By on November 10, 2011

BMW hasn’t offered a four-cylinder engine in the U.S. for quite some time, so I was eager to check out their new 2.0-liter twin-scrolled turbo. A Z4 so equipped arrived in my driveway today.

Not to give too much away prior to the full review, the new 240-horsepower engine works very well when paired with a six-speed manual in the 3,263-pound Z4.

Then I broke it.

As is often the case in the post-Lexus era, an engine cover hides the goodies. Knowing that some of you would like to see what’s going on under the cover, to serve the common curiosity I pulled it off. The cover readily pops off the left side of the engine, but some vacuum lines restrain it on the right side. Belatedly I discover that BMW hasn’t merely fitted a cover—they’ve attached a vacuum accumulator to its underside. Why? Beats me. I’m not going to detach any lines, so I just hold the cover up to the side while grabbing a quick photo.

Yeah, BMW’s new four isn’t a pretty sight. This mill badly needs its cover.

Replacing the engine cover proves a bit difficult. My first attempt misses the attachment points. Popping it back off for another attempt, I hear a “whoosh” as a vacuum line pops off of its fitting. My second attempt hits the attachment points. I then find the loose vacuum line, find a fitting that’s missing a line, and reattach the line.

Start the car up, drive a few blocks, and the yellow CEL lights up. Boost is either severely restricted or gone. (Though, surprisingly, the engine still doesn’t feel terribly underpowered. Perhaps this is what the lesser-engined Euro-market BMWs feel like?) Back in my driveway, I do the smart thing this time, and reference a photo I took before removing the cover. Seems two lines had come loose, and I’d only reattached one of them, and to the other’s fitting.

I fix this, but the CEL won’t go out even after I stop and restart the car a few times. I resign myself to a trip to the dealer to have the light reset. The next morning the light is still there when I start the car to head to the dealer. I drop by the kids’ school first to drop off some things for one of them. I then get back in the car, restart it, and—with the dealer next—no light and full power. Perhaps the car needs to be driven a certain number of miles before the computer concludes that the earlier problem is gone?

Needless to say, I’ll be more careful next time I pop off an engine cover—they’re not just for covering up the engine anymore!

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47 Comments on “The Dangers Of Lifting Engine Covers...”

  • avatar

    Just another example of BMW’s determination that you will go to the dealer. You will not touch the engine. Ve haff vays of making you obey.

    • 0 avatar

      I picked up a used miata from a bmw dealer a couple weeks back. During the close they asked me if I would ever consider a BMW. I told them that while I like the cars, I like to do as much as my own work as possible and BMW has made that nearly impossible (have to go to the dealer when you get a new battery?!?) for the last several years.

      Of course I’m guessing that little of BMW’s current target market wants to get grease under their fingernails.

      • 0 avatar

        Funny you mention the battery. It’s not just BMW, Mercedes is just as bad if not worse.

        Recently changed the battery on an ’07 R500, which was an adventure I’ll never repeat. First, the batt. is located under the passenger seat and required me to RIP the carpet (it was perforated fortunately) to access. Then when I finally gained access I had to be -EXTREMELY- careful upon removal because there was a very important-looking wiring harness which could be easily bumped (and damaged) when lifting the battery out. Finally got the new one in and congratulated myself for making the effort.

        Unfortunately, that was only the beginning. You see for some reason, Mercedes chose to use some sort of software-based synchronization scheme for the power windows, sunroof, and hatch which requires manual resync. after battery replacement. Despite following the manual instructions, I managed to “brick” the sunroof in the open position. Also the hatch failed to operate. Oh yeah, I also got an SRS light in the cluster.

        Went to the dealer and explained this. The service advisor didn’t actually say anything at first, but the gleam in his eye indicated that he knew EXACTLY what the situation was, and he sheepishly admitted that it’s basically impossible to do anything with this vehicle other than washing it without the service manual. Fortunately I didn’t actually break anything and, wonder of wonders, the dealer didn’t even charge me to reset everything.

        After two BMWs, one VW, one Audi, and the R500, I’ve concluded that German cars are just not worth the hassle. I know full well they are exciting to drive, look nice, and are solidly built, but owning a high-end car SHOULD NOT be more of a pain in the ass than owning a Corolla (at a fraction of the price). I’ve worked on cars longer than I’ve been able to legally drive them, and the only ones I’ve ever had problems with are the Germans for some reason.

        In sharp contrast, changing the battery in my mom’s Lexus and my Infiniti only required the clocks to be reset.

