N55 vanos bolt broken

image Do you notice anything wrong in this picture,,,take a closer look at the intake vanos unit,,,,the intake vanos unit not sitting straight,,,,car got towed in from an auto body shop,,,engine won’t start,,,,engine turned over ,,,,but no start,,,,I noticed when cranking the engine,,,,the engine spun kind of fast,,,,like there was no compression.image You can see the vanos not sitting straight ,,,,and the vanos bolt is sticking out.image Heres the vanos bolt,,,notice the bolt threads are missing,,,the rest of the bolt is stuck inside the intake camshaft,,,,so during the accident the oil cooler got damaged,,,,and all the oil ran out of the engine while it was running,,,so the first thing to go was the intake camshaft locked up inside the cylinder head,,,,breaking away the vanos bolt,,,,I was unable to turn the intake camshaft inside the head.,,,time for a new engine if the insurance company buys it.

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24 Responses to N55 vanos bolt broken

  1. BMW Enthusiast says:

    Hello BMWTechnician. Today my check engine light came on when I started my car. Got the codes 2A7C – VANOS, inlet, cold start and 2A82 – VANOS, intake, variable cam control test. These are the symptoms. The engine has a loud ticking/rattling noise at 700-1500 rpm. It goes away at 1500 RPM and above. When starting the car, the rpm will jump to 1000 RPM once, and then it will go back to normal. This happens every time I start it. I tried changing VANOS Solenoids no help. Heres a link to the rattling sound. The rattle is not as loud in the video. Its a lot louder when I revv it to 1k.

    I appreciate your help!


    • So you replaced both vanos solenoids ,,,,the next thing is to remove the valve cover and check the intake vanos units,,,,that noise could be the vanos unit coming apart,,,,the 4 bolts that hold each vanos unit together sometime break and come apart,,,I have some pictures in my blog


  2. BMW Enthusiast says:

    Thank you for your input! Dropped it off at the dealer today. Told me they have to replace both VANOS units and also drop the oil pan to get the broken bolts. Under warranty thank God. How many hours did this job pay you under warranty? Did they pay you enough to finish?


  3. BMW Enthusiast says:

    Hello BMWTech, when they opened up the valve cover today the said that one of my cylinder head bolts were broken. They told me that while the valve cover is out, they will only charge $275 for the 4 bolts. Is this a common thing on the N51 motor? Or are they just adding up charges?


  4. BMW Enthusiast says:

    Hey BMWTech. So on my 2011 328i Coupe N51 Engine I recently had broken VANOS bolts. They replaced both VANOS actuators and also dropped the oil pan to remove the bolts. Everything runs good now. However, ever since I got the car back from the dealer, the car feels like it has a lot of body roll and does not handle as good. Any idea why? Is it because they did not put things back on properly? Thank you.


    • That’s doesn’t make any sense,,,but they had to drop the front subframe to remove the oil pan,,,,maybe they forgot something on the front end after replacing the oil pan gasket,,,,I don’t know what it could be,,,,,when I do the job I just lower the front subframe with all the suspension component still attached,,,I don’t remove any suspension parts,,,,,maybe have them recheck out the front end for you


  5. Ian says:

    Good day BMW Technician, how are you today? I need some assistance in diagnosing a problem with my 2011 535i X-Drive. It was fully serviced 5 weeks ago by my mechanic and recently, on a long trip, I heard a rattling noise coming from the engine. I took it back to the mechanic who scanned it and got the following codes: 133B04, and 133E10. Both of these suggest a failed or failing Valvetronic Sono motor, but after watching a few videos and hearing cars with similar noises, I think it MAY be something more serious like a Rod Bearing failure.

    My question is, would a failed Valvetronic Sono motor sound similar to Rod bearing knock? My mechanic may want to “explore” to find the cause of the noise which will take up costly hours, and I’d like to avoid that.



    • The servomotor does not sound like a rod bearing noise,,,the rod bearing noise should be more of a knocking noise.


