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BMW Cylinder Head Bolt Testing
 
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Pelican Technical Article:

BMW Cylinder Head Bolt Testing

Nick Czerula

Time:

3 hours3 hrs

Tab:

5

Tools:

Socket set, E10, E12 sockets

Applicable Models:

BMW 325i Sedan (2006)
BMW 325xi Sedan/Wagon (2006)
BMW 328i Coupe/Conv (2007-13)
BMW 328i xDrive Coupe (2009-13)
BMW 328i xDrive Sedan (2009-11)
BMW 328i xDrive Wagon (2009-12)
BMW 328i/xi Sedan (2007-11)
BMW 328i/xi Wagon (2007-12)
BMW 328xi Coupe (2007-13)
BMW 330i/xi Sedan (2006)
BMW 335d/i/xi Sedan (2007-11)
BMW 335i xDrive Coupe (2009-13)
BMW 335i xDrive Sedan (2009-11)
BMW 335i/is Coupe/Conv (2007-13)
BMW 335xi Coupe (2007-13)

Parts Required:

Head bolts, valve cover gasket

Hot Tip:

Check for oil leaks down left side of engine

Performance Gain:

Repair broken head bolts

Complementary Modification:

Replace valve cover gasket

BMW E90 models have had a few problems with head bolts breaking. The external head bolts can break, sometimes causing an oil leak, sometimes not. If you have oil leak down the left side of your engine, check that this bolt is intact before condemning other parts. Repairing these head bolts can be done in a day by an experienced person.

When the internal head bolts fail, it can be a much bigger deal. The internal head bolts can cause engine overheating and internal cooling system leaks. Repairing these head bolts are quite challenging and may be better left to a professional. Camshaft removal is required and this is a daunting task.

In this tech article, I will go over how to inspect the cylinder head bolts to check if they are broken.

Remove engine covers. See our tech article on engine cover removing.

The head bolt I see broken most often, is the one right behind the oil filter housing (green arrow).
Figure 1

The head bolt I see broken most often, is the one right behind the oil filter housing (green arrow). The oil filter housing is shown removed in this photo to give you a good view of the bolt. When this bolt breaks there isn't always an oil leak associated with it. I would suggest inspecting each time you replace your engine oil. To replace this bolt, you will have to move the intake manifold out of the way to, see our tech article on intake manifold replacing. Then, what is left of the bolt will just spin out. I haven't had any that were stuck and would not come out by hand. Use a pick to rotate bolt until it is out enough to remove by hand. Install and torque new bolt and reassemble engine.

If you find the external head bolt is broken, I suggest removing the valve cover (see our tech article on valve cover replacing) and inspecting the remaining head bolts.
Figure 2

If you find the external head bolt is broken, I suggest removing the valve cover (see our tech article on valve cover replacing) and inspecting the remaining head bolts. This can either give you piece of mind or inform you of a needed major repair. The green arrow in this photo points to where a head bolt should be, it is broken and the head is missing. The yellow arrow points to the intake camshaft actuator for a point of a reference. When this head bolt is found broken, the repair procedure difficulty increases to the professional level. The camshaft has to be removed and multiple special tools are required to do this. Some of which are, camshaft timing tools, camshaft journal alignment tool. If you find this bolt broken and there are no other symptoms, have the bolt replaced as soon as possible. This head bolt can also be associated with engine overheating and internal cooling system leaks. Keep this in mind when dealing with these issues.

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Comments and Suggestions:
AyeJay Comments: I have a snapped bolt where the same location on the pic you provided, do I buy the 4 piece aluminum set ? Thanks.
October 11, 2016
  Followup from the Pelican Staff: Yes, I would replace the set. Give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
Steve Comments: If all the internal bolts are broken can it lead to engine seizing? Will the bolt heads damage the engine?
August 28, 2016
  Followup from the Pelican Staff: Yes the engine can fail and the engine would be damaged if the bolts are loose. - Nick at Pelican Parts  
bimurtud Comments: I'm looking at a 330i to buy. How much ballpark it it to fix the internal headbolt buy a good independent shop? Do I want to replace all the unbroken bolts at this point? Is there a stronger updated bolt, or is the problem overtorqueing the bolts on the early cars. Thanks you
April 28, 2016
  Followup from the Pelican Staff: The factory bolts are the best option.

