Oil Leak

[biggles10]

Hi All,

I have a 2003 Fabia estate 1.2 litre twin cam, mileage 133k. It is using oil at an alarming rate 15 litres in approx. 3,000 miles.

It does not appear to be smoking, I have not noticed black smoke from the exhaust and there is no soot around the exhaust exit on the rear bumper. There is oil on top of the gearbox and a streak of oil on the underside that corresponds to this. There is no oil on my driveway so I assume it only leaks when running.

I cannot find an obvious source for the oil leak. The head was off in the summer and the problem has occurred since then, fortunately I do not use the car much.

Can anyone help with the source of the leak?

Thanks

[rum4mo]

I'd be starting by cleaning off that end of the engine head/block joining point and the top of the gearbox, then keep a close watch on it so that you see where the oil is starting to come from, at a gallon per 1000 miles, it should show up quite quickly! By cleaning off, I mean make sure that you turn that area back to dry metal, not just wipe it a bit!

[biggles10]

Thanks rum4mo, I had I go at this yesterday. There is a lot to remove over the gearbox to give access for a good clean, this had put me off doing it before. I think I have found the cause. There was a bolt missing from the coolant manifold on the side of the head. This was the highest point of the oil marks and there was oil in the thread. I think the threaded hole breaks into an oil way. Anyway a new bolt has been fitted, so far so good. The missing bolt went here (photo taken after cleaning):

[biggles10]

Photo did not upload, hopefully this will work....

[Breezy_Pete]

Interesting. I'm sure that threaded hole shouldn't communicate with an oilway.  I may have a look at a spare head I have at home later. 

[biggles10]

Thanks Wino, it would be good to know if there is an oilway in that area. I assume the connection with the oilway is small otherwise a lot more oil would have been coming out if the oil is under pressure.

[Breezy_Pete]

I wonder if it goes into an oil drain as opposed to an oil feed, so no pressure. Wouldn't expect it to go into either by design though.

Couple of hours time I can have a look.

[Breezy_Pete]

Well I'm still baffled.  That tapped hole does go through into another drilling (illustrated by the white wire-tie going through), but it's one of the headbolt drillings, and not the one that's associated with the oil feed up into the head.  In the picture below most things are colour coded with text of the same colour explaining what's what. Only exception is the green arrows with white borders which are three headbolt holes that are oversize compared with the other five.  The lower two in the picture are oversize because locating dowels poke up into them from the block, the oil feed one is bigger to allow flow round the outside of the bolt up to drillings connecting it to the two main left-right oil galleries of the head.

 

I would expect the headbolt head/washer of the bolt-hole in question to seal the top of the ('white wire-tie') drilling, and I would have thought that the headbolt would go into a blind tapped hole in the block, so no oil would come from that way.  Either one of those assumptions is incorrect, or there's a casting void or crack or something that's allowing an undesigned connection between that headbolt hole and somewhere oily.  ???

 

 

 

 

Edited 25 April, 2017 by Wino