      • Ian says:

        Good day Sir,
        Thanks for taking the time to reply. I have a few more points as my issue hasn’t been resolved. I decided to get a second opinion as the first Mechanic wanted to go on a fishing trip in my car’s engine. Here the Synopsis:

        1. I replaced the intake servo motor but the a rattling sound persists.
        2. The mechanic said after replacing the servo motor, he ran the car, pushed it really hard and was certain he heard no noise.
        3. When I took it from him, within 20 minutes of driving I heard the same rattling noise when accelerating.
        4. The Mechanic said it’s certainly not the rod bearings or piston slap, and the problem may be an oil pressure issue as the vanos requires good oil pressure to work.
        5. The vanos code keeps coming back (adjusting too frequently and vanos shuts off)
        6. Since replacing the vanos, the car has an oil leak.

        1. Can a scanner identify which Vanos is bad, intake or exhaust? I’m thinking the wrong Vanos was changed.
        2. Do you think a different brand oil may solve the issue? I was advised by the second mechanic to use Amsoil. I purchased Liqui Molly 4200 Top Tech oil and gave it to the first Mechanic for the oil change; I only use liqui-molly oil.


      • Ok you said you replaced the intake servo motor are you talking about the valvetronic servo motor?,,,,next you said you replaced both vanos unit now I have seen people switch the intake and exhaust vanos units during repairs many times,,,,next you could try a different oil it wouldn’t hurt,,,,,and yes a good scanner can tell you which vanos unit is bad.,,,,I hope this helps


      • Ian says:

        Hello Sir,

        I greatly appreciate your response. The mechanic has changed the oil and was very excited that the noise stopped when he ran the car after the oil change. He said he pushed it really hard and heard NO noise. He called me and sounded very excited that the problem was solved, but this was short-lived as the noise returned. He said the noise returns when the engine heats up (operating temp), and this problem causes the Valvetronic Servo motor to shut down (Codes 133b04 and 133e10). He strongly advised not to drive the car with these fault codes or there’s a risk of engine damage.

        The noise sounds very much like this: https://www.youtube.com/watch?v=rNOZviSBe6w , so I’m totally confused why the Mechanic says it’s not Rod Bearings.

        He’s the second mechanic to attend to the problem, and it has confused him. After replacing the Valvetronic Servo motor, last week, and the noise returned, he was convinced it was an oil pressure problem. He’s convinced it’s not rod bearings or piston slap, but may be an oil pressure issue as the Valvetronic Servo motor depends on oil pressure to work well; that’s why he changed the oil after replacing the Valvetronic Servo motor.

        The first mechanic de-carbonized the engine, he encouraged me to do it due to the condition of the old spark plugs and he even encouraged me to push the car even more to prevent carbon build-up. What’s your opinion on de-carbonizing this engine? Could this have contributed to the problem?

        I’ve decided to take the Car to a BMW dealership for a diagnosis; this should have been my first course of action which I really regret not doing.

        Thanks for your feedback.


      • That noise in the video sounds like a rod bearing,,,but you said the noise comes and goes,,,,,also when they changed the oil and filter did they see and metal inside the filter?


      • Ian says:

        Correct, my Mechanic said he didn’t hear it on the test drive after the oil change, and after the Valvetronic motor change 2 weeks ago. The noise happens when the engine heats up and it also throws the vanos off. No metal in the filter.

        Hopefully the Diagnosis at BMW can identify the problem.



  6. ayan says:

    hey bmw tech , man i have the same situation on my n55 right now crankshaft turns and exhaust camshaft as well intake camshaft is locked cannot move it is there a fix for this or motors completely shot … bought car from auction but dosent look like any damages to the and parts under camshaft from what i can see but could be hidden … your advice would be much appreciated ty again in advance


    • What you can do I don’t recommend it but I have seen it done,,,remove the intake camshaft and look at the camshaft bearing journals and see which ones are damaged and inspect the camshaft journals,,,I have seen people take fine sandpaper and sand the bad journals to make them smooth again so the camshaft can spin freely again,,,good luck


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