[gr8sho]

Originally Posted by oba

I have a 2006 330i sport with mere 26k miles. I noticed the burning smell and a bit smoke out of the hood a couple times after I drove home. When I checked under the hood I saw a drop of oil on a hot metal component outside the lower engine area, and some wet and muddy surface under the valve cover gasket.

I don't think it's urgent to fix. But I quoted from two nearby dealers. They came back to about $1,000 and $1,100 with about 7 hours labor. Car is out of warranty for a year. I think I will have a good inde european car shop do it -- they quoted $300 with 3 hr labor, and good comments about them are out there on the web.

I'm not sure why people aren't more upset with BMW about this issue. I have a very similar situation, Oba, and my 330i is at about 37k. Driving very casually in south florida. The actual leak problem has to do with fatigued aluminum bolts snapping. On my car, the front left bolt is snapped. The local dealership is well aware of the issue and knew exactly where to look. The quotes for the job I've read here are all pretty much book, 7 hours labor, etc. I don't take issue with the dealership, but rather with BMW itself.

To me this is a design issue clearly as BMW designed out the magnesium cover after a brief production run on our cars. It's the magnesium cover that forces use of use once "aluminum bolts". Remember when the N52 was voted the best thing since sliced bread?

My feeling is that if I wanted a leaky valve cover, I'll just stick with an american car. I would rather see BMW step up and take care of this, but if y'all think this opinion is too harsh, I'm sure you'll let me know.

[e90pilot]

I have to agree. I talked a a BMW tech about this and discovered that the issue wasn't so much that the bolts are weak, but they were torques to the incorrect specification. I'm wondering if BMW might have to warrenty the repair since the defect was present at the date of manufacture.

I just had my bolts and gasket replaced yesterday and $1000 to $1200 is normal. But 7 hrs is more than book. Book is 5.5 hrs I think, but I need to confirm that.

Originally Posted by gr8sho

I'm not sure why people aren't more upset with BMW about this issue. I have a very similar situation, Oba, and my 330i is at about 37k. Driving very casually in south florida. The actual leak problem has to do with fatigued aluminum bolts snapping. On my car, the front left bolt is snapped. The local dealership is well aware of the issue and knew exactly where to look. The quotes for the job I've read here are all pretty much book, 7 hours labor, etc. I don't take issue with the dealership, but rather with BMW itself.

To me this is a design issue clearly as BMW designed out the magnesium cover after a brief production run on our cars. It's the magnesium cover that forces use of use once "aluminum bolts". Remember when the N52 was voted the best thing since sliced bread?

My feeling is that if I wanted a leaky valve cover, I'll just stick with an american car. I would rather see BMW step up and take care of this, but if y'all think this opinion is too harsh, I'm sure you'll let me know.

[gr8sho]

Originally Posted by e90pilot

I have to agree. I talked a a BMW tech about this and discovered that the issue wasn't so much that the bolts are weak, but they were torques to the incorrect specification. I'm wondering if BMW might have to warrenty the repair since the defect was present at the date of manufacture.

I just had my bolts and gasket replaced yesterday and $1000 to $1200 is normal. But 7 hrs is more than book. Book is 5.5 hrs I think, but I need to confirm that.

I agree with the quote you were given. I may have misheard the hours, but the quote was a little north of a grand. The picture shows which bolt actually broke. The tech knew exactly where to look for it without removing the engine cover.

[PAKMAN]

like how the 335s have the fuel pump problem and have warranty till 100k we should have this for 100k as well.

[gr8sho]

Originally Posted by PAKMAN

like how the 335s have the fuel pump problem and have warranty till 100k we should have this for 100k as well.

I will likely write to BMW NA once I locate a good mailbox to send it to.

[PAKMAN]

Originally Posted by gr8sho

I will likely write to BMW NA once I locate a good mailbox to send it to.

you think that will work? i will definitely write to bmwNA as well

[shragon]

i agree this seems to be a design flaw and bmw should do something about it.

[PAKMAN]

i've seen people get it within these miles 30xxx-60xxx that is pretty consistent. most people i know have got it after their warranty expired which is pretty BS because of how much it cost to fix the problem.

[gr8sho]

Originally Posted by PAKMAN

i've seen people get it within these miles 30xxx-60xxx that is pretty consistent. most people i know have got it after their warranty expired which is pretty BS because of how much it cost to fix the problem.

My engine is hardly broken in at 37K. I find this all a bit despicable until someone tells me otherwise.

Here's what a $1K repair looks like.

[lux.sh]

is this problem just random or related to driving-style at all?

if aggressive driving could raise the chance of triggering this issue, i better start slowing down..

[e90pilot]

Originally Posted by lux.sh

is this problem just random or related to driving-style at all?

if aggressive driving could raise the chance of triggering this issue, i better start slowing down..

It is not related to aggressive driving. The bolts were not torqued correctly from the factory and will break from normal vibrations from the engine and road. Once you fix it the problem will usually never return. It's not a problem with the bolts themselves but they are fragile.

