I have a 2001 BMW 525i where I just replaced the spark plugs and the cooling system inlet and outlet hoses and the intake manifold gasket. I got it all put back and started up but makes a whining sound and white smoke comes from the tailpipe. When I put it in drive and gave it some gas it hesitates then goes. The same goes for reverse.

  • It sounds as though you may have a turbo leak, like you didn't get the intake fitted properly or the main inlet hose on the pressure side is having an issue. Make sure all of these parts are fitted properly. It's the not so obvious places here which will kick you in the butt. Check anything you messed with to get the intake manifold gasket done. Apr 19, 2017 at 20:44
  • @Pᴀᴜʟsᴛᴇʀ2 Unlikely to be a turbo leak as the 525i used a naturally aspirated engine. May 18, 2018 at 13:55

2 Answers 2


The first thing I would suggest is that you check that the spark plug leads are fitted in the correct firing order. The order of these leads is vital to ensure smooth running.

  • This model of BMW is "coil-on" ignition, so no spark plug leads to be found. As long as the power/ground/igniter wires are arranged properly, that part should be golden. Seeing as how these wires are a given length to get to where the coil sits, I doubt these would get mixed up. Apr 19, 2017 at 20:42

Check the PCV system. In that car its called the CCV. Make sure to get the most recent model you can.

The whistling noise you are hearing is either a vacuum leak or a broken diaphragm in the CCV unit.

  • 1
    Please take a minute to correct this answer. I believe you mean PCV not "pvc" and diaphragm not "diagram". Also, it is always good to back up your answer with some cited source of some sort.
    – CharlieRB
    Oct 17, 2017 at 11:50

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