106 gti blow-by at oil cap, exhaust cam box

[davie206]

Anyone any idea on what could be causing excessive blow-by in the exhaust cam box? There's no vent in the exhaust cam box, there's a vent in the inlet cam box that is connected to the intake but there's not much blow-by at all at that breather. Problem seems to be at the exhaust cam box. Could it be bad exhaust valve seals

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[Gibbo2286]

I'm not familiar with that model, does it have a valve in the breather system between the crankcase and inlet manifold or maybe the air cleaner box?
If so it may be that faulty, the breathing system is intended to produce a negative pressure in the crankcase and if it doesn't then oil gets out anywhere it can.
It used to be a common problem on BXs.

[davie206]

There's a breather between the inlet cam box and intake. There's no pressure blowing out this point though. All the blow-by pressure seems to be at the exhaust cam box

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[davie206]

Not sure about a valve between the crankcase and inlet manifold tbh it's a head off job to get the inlet manifold off

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[Gibbo2286]

Not sure about a valve between the crankcase and inlet manifold tbh it's a head off job to get the inlet manifold off

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The valve I'm talking about will be in the rubber breather hose if there is one, usually a round plastic item that everybody sees but few know the reason for. On some models it's plugged into the side of the air filter box.

[davie206]

Yeh the breather between inlet cam cover and the intake? That ones fine the pressure buildup is at the exhaust cam side. There's a breather that goes from the sump to the side of the head, I wonder if that's blocked. The cam covers on the c2 version of this engine has a breather for the exhaust cam cover that is connected to the intake unlike the gti engine, so I might just put jp4 cam covers on it

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