BMW N52 6-Cylinder Broken Valve Cover Bolt and ValveTronic Motor Removal – E90, E60, Z4 – 323i, 325i, 330i, 525i, 530i, 2.5si, 3.0si
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.
N52 6-cylinder valve cover bolt set:
N52 Valve cover gasket set:
Click HERE for ValveTronic motor mounting Gasket