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BMW N52 6-Cylinder Broken Valve Cover Bolt and ValveTronic Motor Removal – E90, E60, Z4 – 323i, 325i, 330i, 525i, 530i, 2.5si, 3.0si

October 18, 2010

2006 530i, N52 engine
I have two valve cover bolts broken off at the front left corner of the engine. The heads are broken off and I think the body of the bolts are leveled at the engine head (below the valve cover). I think the oil is leaking because of this problem. I am the original owner and the car has 56,000 miles on it. Would you please provide some suggestions and email me instructions on how I should approach this problem?

This answer is applicable to the following N52 engine applications:

*  2006  323i, 325i/xi & 330i/xi
*  2004-2007  525i/xi & 330i/xi with N52 engine
*  Z4 2.5 and 3.0 through 2006 with N52 engine

The early N52 engine uses aluminum valve cover bolts (and a Magnesium valve cover).  These bolts have a known history of breaking.  If the bolts are broken off even with the cylinder head surface (in other words, you could not grasp them with vise-grips after removing the valve cover), you will have to drill them and then use a screw extractor (easy-out, etc.) One purpose made product that works well is called Drill-Out (from Alden tools). This tool both drills and removes the broken screw/bolt/stud.

Note that BMW specifically states that the bolts are intended for a one-time use. In other words, they should be replaced if/when they are ever removed. The bolts are sold as a complete set.  And, of course, you’ll need a new valve cover gasket set.

Additionally, if the valve cover is being removed, the ValveTronic motor must be removed as the first step.  The Bentley repair manual details the proper procedure for removing and aligning and reinstalling the motor.  The motor should be installed with a new gasket and (according to the Bentley repair manual) new bolts, as with the valve cover.

Bentley repair manuals:

N52 6-cylinder valve cover bolt set:

N52 Valve cover gasket set:

Click HERE for ValveTronic motor mounting Gasket

Click HERE for ValveTronic motor mounting bolts

  1. Daniel permalink

    Hi Mr. Otto,

    Thank you for the quick reply and all the prompt deliveries of my purchases. I hope to be able to replace my valve cover gaskets and bolts with your help!

    According to the Bentley Service Manual I bought from your website, it looks like I have to disengage the valvetronic motor before I can remove the cylinder head cover(is that true?). I also did read the instructions on how to remove the valvetronic motor and it seems too easy to believe. However, I am very concerned about messing up the timing of the valvetronic motor and the car engine if I do it wrong. Would you please tell me if it is possible for to mess up the timing of my engine or anything related if I remove and reintall the valvetronic incorrectly? Any suggestions and warnings are greatly appreciated!

    Have a great day! :-)

    • Yes, the ValveTronic motor does indeed need to be removed in order to remove the valve cover. The Bentley repair manual covers this on pages 130-17 and 130-18. It appears to be very straight forward. Just follow the steps shown.

  2. Philip permalink

    Hey Mr. Otto,

    When removing the ValveTronic motor, do I need to us new bolts and a new gasket?

    • BMW does not mention that the ValveTronic motor mounting bolts should be replaced. However, the Bentley repair manual notes that they should not be reused. At this point, we would suggest that you replace the bolts, per the Bentley manual. Of course, it would be a good idea to install a fresh gasket when the motor is removed and re-installed, as well.

      Click HERE for ValveTronic motor gasket

  3. Denice permalink

    Ok, I am a bit on a loop here. This is making it sound like the valvetronic motor has it’s own gasket. Is this true? Or did I mis-read info? Can anyone tell me how to remove the valvetronic motor being that it is easy? Just don’t want to mess anything up. Also what tool to use. I am trying to remove it with a 6mm socket to no avail. Thanks!

    • Yes, the ValveTronic motor does mount with a gasket.

      The motor is not difficult to remove or install, but there is a specific procedure to follow. The procedure is outlined in the Bentley manual (noted above). We would suggest that you do not attempt removal without the full two-page detailed write-up in the manual.

  4. Is it possible for oil to leak from the valvetronic motor gasket? I have had a smoke smell coming from the engine, so I suspected a faulty valve cover gasket. However, I instead found oil pooled in the wells housing the ingnition coils on the left and right side of the valvetronic motor.

    • Yes, oil can certainly leak from the motor’s mounting gasket. Did you see evidence of the oil leakage originating at the gasket and then running down into the plug wells? If not, it may just be coincidental that the cylinders on either side of the motor are leaking at the valve cover/ spark plug well gaskets. In this case, you would pull the valve cover and replace all of the valve cover gaskets (as well as installing a new Valvetronic motor gasket).

  5. Thanks for the info! I couldn’t get a good look at the bottom of the gasket to check for signs of oil leakage(since the motor and connectors are in the way). I’ll have to remove the motor to know for sure (and replace the gasket in any case). Hopefully it’s not the internal valve cover gaskets.

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