there deffinatly isnt. and the valve concerned with this is no 9

 

[MUC3200GT]

this valve needs some suction to open, I tried to check one and I thought it is broken, but some more suction opened it finally. Now I feel its opening also with lesser suction. Of cause this is no proof and I am not 100% sure about the suction apllied in inital attempt but maybe it hanged a little bit. Also if there would be a (temporary) hole somewhere in the hose to the valve or somewhere else in the whole intake manifold the suction could be lesser than expected.