Fixing a excessive oil leak

Car stuff Nov 29, 2019

Since the moment I got the car, it's excessive engine oil consumption was rather interesting and annoying.  The previous owner would just top it off every 1200 km and be done with it, which was okay in their situation. The car only had to make it to the next M.O.T. and could fall apart afterwards basically.  
But that wasn't what I had in mind, since this was my first car, and I couldn't fix a better one anytime soon. But I did have a lot of time, "The Google", and a rather strong will to save money in the long run. And of course, experience new stuff and learning things is awesome.
I couldn't look that well in the car, but there was a clear giveaway to where the oil leaked out from - a component attached to the engine itself.

The component in question is a part called the "Positive crankcase ventilation".
I'll try to describe you why this component could leak so much oil, without it being in the engine.  
The main goal if this system, is to remove so called "blow-by" from the crankcase. Blow-by are gases from the combustion chamber, that have leaked into the crankcase through the piston rings.
These gases are contaminating the engine oil, so it's better to give those gases another place to go.
With the blow-by also engine oil get's pulled through the PCV, because that tends to vaporize under the heat, pressure and spinning parts.

Sadly I don't have a good picture from it, since it's buried behind the engine. But it's a picture nonetheless.

The big black part with the cable coming from above is the culprit
The big black part with the cable coming from above is the culprit

To give you an idea of what you're looking at, this is the brand new replacement part:

The new PCV valve and hose
The new PCV valve and hose

You can see the round thing on the other picture as well.  

So far the easy part.  
For the replacement I asked a buddy of mine to help me, since my skills were still lacking, and I didn't know for sure that I could reach it properly on my own.  
He had the tools and car jacks etc., so an easy decision.

Location of the PCV valve, 30-40 cm below the arrow, below the intake manifold (four black tubes)
Location of the PCV valve, 30-40 cm below the arrow, below the intake manifold (four black tubes)
The PCV valve, rather buried under all kinds of cables, hoses, and the intake manifold.
The PCV valve, rather buried under all kinds of cables, hoses, and the intake manifold.
A rather leaky seal, 

Both seals were leaking, but the most obvious bad seal was the lower one.

Sadly I don't have any more pictures from the actual repair itself, it took way longer than expected. Both my friend and I expected that we would need somewhere around an hour, but we ended up fumbling around with it for two and a half hours.
I did take it apart afterwards, and except for a lot old and crunchy oil, it could go for another round with new seals. So I put it aside, for the next time the car needs an excessive amount of oil.  

Membrane (right round thing) pulled from the PCV valve.
Membrane (right round thing) pulled from the PCV valve.

Since the repair, I have only had to top off the engine oil once after ~7000 km, including ~400 km before the PCV valve got replaced but the engine oil not topped off.  
That the engine still needs some occassionally topping off, means that the engine does have wear on the piston rings.
But it's still good for years and years of use.  
I think it's very cool to do such "small" repairs that bring so much improvements in the general running costs.
The savings in oil consumption have already paid for the replacement part plus shipping.

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