[lvb125]

Before deciding to do anything with my oil leak, I decided to inspect the engine.

The pictures I took:









I suppose VCG is leaking. What about the large oil spot on the valve cover in the first pic? it is in the middle of the passenger side, right next to washer fluid fill. And how about the front of the engine, in the third pic?

Also checked the exposed head bolt (4th pic), is there any sign of snapping off soon?

[Three_thirty_I]

It almost looks like it's coming from higher up. Try and remove the grey engine cover - easy to remove. Just firmly lift it up, you will feel it slowly come free, then just gently slide it out and off. I suspect it might be leaking at the Valvetronic motor gasket. I would also suggest cleaning any traces of oil and then monitor it to see where the oil leak starts again. Valve cover gasket is definitely a possibility, and also things like the oil filter housing gasket (that you would usually see signs of oil leaking below it, or in your coolant). While you have the grey cover off, check the Eccentric shaft sensor plug for oil - that gasket can fail too and result in a damage to this sensor.

[AdamN52]

That first pic looks to me like some oil was spilled when adding oil and flowed down the valve cover.

Take off the VC and see what it looks like around the fill cap. Valvetronic gasket can also leak which I think (hard to tell from the pic exactly where we're looking) is right above where your leak is.
It's not too difficult to replace - and you have to take it off if you're going to do the VCG anyways. Think I got one for like $30

[Three_thirty_I]

Look at this pic below. The first pic above is close in between the window washer filler and the expansion tank in the pic below. The Valvetronic motor is that cylindrical device just above the window washer filler in my pic, and between coil packs 3 and 4. And quite rightly so, the oil filler cap is in the same general area, so it is very possible that there was some spillage, or that the oil cap gasket is leaking a bit which it does seem to tend to do causing some weeping around it.



Hope this helps.

[AdamN52]

Originally Posted by Three_thirty_I

Look at this pic below. The first pic above is close in between the window washer filler and the expansion tank in the pic below. The Valvetronic motor is that cylindrical device just above the window washer filler in my pic, and between coil packs 3 and 4. And quite rightly so, the oil filler cap is in the same general area, so it is very possible that there was some spillage, or that the oil cap gasket is leaking a bit which it does seem to tend to do causing some weeping around it.



Hope this helps.

That's very helpful - I would think it's very likely then that the first leak is due to spillage around oil cap

[Three_thirty_I]

It is very possible! In fact, just recently I had the engine cover off to inspect for oil leaks and there was already quite a significant mess from just oil weeping around the oil filler cap gasket. I should actually just replace it, but at the time I pulled the entire cap off including the rubber gasket, and thoroughly cleaned them with soapy water. I also cleaned all the traces of oil on the valve cover and where the gasket fits. So hopefully it will stay clean for a while. It's important to prevent oil from leaking and getting to the coil packs, and of course the eccentric shaft sensor.

[lvb125]

Originally Posted by Three_thirty_I

It is very possible! In fact, just recently I had the engine cover off to inspect for oil leaks and there was already quite a significant mess from just oil weeping around the oil filler cap gasket. I should actually just replace it, but at the time I pulled the entire cap off including the rubber gasket, and thoroughly cleaned them with soapy water. I also cleaned all the traces of oil on the valve cover and where the gasket fits. So hopefully it will stay clean for a while. It's important to prevent oil from leaking and getting to the coil packs, and of course the eccentric shaft sensor.

Thanks for your info! I ll open the cover to see under this weekend. Actually thinking my eccentric shaft sensor may have gone, as I m getting 13l/100km (about 18 mpg) and feel the delay in throttle response.

[Three_thirty_I]

Originally Posted by lvb125

Thanks for your info! I ll open the cover to see under this weekend. Actually thinking my eccentric shaft sensor may have gone, as I m getting 13l/100km (about 18 mpg) and feel the delay in throttle response.

When last did you clean the MAF sensor, Vanos solenoids etc? Also worth resetting the throttle adaptations every now and again. What sort of driving are typically doing? That's not massively high fuel consumption if it's a fair amount of town and stop/start driving, but definitely way too high if there is a good mix of open road driving!

[lvb125]

Originally Posted by Three_thirty_I

When last did you clean the MAF sensor, Vanos solenoids etc? Also worth resetting the throttle adaptations every now and again. What sort of driving are typically doing? That's not massively high fuel consumption if it's a fair amount of town and stop/start driving, but definitely way too high if there is a good mix of open road driving!

I ve only had the car for a short while. The previous owner had done all service at the dealer, I didn't see record of any of these tune up work. About two years ago there was a misfire and dealer changed all coils (interestingly they didnt do plugs). Around the same time dealer reported VCG leak, but the owner didnt bother to pay to have that fixed.

I d say my driving is about half/half between stop/start and highway. Definitely not hitting redline all the time. Interestingly the trip computer keeps telling me around 11.5L/100km.

Did the press-on-throttle-for-30-seconds trick (thats the throttle adaptations resetting I suppose?) and felt little improvement for throttle response. I also feel the car should pull harder, but that may be subjective.