I am not sure what the repair will cost in your area. Call a few shops and ask for a quote. It is also a good idea to have them confirm what the issue is.
- Nick at Pelican Parts
 
Dave Comments: What is the empty threaded area just to the left of where the green arrow is pointing behind the oil filter housing? Is that a broken bolt as well?
December 12, 2015
  Followup from the Pelican Staff: No, there are parts removed from the engine for clarity. That is the mounting bore. - Nick at Pelican Parts  
Euro Bend Cars Comments: My apologies Nick, a lot going on. I needed to know the torque spec and angle of rotation on the 06 325i N52 motor. This should be helpful for others as well.
June 1, 2015
  Followup from the Pelican Staff: No problem. Just want to get you the right info. You mentioned the bolt behind oil filter housing, those should be M9 bolts, correct? That is the torque I supplied. Is that what you were looking for? - Nick at Pelican Parts  
Euro Bend Cars Comments: I forgot to ask, what is the torque specification for the Head Bolt behind the oil filter housing?
May 31, 2015
  Followup from the Pelican Staff: The M9 bolts? 22 Nm. Had to guess at what model you have. - Nick at Pelican Parts  
Euro Bend Cars Comments: Just wanted to say thank you guys for the phenomenal article and detailed description/informative pictures. You guys are great. We mainly buy BMWs, bring them back up to par, give them another lifetime and sell them to lucky new owners. You guys are much appreciated to the automotive community. Keep up the good work.
May 31, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
tome Comments: Thank you. Your tech articles and followup comments are a great service to the DIYer.
March 24, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
tome Comments: Perfect. Thanks for your informative tech articles on valve cover, head bolts, intake manifold, and CCV replacement. I completed the tear down and found no additional broken head bolts. I extracted the broken bolt shown in Figure 1 of your tech article, "Cylinder Head Bolt Testing." My Pelican parts advisor was unable to confirm that this bolt is included in kit 11-12-0-392-547-M17. Could find no additional information online. It is 7 cm long and has an E12 Torx head. Can you confirm that the head bolt kit above contains the correct fastener, or point me to the correct part? Also, my early production N52 engine did not have the metal insulators for the ignition coils shown in Figure 17 of your valve cover seal replacement article. Are these insulators used on all N52 engines?
March 23, 2015
  Followup from the Pelican Staff: I don't have access to the part look up tools. Give our parts specialists a call at 1-888-280-7799. They can figure out if you have everything in your order.

Only plastic valve cover models have the insulators. - Nick at Pelican Parts
 
alex Comments: I need help with oil leak yellow circle
March 15, 2015
  Followup from the Pelican Staff: There is a missing bolt. You will have to replace the bolt. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
808 Comments: my 2006 bmw 325i have major oil leak from the dime size circle yellow colorsee pictureshow to fix?
Thanks
March 15, 2015
  Followup from the Pelican Staff: There is a missing bolt. You will have to replace the bolt. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need. - Nick at Pelican Parts  
dugey Comments: I just bought 2 supplemental bolt kits for cyl head from Pelican they were less then $20.00 for the 2 sets, only needed the one on the outside by oil filter housing, just loosen intake manifold and move back use a pick and back out broken bolt then replace an torque as required,
March 10, 2015
  Followup from the Pelican Staff: Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
garretks Comments: I have a 2007 with the N52kp and I have read that it isn't as common on them. Is this true? Mine has the bolt broken in Figure 1. I wont be able to check the rest until I do my valve cover gasket next week. Jw if BMW made any changes to rectify this on the N52kp? I just bought the car and never would have thought I would be asking about a broken head bolt.
February 27, 2015
  Followup from the Pelican Staff: It happens on those as well. - Nick at Pelican Parts  
Pato Comments: I also had the broken head bolt by the oil filter housing. Removed valve cover and found the Right Side head bolt broken under the cam shaft actuator. Are my options limited to replace this bolt? Can i replace without taking cam shaft out? I've attached photo showing location of bolt.
February 26, 2015
  Followup from the Pelican Staff: Cams need to come out so you can take shaft of aluminum bolt out of head... - Casey at Pelican Parts  
Mjw Comments: Any update on part number in figure 1?
February 21, 2015
  Followup from the Pelican Staff: I am not the best with part numbers. Give our parts specialists a call at 1-888-280-7799 and they can help figure out which part or repair kit you need.
- Nick at Pelican Parts
 
snayko Comments: Can somebody tell what part number is this BOLT right behind the oil filter housing 11127535024 ?
or 11127548799 ?
January 29, 2015
  Followup from the Pelican Staff: I'm having trouble determining what it is. Give our parts specialists a call at 1-888-280-7799. They can help you find the right part.
- Nick at Pelican Parts
 
Brandon Comments: When these bolts snap is it always required to do a gasket replacement. I am in college and my shop says it will be around 2 grand, but the motor is only leaking small amounts of oil and I feel as if new bolts may fix the issue.
March 27, 2014
  Followup from the Pelican Staff: I have done it both ways. A lot of time the bolts do work. - Nick at Pelican Parts  
Ray Comments: Great article about the location and replacement of the M7 aluminum bolt.
February 19, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 

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Page last updated: Sat 12/3/2016 02:23:07 AM