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Oil in inlet system, what is the black valve on the TIP?

Discussion in 'A3/S3 Forum (8L Chassis)' started by Prawn, Feb 8, 2008.

  1. Prawn
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    Prawn My other car is a MINI!!!!

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    Hi guys, my PCV is blowing a load of oil into my TIP, to the point where my FMIC has oil inside the core!

    I noticed that where the vent leaks the rocker cover, it goes into a splitter, and 1 side goes back to the TIP via a black round valve (letting oil through) and 1 side goes into some other piping down beneath the inlet.

    What is that black round component? can it be causing the excessive oil into my induction system?

    Could I just remove it and plug the two holes? I see no advantage in having my crank case vent into the TIP pre turbo, and its not helping me seal my boost pipes having them full of oil.

    Any ideas would be awesome.

    Thanks

    Nick
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  2. Jay
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    Jay Member

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    Are you having to top up alot more due to this?
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  3. Prawn
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    Prawn My other car is a MINI!!!!

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    Well, I think I may have been slightly wrong back then about the oil issue!
    My pcv is venting oil back into the inlet, but I think it's fairly minimal really.

    The reason my core was full of oil was due to a totally ruined turbo!
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  4. HTC
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    HTC Active Member

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    You will always get some oil in the boost pipes I'm afraid unless you go for a catch can setup. I have some oil in my IC.
    The round saucer thing is the crankcase ventilation pressure valve and separator (most people call them PCV or positive crankcase valve). It acts "or attempts to" allow only enough vapour into the inlet to ease pressure in the crankcase which naturally builds up in any engine.

    It connects to the block and inlet manifold via a tee peice under the inlet which also acts as a one way valve I believe, but don't quote me on that.

    Under vacuum, air is drawn towards the inlet manifold from the block and TIP. Under boost air is sucked into the TIP from the PCV and block, but the tee valve should prevent positive boost pressure from reaching the PCV and block that would pressurise the crankcase.

    If you are getting excessive oil then I suspect there may be a problem with the tee valve , if it is a one way valve. Also a build up of goo in the breather system will act to thin the internal diameter of the pipes. This can allow oil to be drawn up via capillary action.

    So, inspect the pcv and tee valve and state of the pipes. If you still aren't happy, get a catch can fitted.

    You can't plug the breather holes as the pressure in the crankcase would build up and force oil out of all the gaskets in no time. By law car manufacturers have to vent the hydrocarbon rich gasses back into the inlet for them to be burnt and delt with by the charcoal canister. Not sure what the legal position is for changing that yourself. You may have seen those small air filters some people use instead.
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  5. HTC
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    HTC Active Member

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    Arse, and I just typed all that for ya...........lesson over for today!! :)
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