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Discussion Starter #1
Hi all,
I have been trying to sort a few issues with my engine and removed the sealing plug behind the dipstick tube on the back of the block as it was leaking oil. Upon removal I found that it had a hole straight through the centre. I find it strange to have a sealing plug with copper washer having a hole in it. Does anyone know what it is for or even if it is supposed to have a hole? I have tried to look in the hole in the block and see what it is for but I cant get a clear view around the dipstick tube and that won't come out without removing the DPF. I have tried searching online for images of it but can't find anything useful.
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What model year? There are to plugs in that area that I’m aware of. One is for draining the block of cooling liquid when replacing the water pump, and the other one is a “tell tale hole” from the water pump house. I think that your plug is from the water pump house (tell tale hole)..If it is, your gasket between the water pump housing and the timing case are leaking, which is not common. The other gasket on the water pump is from the coolant circuit...
A picture will confirm what type of plug this is...
 

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Discussion Starter #3
Hi,
Thanks for the reply. It is a 2007 model year. Pic of location of plug attached. It is the larger of the two plugs. Hard to show it clearly as the dipstick tube is in the way.
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It look like slightly above the two plugs I’m referring to...!? I don’t know what the hole/plug in your picture is...
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Okay, then it is the tell tale hole. Replace the water pump. The plug to the right is the coolant draining plug I wrote about earlier...
 

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I'm with Silenhag, change the pump. (y) It certainly is unusual for oil to come out of that hole. Actually nothing should come out under normal circumstances. On this engine the water pump is internal (inside the engine) and if/when it fails and leaks, the design allows for a handy and visible route to the outside via that hole. (For plumbers and heating engineers it's the same thing as that tank overflow pipe near the front door that everyone has but don't realise they do) only in this case it doesn't necessarily work!

Unfortunately (add your theory here) it is more common for coolant leaking from this internal water pump to choose to pass by one of the two external pump seals and end up in the engine.

In your (rare) case it looks like the seal between the pump and engine is allowing oil to escape from the engine into the water pump drain space and out through the drain hole. (A banjo union/pipe on early engines). It is unusual but it isn't part of the pressurised oil system so it won't be pumping out to death. I would change the water pump anyway and check that where the pump-seals seat is ok. You should check for a blocked breather on the rocker cover and crimped PCV pipework in case there is any extra internal engine pressure.
 

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Discussion Starter #10
Thanks guys. Looks like further investigation is required......and a new water pump. Still don't understand why VW would put a sealing washer on that plug when it has hole in it:unsure:
 

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I reckon If they drill a hole in the plug they want any coolant leaking to come out of it, not dribble messily around the bottom of the plug threads.
 
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