[lowrydr310]

I replaced my eccentric shaft sensor in August which required a new valve cover gasket, ESS gasket, and valvetronic motor gasket. All was good for 3000 miles and 5 months but recently I started smelling a faint puff of burning oil from under my hood. Just checked and I can see after parking a while some oil in the rear corner of the valve cover and a drop on the exhaust manifold below.

I did have to use a universal adapter to tighten and torque the bolts along the rear. Maybe I didn't torque them properly? This is an 06 with the magnesium valve cover and flat gasket, and aluminum torque-to-yield bolts.

I haven't taken the plastic engine cover off yet but it looks like some oil may be coming from the center under the valveteonic motor. I recall when replacing this gasket it didn't seem to make a good seal. It's also a different design than the one for the plastic valve covers and doesn't have a lot of rubber on it. If this was leaking, would the oil run along the seam and collect toward the rear of the engine?

UPDATE: Three loose valve cover bolts.

[E92William]

What do you mean by universal adapter? I sure hope it isn't one of these.. your gasket shouldn't be leaking that soon after replacing, either it was a cheap no brand gasket or you didn't torque it properly, I doubt the cover is warped. If the valvetronic motor gasket is leaking it can make a massive mess and make you think it's the valve cover itself. It'll leak and run to the back of the engine since that's the motion of the air entering the engine bay and the way the opposite way the car is accelerating. Try clean up and double check. Also could just retorque with a proper socket and see if any are loose

[3PedalJake]

Think he means a ratchet swivel u-joint, I doubt any readers of this forum even own such a tool as you mentioned.

[E92William]

Originally Posted by 3PedalJake

Think he means a ratchet swivel u-joint, I doubt any readers of this forum even own such a tool as you mentioned.

Oh it makes perfect sense now lol. Well I don't think it being a swivel would have affected torque much as it's still measuring the same.

I used a swivel joint for the bolts in the back of mine too no issue

[lowrydr310]

Yes it was the 1/4" swivel adapter not that goofy socket pictured above.

I replaced the same gaskets on my magnesium valve cover 325 over 2 years ago and they're not leaking at all. I used the same exact brand too, Victor Reinz. All torqued properly following the correct sequence with the torque + angle. I even marked each bolt head after each step to ensure I didn't miss any.

I do recall the valveteonic gasket not seeming to seal properly when doing it on my 330. It's too late tonight but I'll check tomorrow. I suspect the valveteonic gasket since the valve cover gasket is wet directly under it and all the way to the back corner. From there to the front edge it's dry.

Also the weird thing is I didn't notice any of this until recently removing the oil fill cap just to peek inside and check the cleanliness of the valve train. I guess it's possible the oil fill cap gasket is leaking but I don't think it would leak that much so soon, I suspect coincidence.

[3PedalJake]

Originally Posted by lowrydr310

Yes it was the 1/4" swivel adapter not that goofy socket pictured above.

I replaced the same gaskets on my magnesium valve cover 325 over 2 years ago and they're not leaking at all. I used the same exact brand too, Victor Reinz. All torqued properly following the correct sequence with the torque + angle. I even marked each bolt head after each step to ensure I didn't miss any.

I do recall the valveteonic gasket not seeming to seal properly when doing it on my 330. It's too late tonight but I'll check tomorrow. I suspect the valveteonic gasket since the valve cover gasket is wet directly under it and all the way to the back corner. From there to the front edge it's dry.

Also the weird thing is I didn't notice any of this until recently removing the oil fill cap just to peek inside and check the cleanliness of the valve train. I guess it's possible the oil fill cap gasket is leaking but I don't think it would leak that much so soon, I suspect coincidence.

I knew nobody who demands a 6MT would own such a thing, or at least not use it on a valve cover. Mebbe a swingset.

I'm gonna follow this because I still have top engine stuff to do. I did oil pan gasket and all the accessory belt items and OFHG and headers/O2 sensor stuff , but leaving the VCG and intake and vanos and valvetronic stuff till I get it filled back with fluids and brought back to life. At this point I feel like I've taunted the fault code gods enough until I appease them.

I also have a leaky 325i waiting to learn from experience lol.

[lowrydr310]

UPDATE

One of the benefits of work from home is that I can work on my car on my lunch break.

I removed the cosmetic engine cover and inspected, it was perfectly clean around the valvetronic motor. I inspected the valve cover bolts and sure enough the three rearmost bolts on the passenger side of the engine were loose. The rest of the bolts were all tight.

I did this job before on my 325 and it's been leak free for over two years. Not sure what's up with the 330. I know for certain I tightened everything in the proper sequence,7 Nm (63 in-lb) plus 90 degrees, since I marked each bolt head with a small dot of blue marker after initial torque and then a marked a line after the additional 90 degree turn.

Technically these are single use bolts and it's risky to reuse them, but they're cover bolts and not as critical as something like the single aluminum bolt holding the tensioner. So for now I retorqued them to 63in-lb and gave just a slight extra turn, nowhere near the 90 degrees.

[3PedalJake]

Glad you found it. If it was already loose I can't imagine it was ever tight. I think your first hunch is correct, your u-joint bound up or some other malfunction in measuring the torque on those bolts. I've found it's hard to get a good reading with those unless you're careful to support the ratchet head and are actually applying the rotational torque there evenly.

[marvinstockman]

If it still leaks, check the valve cover for micro cracks.

Regarding the 'universal socket', I don't have one, but I've always wanted one!

[lowrydr310]

Originally Posted by 3PedalJake

Glad you found it. If it was already loose I can't imagine it was ever tight. I think your first hunch is correct, your u-joint bound up or some other malfunction in measuring the torque on those bolts. I've found it's hard to get a good reading with those unless you're careful to support the ratchet head and are actually applying the rotational torque there evenly.

I read somewhere that suggested waiting 30 minutes after the initial torque before applying the angular torque. Not sure if that had anything to do with it, I didn't wait, but all other bolts except those three were torqued fine. Now that I think about it I had to use a long extension, and the extension may have been contacting the strut brace or the plastic cowl at the rear causing my wrench to click before the torque was applied to the bolts. It's such a low torque value, it doesn't take much force to click. I'm pretty picky and very precise (bad if I was a paid mechanic, I take too much time) so I'm really not sure how I could have done that, but I guess anything is possible.


I just used a wobble extension this time for the two bolts that weren't as easy to access. I test drove the car with two separate trips yesterday and over 50 miles and the leaks stopped.

Originally Posted by marvinstockman

If it still leaks, check the valve cover for micro cracks.

No more leaks, no cracks. It was loose bolts. Cracks aren't common on the magnesium valve cover N52.

[Jesda]

Glad you found the solution but even known gasket brands, like Reinz and Elring, can fail on initial install. That's happened to me.