[Fritzer]

Originally Posted by HawkeyeGeoff

Have you ever seen what a Midwest car goes through? Spray away homie.

Right down the side of the block past the crankcase? I feel like excess water isn't supposed to be down there and may not drain properly. Also to do that I would have to spray right on top of the intake manifold, lots of wires, sensors, radiator hoses. I'm definitely paranoid of doing something like that. I would reckon you're right and it's fine but it is still a worrisome thought if I fuck something up.

[Fritzer]

Originally Posted by CTinline-six

Since those bolts are aluminum, they shouldn't be in that tight. I've heard of people spinning out broken valve cover bolts by hand or with a vice-grip.

I'd try to find a reverse rotation drill bit and see if you can slowly spin it out then just screw in the new bolt.

That's not a bad idea. The most popular way to extract seems to be with a pick. Although considering it's aluminum, I could probably use one of those hand twist plugs and screw down into the bolt as well.

[Efthreeoh]

Originally Posted by Fritzer

Everything is more expensive in California. Although maybe he is charging me too much, can anyone chime in?

Yeah I was honestly thinking about doing it myself, also I could clean out the side of the engine from all the oil and sludge built up. I honestly don't think anyone has ever cleaned down there. Too paranoid too just spray because of all the hoses.

All you need is a bolt extractor. But this is a head bolt, not a simple aluminum valve cover bolt. Head bolts are heat treated hardened aluminum bolts, so it will not drill as easy as you think. Head bolts are usually fine-pitch thread and a high-thread class, which means there are more frictional forces on the threads because there is more surface area between the threads and the class of fit between the threads is a tighter tolerance, so it is probably not going to spin out as easy as you think. If you drill off center, it will make it worse, or even damage the cylinder head. Then you need a good torque wrench and degree index to set the correct torque on the new bolt.

If you do not have a lot of experience extracting bolts from recessed holes and have the proper tools, then the shop price is worth it IMO. The LAST thing you want to do is fuck up the head casting.

[Fritzer]

Originally Posted by Efthreeoh

All you need is a bolt extractor. But this is a head bolt, not a simple aluminum valve cover bolt. Head bolts are heat treated hardened aluminum bolts, so it will not drill as easy as you think. Head bolts are usually fine-pitch thread and a high-thread class, which means there are more frictional forces on the threads because there is more surface area between the threads and the class of fit between the threads is a tighter tolerance, so it is probably not going to spin out as easy as you think. If you drill off center, it will make it worse, or even damage the cylinder head. Then you need a good torque wrench and degree index to set the correct torque on the new bolt.

If you do not have a lot of experience extracting bolts from recessed holes and have the proper tools, then the shop price is worth it IMO. The LAST thing you want to do is fuck up the head casting.

This is what I was thinking. Like I said previously I'm probably going to take it to the aforementioned shop this evening, or definitely on the weekend if they're open. $100 is a good chunk of money for something seemingly so small, but it seems worth it. The tech seems like a nice guy, spent a decent amount of time on the phone with me educating and talking about technical details regarding head bolts and other issues, really helpful. Hopefully he'll let me shadow him and see how he does it so I can learn some more.

Thanks again Ef, you rock!

[Denny347]

Originally Posted by Efthreeoh

The OFH bolts are not one-time-use aluminum. They are steel and can be reused. The cylinder head is aluminum and the OFH is aluminum. Steel does not react with aluminum as it does with magnesium, which is why the OFH bolts are steel. BMW uses aluminum bolts for items that bolt to the magnesium engine block, because steel bolts will have a galvanic reaction with the magnesium. The '06 N52 uses aluminum bolts for attaching the magnesium valve cover to the aluminum cylinderhead because the valve cover is magnesium. The later N52 with the plastic valve cover uses steel bolts to attach the valve cover to the aluminum cylinder head.

The OP's engine has a broken head bolt, which the N52 is well known to have a problem with. The fractured head bolt has nothing to do with the OFHG repair and is just coincidental that he noticed it post replacement of the OFHG. The repair is quite easy and just requires extraction of the bolt shaft and replacement. There are two head bolts under the valve cover at the front of the head at the timing case that also can break in a similar fashion.

Exactly. Mine broke they very same way. Took it in and come to find out, both bolts under the valve cover were also broken.

[Fritzer]

Update: Local indy fixed my one external bolt. They also included the three remaining bolts as they come as a kit. Cost $118 out the door. Didn't get a chance to watch them because of work/time restraints - oh well. Seems relatively simple once you get the hang of it anyway.

Just had my VCG replaced about 5,000 miles ago and they didn't mention the interior cylinder head bolts so I think I am fine for the time being. Wish I knew about this then though, would have asked them to replace those as well for peace of mind.

I don't know if I can mention the shop or not on here, but shout out to B and B Autohaus in San Diego! The guys there are very knowledgeable and know what's up, they specialize in BMW as well. First time there are very pleased compared to service at other Indy shops around me.

[Efthreeoh]

Glad to hear it worked out for you. $118 was a good price IMO and well worth letting a professional handle it.

[Qor246]

Hi. Can anyone help me major oil leak? I have a 2011 BMW 328i sedan.

