[3PedalJake]

I have a early production 325i with the stereotypical broken aluminum timing cover bolts (BMW calls the head bolts) under the vanos gears. I have the VC off now doing VCG I half expected to find this since the external bolt behind the OFH was broken when I bought it. I know theres a lot of threads about this but I can't find any DIYs on it. I don't mind buying the cam/crank locking tool theyre @$100 on fleabay but I don't know what the procedure is and I'm not clear on the instructions in the Bentley manual for timing chain, and if I need to follow all of that just to get at the bolts.

The car has almost 200k miles on it it's probably been like that for a very long time. It looks like it weeps a very small amount of oil there down onto the AC compressor in the front corner but not enough to drip onto the ground. I'm considering just sealing it back up with new VCG and putting this on hold until I'm equipped and prepared to tackle it, but if someone can point me towards a good DIY I'd be much obliged.

[e90yyc]

What's your build date? I'll see if I can find the procedure.

This doesn't answer any of your questions, but were there any symptoms associated with these broken bolts?

I have a tinny rattling sound (like marbles in a can almost) that happens once the car is warm, and can be "silenced" for a period of time by blipping the throttle at idle. Specifics are slipping my mind, but I recall it being something oil related.

Not trying to threadjack you here—just thought I'd ask if there are any symptoms.

[smass]

Below is a link to my low budget fix for the issue
https://www.bimmerfest.com/threads/n...-guide.958844/

[3PedalJake]

Originally Posted by e90yyc

What's your build date? I'll see if I can find the procedure.

This doesn't answer any of your questions, but were there any symptoms associated with these broken bolts?

I have a tinny rattling sound (like marbles in a can almost) that happens once the car is warm, and can be "silenced" for a period of time by blipping the throttle at idle. Specifics are slipping my mind, but I recall it being something oil related.

Not trying to threadjack you here—just thought I'd ask if there are any symptoms.

It is 06-2005, the procedure should be the same for all N52s, it's just the early productions that have this issue tho. No symptoms except the slight weep in the front right corner, the engine runs great other than that. The VC was leaking at the rear pretty heavily, I pulled 5 broken bolts out of that so no wonder. It has 196000 on it and I'm betting it's been like this most of it's life because all the threads I've found on it suggests it fails relatively early in life if it's gonna fail.

No issues with threadjacking, sometimes the solution you're looking for is at the bottom of an entirely different rabbit hole, happy for any kind of input.

[3PedalJake]

Originally Posted by smass

Below is a link to my low budget fix for the issue
https://www.bimmerfest.com/threads/n...-guide.958844/

This is pretty much just what I'm looking for, I'm still in the figuring out if it's something I'm capable of tackling stage, this looks promising. I'm gonna read over this until I understand it, then prolly back with some Qs if you don't mind. Thanks!

[3PedalJake]

smass that's a great writeup, thanks! It's pushing the boundaries of my skillset but looks like I might be able to do it. I ordered the cam/crank locking tool kit and I'm probing around underneath. I found the crank locking pin plug, but can't figure out how to get it out. I managed to get a small screwdriver through the ring on it's nose but unable to budge it. How did you pull this out? And is it really necessary to lock the crank if I'm not tinkering with the crank hub? It will be in TDC position when I get the cams lined up to where the locking bracket will slip on, correct? Is it possible that it would move even with the car in gear and parking brake on? Is there any part of the up-top procedure that has the potential to move it with the cams locked down?

Also, how difficult is it to remove and reinstall the gears, do they just slide off and on?

Thanks for any input, much appreciated.

[smass]

The plug is just plastic. Mine did not give issue being removed. The crank could move just from valve spring pressure so you are going to want to lock it. The gears just slide off once the bolts are removed.

[3PedalJake]

Originally Posted by smass

The plug is just plastic. Mine did not give issue being removed. The crank could move just from valve spring pressure so you are going to want to lock it. The gears just slide off once the bolts are removed.

Thx, what method did you use to pull it out? By the nose ring or prying at the block under the tab, I've tried both but it's not moving. I may just not be applying enough force, I'm leery about the plastic but maybe just need to pull harder.

[Mantraxalos]

This boy pulls apart an N52B25 for rebuild. Maybe you can get some useful info from watching it.

https://www.youtube.com/watch?v=5-Dx...83Yppw&index=4

[3PedalJake]

Originally Posted by Mantraxalos

This boy pulls apart an N52B25 for rebuild. Maybe you can get some useful info from watching it.

https://www.youtube.com/watch?v=5-Dx...83Yppw&index=4

Thanks, anything that shows top end work and timing procedures is useful.