[gr8sho]

Originally Posted by lux.sh

is this problem just random or related to driving-style at all?

if aggressive driving could raise the chance of triggering this issue, i better start slowing down..

Well, Palm Beach county isn't the kind of place you can really be aggressive. I don't track the car. It is mostly babied by me. But if the mood strikes, I will bounce the rev limiter on occasion.

Part of what I'm hoping this thread will do is encourage N52 owners to look at their cars and either report they've paid for this repair or look in their engine bay and spot the oil leak on the left bank of the engine right under the valve cover. If you spot a oil leak, it shouldn't be hard to locate a broken bolt.

This is a crappy design just because of the fact that BMW decided to change out the magnesium valve cover in place of plastic in later vintage of the engine. I suppose it could also be a quality issue with the bolts themselves, but I suspect that they can't stand up to the resonant frequency the engine transmits and this problem will only resurface again in the future.

To state more around what my personal situation is, I found a local trustworthy repair shop and had them back out the broken stud which shouldn't be hard to do, and replaced just the bad bolt. Hopefully restoring a proper bolt will resolve the leak, but I am suspicious. It will take a few months of regular driving to convince myself either way. I ended up paying for one hour of labor.

To say more about the leak itself, I never lost enough oil to have to add any (remember these engines hold 7 qts of oil), but the fact the leak is there means that your engine bay will get dirty, and I hate dirty for a car I spent this much money on.

[e90pilot]

I talked to a BMW tech about this. He never sees the the bolts that were fixed ever have issue again. Also, the reason BMW changed the design was not really that it was defective (though it might have been), but rather that plastic is way cheaper to mass produce than magnesium.

[gr8sho]

Originally Posted by e90pilot

I talked to a BMW tech about this. He never sees the the bolts that were fixed ever have issue again. Also, the reason BMW changed the design was not really that it was defective (though it might have been), but rather that plastic is way cheaper to mass produce than magnesium.

That premise only works if you give it enough time. I don't think the bolts fail immediately.

So are you saying the tq spec was revised? Do you have the original factory value and the newly published ones?

The one that failed on my engine looks like it could be one of the higher stress points.

I am not a big fan of plastic valve covers. The one in my 3.8L Ford Windstar developed vacuum leaks as the car got older. Despite all the praise that the designers got for that (as was the case with the N52), the long term reliability issues are more important to me.

[Chriztofor]

Has anyone tried to change the bolt(s) without changing the gasket?

[gr8sho]

Originally Posted by Chriztofor

Has anyone tried to change the bolt(s) without changing the gasket?

Yes, that's exactly what I did. Because the bolt is made of aluminum, you have to be careful but for a young engine it shouldn't be too tough to get out.

The question for me now is since some oil got past the gasket, will torquing the cover down actually block the seepage. Time will tell.

[e90pilot]

Originally Posted by Chriztofor

Has anyone tried to change the bolt(s) without changing the gasket?

That's a bad idea. Once the bolt brakes, the gasket becomes saturated in oil and looses its sealing properties. Oil will diffuse through the existing oil in the gasket. If you're going to remove all the bolts anyway, replace the gasket.

[Chriztofor]

Originally Posted by gr8sho

Yes, that's exactly what I did. Because the bolt is made of aluminum, you have to be careful but for a young engine it shouldn't be too tough to get out.

The question for me now is since some oil got past the gasket, will torquing the cover down actually block the seepage. Time will tell.

Originally Posted by e90pilot

That's a bad idea. Once the bolt brakes, the gasket becomes saturated in oil and looses its sealing properties. Oil will diffuse through the existing oil in the gasket. If you're going to remove all the bolts anyway, replace the gasket.

Yes, but GR8 did it and it appears it doesn't leak. If I can spot the broken bolts without having to dismantle everything then I will just change the bolts and report back. If I have to dismantle everything to get to the bolts then I will replace the gasket too.

[gr8sho]

Originally Posted by e90pilot

That's a bad idea. Once the bolt brakes, the gasket becomes saturated in oil and looses its sealing properties. Oil will diffuse through the existing oil in the gasket. If you're going to remove all the bolts anyway, replace the gasket.

I get your point, Marcelo. In this case it was only one bolt. If the leak returns, I will have the whole job done.

Again, I would prefer BMW take care of this issue.

[Chriztofor]

So far I checked the front part of valve cover and I don't see any leaks. I also don't smell any oil burning and I don't see any smoke. This weekend I will get to the bottom of this. I hope the leak is coming from the rear of the valve cover.

[benzo23]

I just ran out and checked on my car, took the plastic cover off and no oil leaks at all around the gasket area and both of those bolts are still intact...ive got 57k on the clock. Guess ill just keep an eye out for this.

[slpymnky]

I think I might have this problem. There is a slight burning smell coming from my car that is only apparent when you get out of the car. I don't have a low oil light on or anything. The smell isn't coming from the engine because I popped the hood and couldn't smell it. I'm still not sure exactly where to look for this. I just look to the left of the engine? How urgent is this? I have an 1100 mile drive coming up in a couple of weeks and am not sure if I need to get this taken care of before.