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BMW 3-Series (E90 E92) Forum
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snapped valve cover bolt
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07-07-2016, 01:45 AM | #1 |
e92 Driver
8
Rep 56
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snapped valve cover bolt
so my electric water pump recently failed with the typical hairline crack on the plastic housing and since I was going to have to drain the coolant I decided to replace the oil cooler gaskets as well as the valve cover gaskets as they were all leaking.
as I was wrapping up the valve cover installation, I was torquing all the bolts to the recommended 7lbs and one of them snapped. I've read some threads on this forum as well as others stating the best way to fix it is to drill it out, but I was curious if anyone's ever had this happen to them and how much of a pain was it to fix. I'm kinda not sure I want to do it myself because I certainly do not want to make the problem worse, but if anyone has any tips or has had this happen please help!
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2008 335i cp Montego Blue
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07-07-2016, 06:12 AM | #2 |
General
19156
Rep 19,708
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Well at least it is one that you have easy access to and the screw is aluminum, so it is easy to drill. I'm not sure about the N54/55 cylinderhead, but on the N52 that screw position is a thru-hole, meaning you may be able to just thread the broken screw all the way through the hole. On my N52 (I just did the valve cover over the weekend and had to chase the treads ay this screw position) the screw shaft protruded through the head, so maybe you can grab the bottom end of the screw and turn it out.
If not, you should be able to use an Easy Out to back the screw out. The trick here is you need to buy the correct sized Easy Out and a machine shop tool called a Center Punch, which is a tool used to dimple metal to prevent a drill bit* from "walking" away from the spot you intend to drill the hole. You need to center-punch the screw shaft then drill it. Use a small diameter Easy Out and the correct-size drill bit for the screw size you are removing. The screw is a 7MM shaft-size. The smaller the size of the drill bit the slower speed you need to drill the hole, so use a variable-speed drill on slow speed. If the hole is a thru-hole, the drill bit may grab the screw shaft and run it through the hole, so be careful (but you're problem will be solved...). If any of this seems too daunting for you, I recommend taking the car to an automotive machine shop and have the screw removed for a reasonable fee. You don't want to mis-drill the screw and chew up the threads in the hole of the cylinderhead. If that is not viable, then you'll probably need to remove the valve cover and grab whatever is remaining of the screw shaft with Vice Grips and remove it. *Just so I don't get any shit from the machinists out there, "drill bits" are actually called "drills". The electric tools we normally call "Drills" are really called "Drill Motors". Good luck with it.
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A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
Last edited by Efthreeoh; 07-07-2016 at 06:17 AM.. |
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07-14-2016, 02:05 PM | #3 |
Private
10
Rep 71
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Drives: 2007 n54 335i and 2006 n52 325
Join Date: Jul 2016
Location: Maui HI
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I had a similar problem
What a pain in the ass. On my n52 my coolant inlet bolts snapped in the engine block while driving had to almost pull the motor to extract the bolts ?
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