2012 E91 318D N47 Oil leakage at the rocker cover; guidance required.

[SkippyTom]

Greetings to everybody.

My 2012 E91 318D, with 157,000 miles and an N47-D20C engine, has developed an oil leak. I discovered it a few days ago while conducting tests with ISTA+ on the exhaust sensors. Upon placing my hand at the rear of the engine, I detected oil. I recorded a video to inspect the area, as access was restricted, and observed the oil leak. However, I could not ascertain the precise source; the oil was located at the rear, on the driver's side, and slightly at the top of the rocker cover on the driver's side.

Thoroughly cleaned the region, finding no oil around the injectors. There is no noticeable leakage around the rocker cover gasket, however there seems to be sealant that is shimmering and somewhat moist. After running the engine, I inspected the rocker gasket area for oil seepage, but saw no obvious signs.

The rocker cover does not seem to be fractured or cracked; nevertheless, I will examine it and the gasket region more thoroughly when I drive the vehicle to work on Wednesday, since I need to get a liter of oil just in case.

I purchased the automobile in February 2024, and the seller just replaced the chain and installed a new clutch due to the prior chain's loudness. It seems he may have used the previous rocker gasket or even changed it; nevertheless, it seems gasket sealant has also been applied, resulting in the visible rubbery material between the head and rocker cover. I will ascertain information from the vendor, since I remain in contact with him.

I suspect the rocker cover is the issue, since it seems to be a prevalent problem with the N47; I will post my results in a few days.

The oil level was somewhat low when I first identified the problem, prompting me to add a quarter of a liter that I had remaining. Upon checking it today, two days later, it seems low once again. I assessed the level while cold, hot, and after a three-minute cooldown, and it looks to be barely over the minimal threshold.

I will assess the situation in a few days when I use the automobile for a 100-mile round trip to work and will report my observations.

The only additional point I should note is that the engine was very hot on the day I identified the leak, which may be attributable to low oil levels, although I am certain I replenished it three weeks before.

It is conceivable that it may also be...

The valve cover may be damaged due to heat and may be deformed.

Fracture located in the valve cover.

The previous gasket may have been reused following the timing chain replacement, and gasket sealant was subsequently applied.

I am currently optimistic that it only requires a new gasket; if that is the case, would it be prudent to additionally apply a gasket sealant?

Any other recommendations on leak detection and guidance on gasket replacement procedures? I anticipate that the injectors will not be very difficult to extract, given they were presumably installed in January of this year when the chain was rebuilt.

Are there any further factors to explore about the source of the leak, and any advice would be highly appreciated?

I will provide an update after I identify the source of the leak, and because the vehicle has completed 8,000 miles, I will do an oil change immediately after rectifying the issue.

Finally, I will detach the turbo pipe to inspect for oil leaks and assess the impeller for any play.

Once again, any assistance would be much appreciated.

[DSM10000]

I suspect they used an old gasket with sealant. They get brittle during heat cycles and should constantly be changed; I never reuse them.
I do not use sealer, since the rubber gasket is sufficient and BMW does not recommend its usage.
Remember to acquire four new injector seals while replacing the gasket and ensure that the injectors are reinserted into their original cylinders.

[SkippyTom]

Indeed, I will also replace the injector gaskets and tighten them to 10 Nm in a spiral pattern without using sealant. I had been seeking a lower setting torque wrench for some time, making this an opportune moment to get one.

I will first report my findings to ensure I am proceeding correctly and then inquire with the seller about the usage of an old gasket. He is a reasonable person, and I am certain he will provide an honest response. As I said, it seems like gasket sealant has been applied, so I am hopeful that the issue is limited to that and not anything more severe.

I believe I can handle it independently and will verify if I require additional components, such as new copper washers for the injectors or possibly stretch bolts for the injector hold-downs. With all due respect to the seller, he provided the vehicle at a very reasonable price, considering the work he performed; however, he may have taken a few shortcuts where he genuinely believed he could. Nonetheless, this situation is advantageous, as I can communicate with him regarding other items he should consider replacing when addressing vehicles with chain issues, as he engages in this work on the side.

Thank you once again, my buddy

I need guidance on a new shock configuration and a DDE ECU software upgrade; I will initiate separate discussions for these topics as necessary.

[SkippyTom]

A concise update: I undertook a quick drive of roughly 7-8 miles today. Upon returning, I examined the vehicle and saw a noticeable leak, which seems to originate from the upper section of the valve cover rather than the gasket at its junction with the cylinder head.

The area around the oil filler neck has a slightly elevated part that seems to connect to the main valve cover. This gap was moist, as was the rear upper driver's side (UK) of the valve cover, indicating a significant leak.

Inspected the oil level, which was below the midpoint on the dipstick, and subsequently purchased one liter to elevate it to a level between halfway and full.

I am now ambivalent about whether to use the automobile for a 100-mile business journey tomorrow.

I like the leak to be as transparent as possible; but, this may jeopardize the vehicle. My friend has volunteered to drive, so I will see him in the morning to examine the car and proceed accordingly.

The current assessment indicates that a full replacement of the valve cover is necessary, which is not ideal; nonetheless, if this is the situation, it must be accepted.

Is it advisable to purchase the original BMW part for £400, despite my financial constraints, or should I consider more cheaper alternatives, such as Febi, which are priced between £100 and £200? I assume the least expensive choices are not authentic. Any advise and recommendations would be appreciated.

I generally prefer authentic BMW parts; however, the cost of £400 is currently prohibitive for me. Additionally, I must consider the expense of genuine BMW valve cover gaskets and copper washers for the injectors. Would a used valve cover from an identical specification and model year engine be compatible?

Is there any potential source for the leak above the valve cover? A prevalent vulnerability that I need to examine?

I will examine the automobile again tomorrow after work to thoroughly assess the leak and anticipate obtaining my answers.

I have included an image indicating a green arrow directed toward the seam exhibiting a little oil presence, and a red circle highlighting the location of the main leak. I will attempt to send images showing the precise leak so far.

[keithmerc220]

Oil will inevitably escape from any containment and will fluctuate in value both upward and downward.

Utilizing sealant is acceptable, provided the appropriate kind is used for the task.

I use Stagg Wellseal for rubber or grooves on metal. Minimal quantity required, innocuous in oil, non-hardening, regrettably expensive.

[Craigbelont]

I would think over about the whole situation