T4 Oil Leak

[JerryXD]

Hey guys,

I own a 98 S40 T4 with around 118k miles on the clock. It was serviced about 4 months ago and since then (around 2k miles) it has lost a lot of oil. I had to top it up with about 2 more litres the other day. After looking at the top of the engine I can see oil pooling up, I'm pretty sure that it is on the right side. The first 2 images show what the oil looked like when I first inspected it. I then soaked most of the oil up (picture 3) and after a few days of running, I inspected again (picture 4). This kind of gave me a few ideas of where to look, but I have a few questions first.

The first question is what is the hole between the two spark plugs in picture three? it seems like there should be something attached, and there is a bolt hole next to it. I have had a look around and I can't see anything obvious.

The second is that it seems to me like it could be the black (I guess breather) pipe in the middle, could this be leaking?

I have very little experience with cars, so I may be totally wrong here, but if someone could point me in the right direction I would appreciate it.

[pierremcalpine]

Oil pooling in that location is usually just spilled oil from the last time someone topped up. Track your oil leak from under the engine upwards. Most common places are at rear of engine (the turbo return pipe) and on the right hand side in behind the timing belt ( vvt gear or cam seal).

[V40T4R]

Maybe the oil fill cap gasket, it becomes brittle.

[3rk5]

My V40 has the exact same problem. I also think that it somehow might come from the hole in the third picture. I tried cleaning up the oil on my car and that hole was half full again after couple of minutes of idling. I didn't see any oil anywhere else. Luckily the leak on my car isn't nearly as bad as yours, I haven't had to top it up yet. I had another leak in February this year and replaced the cam seals and rocker cover gasket, so I know these aren't leaking on my car.

[Ginga]

Usually the valve cover is only a cover.
In case of this engine family, this cover holds the actual cams in place.

That's why its fixed with lots of bolts!

The thing with those leaks is that when serviced, the seal needs to be done with some sort of anaerobic gasket.
Volvo sells it, of course...

This liquid gasket is used in a thin layer, curing only in zero oxigen conditons. When cured it helps those parts to work as one structural piece.

Using any other type of liquid or lacker will probably result in it failing to seal the engine properly. And then oil stars coming out from those places, specially that hole between 3 and 4 cylinder...

[Ginga]

Reassembly will be something close to this:
https://www.youtube.com/watch?v=qwenN6MKe8A

[V40T4R]

So I checked mine, completely dry...in fact I don't understand the purpose of that hole.
If it's some crack, I could make a thread and plug it using thread sealant like loctite 577
Just a guess?

[Ginga]

Originally Posted by V40T4R

So I checked mine, completely dry...in fact I don't understand the purpose of that hole.
If it's some crack, I could make a thread and plug it using thread sealant like loctite 577
Just a guess?

I've read one guy who plugged it and get some vacuum lines "blown" in the process. Not sure why that whould happen.
My advise, re-seal the head cover with proper products!

[Ginga]

Problem solved?

[960kg]

To help shed light on that hole .......if you look carefully there is some type of small core plug in the hole which of course will leak as the steal metal plug and alloy head expands and contracts at different rates.

On the white engine block etc. there are NO core plugs fitted as the whole thing is alloy.

Core plugs on a cast iron block are means of getting at parts or oil ways within the block to either drill them in the first place or keep them clean or in the case of the old Jaguar XK140 block to get out old rusty snapped head studs which did rust because of the stud in the water jacket. In time most core plugs used to leak.

I believe in another model this hole in the alloy head of the white block was used for something else hence that small plug and why it leaks.






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