[Three_thirty_I]

Originally Posted by lvb125

I ve only had the car for a short while. The previous owner had done all service at the dealer, I didn't see record of any of these tune up work. About two years ago there was a misfire and dealer changed all coils (interestingly they didnt do plugs). Around the same time dealer reported VCG leak, but the owner didnt bother to pay to have that fixed.

I d say my driving is about half/half. Definitely not hitting redline all the time. Interestingly the trip computer keeps telling me around 11.5L/100km.

Did the press-on-throttle-for-30-seconds trick (thats the throttle adaptations resetting I suppose?) and felt little improvement for throttle response.

The typical service intervals are far apart, so the onset of sludge is something to be concerned about in general, and things like the Vanos solenoids are usually affected. So personally I prefer changing the oil at least once a year or every 10k km - for that matter, half the interval distance. So what I do is let the dealer service it, then a year later (roughly half way to the next service) I change the oil and oil filter again.

The MAF sensor controls the air/fuel mixture, so it could be slightly dirty and be affecting the fuel consumption. But honestly, it doesn't seem to be excessive. I would invest in some good MAF cleaner and give the MAF a clean - there are loads of detailed DIY's and youtube vids showing how to do this. Of course, you do have to be careful since the MAF is quite delicate and the wires should not come into contact with anything at all!

There is a very detailed DIY thread here that shows how to get to and clean the Vanos solenoids - BTW, they are the two items plugged in on pic 3 that you posted above.

But now in reality, the N52 does have an inherent throttle response issue, so even with everything running properly, there is always going to be some delay. Takes some getting used to. This is further worsened by the presence of the CDV clutch on the manual gearbox cars, so gear changing can be "hit and miss" at first.

Here's my car after a fair amount of town driving, and then onto some open road driving. I always reset my average consumption when I fill the car. So you can see the sort of driving and of course what my econometer is doing at the same time. Was quite an interesting process doing this vid...

[AdamN52]

For city driving I don't think your fuel consumption sounds too far out of line. I usually get between 10-13L/100km on short trips around town, and will get as good as 7-8L/100km on long hwy trips.

That said, it certainly doesn't hurt to clean up your MAF and VANOS, check your air filter, tire pressure etc.

[lvb125]

I opened the engine cover today.

There is some considerable amount of oil stored just under the valvetronic motor, still in liquid form.

The eccentric shaft sensor plug looks clean, no oil whatsoever in the socket.

Also got the MAF sensor out, looks clean. Still cleaned using MAF cleaner anyway and felt no difference afterward.

I ll post some pictures later.

[lvb125]

Front: (where is the oil on the valve cover leaking from? )


The leak saw on the first picture in OP:


A gasket for Valvetronic Motor leaking?


Under Valvetronic Motor


Between coil 2 & 3


Between coil 4 & 5, aft of valvetronic motor -- seems a lot of oil still in liquid


Eccentric Shaft Sensor Socket: looks clean?


Appreciate any thoughts, what should I prepare to fix. Thanks

[Three_thirty_I]

To me it does seem like the Valvetronic motor gasket is leaking. The oil filler cap gasket is also sweating a lot, so I would start by carefully removing the oil filler cap and gasket, and cleaning thoroughly with soapy water.

The area at the front of the engine above the Vanos solenoids is strange. Well, the "starting point" being on the vertical surface doesn't make sense. I would clean this off carefully, and keep an eye on it to see if it starts leaking again.

I would carefully clean around the eccentric shaft sensor, but the plug itself looks clean to me, which is good. I would also keep an eye on that afterwards.

The valvetronic motor gasket will most likely need to be replaced.

[AdamN52]

Based on those pics I'd say:

• Valvetronic motor gasket is leaking
• Oil fill cap is leaking, had spillage or both
• The VCG is leaking at the front and the air is blowing it upwards as you drive.
• ECC sensor may have a bit of oil in there, but doesn't look too bad to me

Replace those gaskets and clean it all up - you'll be good as new!

[lvb125]

After much procrastination, I am about to take some actions on the oil loss. I reviewed these pictures, and start to think if the oil deposit between coil 4 & 5 (2nd last pic at #13) could be from the spark plug hole. Then the inner VCG is probably leaking badly. I traced the service record and bingo, a VCG leaking was first reported during a service that replaced coils for a misfire back in 2012.

I suppose oil could have gone through the spark plug holes and into the combustion chamber?

Thinking of DIY this whole gasket work, but it frightens me much when ex-mechanic friend chickened out (said VT motor is finicky) and all PITA stories on getting out back side screws and the VC. Really hoping not to break any hose or vents and create a bigger mess! Is it really doable for a newbie?

[Meeni]

It is doable, but not the easiest thing to start you off.

You have a lot of oil around here, I'm actually surprise you loose only a quart per 5k miles with the pictures. When the VCG leaks are fixed, you should see no oil consumption anymore.