[3PedalJake]

I got the TDC hole plug removed using a pin punch through the nose ring of the plug and levering against the protruding ledge around it. This is a job all done by feel because there is no way to see this plug either from bottom or top unless you remove the intake manifold. Now to wait on the timing tool set. I feel like I'm flying high above my skill set with this job, I'll be glad when it's done and I can get back in my wheelhouse to suspension/drivetrain work.

[e90yyc]

Nice work

[3PedalJake]

Originally Posted by e90yyc

Nice work

Thx pal. I'm hoping this job goes better than the input shaft seal (still untested BTW, car hasn't come off the lift yet). The tool kit arrived this afternoon and I picked up Vanos actuator bolts at BMW stealer. Ironically the aluminum "head" bolts were the first parts I bought for this car when I bought it last year, changed the external one under the manifold and the other 3 have been waiting since. Hopefully I'm not gonna cause any new problems I didn't have yet, but you know how that goes.

[lowrydr310]

I have a 6/06 build 325i and all the bolts are intact. I don't know if they're original or if the rpevious owner had them replaced at some point but there are 258k on the car now and they're still intact.

I later acquired a 12/05 build 330i and during my inspection I noticed the external bolt head snapped off. When I opened the valve cover to replace the eccentric shaft sensor, the two bolts directly under the cams also have the heads snapped off. So I replaced the external bolt with a new one (loosening the intake manifold for access) but left the ones under the cams alone. There are zero oil leaks so I'm leaving it alone, though I have the bolts needed since I bought the set.

[3PedalJake]

Originally Posted by lowrydr310

I have a 6/06 build 325i and all the bolts are intact. I don't know if they're original or if the rpevious owner had them replaced at some point but there are 258k on the car now and they're still intact.

I later acquired a 12/05 build 330i and during my inspection I noticed the external bolt head snapped off. When I opened the valve cover to replace the eccentric shaft sensor, the two bolts directly under the cams also have the heads snapped off. So I replaced the external bolt with a new one (loosening the intake manifold for access) but left the ones under the cams alone. There are zero oil leaks so I'm leaving it alone, though I have the bolts needed since I bought the set.

Mine are opposite, my 03/05 production 330i has all bolts intact. Likewise I'm not sure if they were ever replaced, but I got the impression that I was the first one to pop the VC off. The 325 has the same broken as your 330, the external and 2 of the 3 inside. I just found one of the heads lodged between the timing chain guide and block about halfway down, that's gonna be like the old "Operation" game trying to get it out with long long longnose pliers after I get the vanos gears off.
I was gonna just seal it back up, it is leaking out the front but not profusely, but smass post got me thinking I could fix it, so I knew it would just gnaw at me until I tore it apart again so giving it a shot.

[lowrydr310]

Originally Posted by 3PedalJake

I just found one of the heads lodged between the timing chain guide and block about halfway down, that's gonna be like the old "Operation" game trying to get it out with long long longnose pliers after I get the vanos gears off.

I didn't find the bolt heads, however my 330i had the oil pan gasket replaced shortly before I bought it, along with many other common 100K+ mile E90 failure items including the valve cover gasket, engine mounts, water pump, radiator, thermostat, all coolant hoses, and even the starter.

That makes me suspect the former owner found out about broken bolt heads in the oil pan and wanted to sell the car out of fear, despite sinking a bunch of money into recent maintenance.

[3PedalJake]

I almost can't believe I did this and it worked. A couple days ago I was ready to slap the VC back on and pretend I never saw them.

Turns out all 3 underneath the VC were broken, one just had the head still sitting on it. One was missing and the 3rd was lodged between the chain guide and block, I did manage to extract that with longnose pliers. The 2 front bolts wouldn't budge with the usual dental picks or sharpened flatblade, I had to drill them out with right angle drill and use a bolt extractor on them, happily they complied with that. The one under the chain guide luckily spun right out, because that is too far down to get a drill in there. The rest went exactly as described in smass DIY, I wouldn't have even attempted it if he hadn't posted that, thanks a million bro!

[Mike K]

Great job man!

[Biginboca]

Great work 3PedalJake !!

[smass]

Awesome job! Never seen all 4 broken before. I thought I was unlucky with 2. Enjoy your N52. It is worth keeping it in good shape. I spent the last week changing turbo oil lines and a valve cover gasket on my pain in the ass diesel!

[3PedalJake]

T/Y gen'lminz

Got it all buttoned up and out for a test ride, just a brief moment of terror at first when it shook and bucked and threw a CEL, but that was just me not getting #6 coil plugged together tight, had a misfire. Corrected that and it's running fine. Time will tell if it fixed the oil weeping, but with all 4 bolts missing I'm sure it will be better than it was. Thx again for the tips!