BMW said I had two oil leaks. One from oil pan gasket and other from oil filter housing gasket. They replaced both, However, major oil leak didn’t go away. I’m losing about a quart of oil per day. After replacing OFH, Dealer said leak is coming from behind the oil filter housing, from front head bolts. They are aluminum bolts and either stretched or cracked. Dealer said to fix issue they would have to remove valve cover to get to the head bolts under the intake and remove vano gears to get to replace these bolts. They are quoting $2000 for repair. Can anyone provide guidance? Dealer replaced valve cover gasket last year and wondering whether they removed these head bolts during repair? In which case, would sulev cover their workmanship? I’m not very technical and would appreciate any help.

[feuer]

Originally Posted by Qor246

Hi. Can anyone help me major oil leak? I have a 2011 BMW 328i sedan.

BMW said I had two oil leaks. One from oil pan gasket and other from oil filter housing gasket. They replaced both, However, major oil leak didn’t go away. I’m losing about a quart of oil per day. After replacing OFH, Dealer said leak is coming from behind the oil filter housing, from front head bolts. They are aluminum bolts and either stretched or cracked. Dealer said to fix issue they would have to remove valve cover to get to the head bolts under the intake and remove vano gears to get to replace these bolts. They are quoting $2000 for repair. Can anyone provide guidance? Dealer replaced valve cover gasket last year and wondering whether they removed these head bolts during repair? In which case, would sulev cover their workmanship? I’m not very technical and would appreciate any help.

No reason to touch those bolts when working on VCG or OFHG. Either DIY or find good independent shop.

[Fritzer]

Originally Posted by Qor246

Hi. Can anyone help me major oil leak? I have a 2011 BMW 328i sedan.

BMW said I had two oil leaks. One from oil pan gasket and other from oil filter housing gasket. They replaced both, However, major oil leak didn’t go away. I’m losing about a quart of oil per day. After replacing OFH, Dealer said leak is coming from behind the oil filter housing, from front head bolts. They are aluminum bolts and either stretched or cracked. Dealer said to fix issue they would have to remove valve cover to get to the head bolts under the intake and remove vano gears to get to replace these bolts. They are quoting $2000 for repair. Can anyone provide guidance? Dealer replaced valve cover gasket last year and wondering whether they removed these head bolts during repair? In which case, would sulev cover their workmanship? I’m not very technical and would appreciate any help.

The head bolts would not have been touched during the VCG replacement. From what I understand, the head bolts shearing is not covered by the SULEV warranty, it should be covered by standard warranty or an extended, however. Did they replace your OFHG and OPG under any warranty? I would recommend finding an well known and well reviewed independent shop specializing in BMWs to replace the head bolts.

If you don't mind me asking, how many miles are on your car?

[Qor246]

127000 miles.

[Fritzer]

Originally Posted by Qor246

127000 miles.

o_o

tfw 133k and already had one visible sheared bolt

[Meeni]

Originally Posted by Pladi

I would def go back. Be firm and professional. Its very hard to believe that bolts shear by themselves unless you stress them and weaken.

This particular bolt is notorious for being overtorqued from the factory and very often sheers itself off.

[wsybert]

Originally Posted by Fritzer

...Just had my VCG replaced about 5,000 miles ago and they didn't mention the interior cylinder head bolts so I think I am fine for the time being. Wish I knew about this then though, would have asked them to replace those as well for peace of mind. ...

The bolts under the cover are not easily seen, unless you are looking for them. Even then, one in back impossible to see. Most would miss these unless looking for them. If it still leaks slightly, then it’s very likely they are broken as well. I just replaced mine and you will have to remove the cam sprockets to get to the front two and the chain and guides to get to the last one. Not for the basic DIYer.
I replaced the one you replaced first. Then did the pan gasket and found the three bolt heads from the ones under the cover. Then did those.
So I have new OFHG, Oil pan gasket, VCG and bolts. All dry now!!

Mine is a 2006 330i 107k

[smass]

Originally Posted by Efthreeoh

All you need is a bolt extractor. But this is a head bolt, not a simple aluminum valve cover bolt. Head bolts are heat treated hardened aluminum bolts, so it will not drill as easy as you think. Head bolts are usually fine-pitch thread and a high-thread class, which means there are more frictional forces on the threads because there is more surface area between the threads and the class of fit between the threads is a tighter tolerance, so it is probably not going to spin out as easy as you think. If you drill off center, it will make it worse, or even damage the cylinder head. Then you need a good torque wrench and degree index to set the correct torque on the new bolt.

While the broken bolt is called a head bolt, it does not hold pressure on the main part of the head gasket. The broken part is just a normal aluminum bolt and spins out by hand once you can get a pick on it. The leaking oil is traveling up the threads which keeps it from getting stuck.

To change it, remove air box, loosen intake manifold bolts and pull back front of intake an inch or so.

[Efthreeoh]

Originally Posted by smassey321

While the broken bolt is called a head bolt, it does not hold pressure on the main part of the head gasket. The broken part is just a normal aluminum bolt and spins out by hand once you can get a pick on it. The leaking oil is traveling up the threads which keeps it from getting stuck.

To change it, remove air box, loosen intake manifold bolts and pull back front of intake an inch or so.

If there is oil in the threads, it will never torque properly.

[smass]

Originally Posted by Efthreeoh

If there is oil in the threads, it will never torque properly.

Agreed but that is how the oil ends up on the top side of the head. When mine was broken, I would see oil pooling around the leftover bolt shaft. When I turned the engine off, it would slowly drain back down. The oil is coming from the loose gasket a few inched down the shaft. Once it is clamped properly, oil no longer gets in there. I have changed a couple now and they are still leak free.