      • 0 avatar

        As an MB tech I can tell you, your a brave soul to attack an R-Class (or M/GL Classes) battery under the passenger seat. They SUCK. The carpet has to be ripped and I usually end up removing the seat. (The SRS light is from the weight sensing sensor in the seat.) And then I have to use the MB computer to reset any fault codes.

      • 0 avatar

        @ Dawnrazor – I wonder if a slave battery plugged into a power outlet (ie cigarette lighter socket) would avoid needing to reset everything?

        I too hate the overcomplication of things that don’t need it. Eg some cars where to change a headlight globe you have to remove the front bumper – and this is on Euro cars where some countries require you to carry spare bulbs by law!

      • 0 avatar

        I’m not so sure the battery needs a dealer visit like V-dubs and maybe MB’s. I know on my E46 it doesn’t, I replaced the battery myself with a Wal-Mart replacement that fits perfectly and has all of the aux connections. As for serviceability being overly complex this is total BS. All new cars are more complex than the older ones but as a DIY guy who tackles everything short of a engine overhaul my BMW is the easiest car in my fleet to driveway service. Front brakes – 1 hour, Rear brakes 1 hour, Cooling system overhaul – 2 hours. Control arm bushings 2 hours. Oil change, topside filter, couldn’t be easier. Only thing I had a shop do was the starter because I didn’t have time and it’s much easier with a lift. Two cars I won’t touch to service that I have owned or own, Honda Element and Ford F-150, both suck to maintain.

    • 0 avatar

      Working on a new BMW isn’t bad if you have the right tools. You can get a Bavarian Technic tool for a couple hundred bucks. It hooks into the car and you can read and clear any code, monitor the output of any sensor, activate different devices, log data- pretty much anything the dealer can do, including resetting the battery monitor. When there’s a problem, it’ll tell you what it is and if it’s currently present. Makes stuff pretty easy.

      You don’t have to go to the dealer for everything- you just need another tool in the toolbox. If it saves you a single dealer trip it has already paid for itself.

      • 0 avatar

        But look another ultimate driving machine innovation…half a check engine light!!! Now if you only knew which half?

      • 0 avatar

        A manual from Bentley can be a huge help as well. For me, the dealership relationship has been getting better. My local BMW dealer has started giving me a 20% discount on parts, so lately I’ve been going to them rather than the “net” and Pelican. I pull up diagrams on their website and order the parts from the diagram. They send me an email when the parts are ready at the counter.

  • avatar

    Bet something as traumatic as this never happened with the lowly Mazdas you usually review! ;0)

  • avatar

    I bet there is no dipstick for the oil, BMW was first to eliminate that unneeded feature /sarcasm on

  • avatar

    There is an engine in there?? Love the kink in the hose right in center front of the photo, that goes downward.
    Too bad, I used to be a big fan of Beemers.

  • avatar
    A Caving Ape

    Haha, sounds like just another day of out-of-warranty VW ownership.

  • avatar

    Wow that thing is ugly. I much prefer my RSX-S, which has a IM cover and coilpack cover. What ever happened to just making a good looking angine with small covers in the right places? I can’t think of a bad-looking honda mor nissan 4-banger

    Picture is of a JDM K20A, but my K20A2 looks similar since I painted the valve cover wrinkle red and got the JDM coilpack cover.

  • avatar

    Right now there is a red blinking light, cubicle 1324, floor 7 of the Munich Tower.



  • avatar

    There are hard codes and soft codes. The hard codes will keep the Check Engine Light on until they are reset. The soft codes are more of a warning for less dire problems. In the past, the soft codes would reset after a few engine starts.

  • avatar

    Yup it usually takes at least 2 “cycles” w/o the problem occurring for the CEL to go out. The code is still in there and will take 50 or so cycles before it drops off.

  • avatar

    Reminded me of time spent on an old SAAB 900 Turbo “searching for boost”.
    The old stager was 17 years old at that time when I bought it for the mighty total of 155 bucks, and it was much more than just 2 loose hoses for sure. Got it run properly in the end – it does help when the car is relatively simple and you having wiring/hosing diagrams at hand.

  • avatar

    Go to the dealer to clear a code? The labor cost for that will be twice as much as a cheap OBD2 code reader/clearer (assuming that disconnecting the battery either doesn’t work or causes other problems).

  • avatar

    That engine looks about as sad without its cover as a hermit crab does without its shell. Doesn’t mean it isn’t a great engine, though.

  • avatar

    +3200 lbs for a two seat roadster?!? Sure, it has a power retractable hard top, but holy crap that’s the weight of many sedans and spitting distance of some wagons!

  • avatar
    Educator(of teachers)Dan

    Makes ya want to go buy a 1966 Impala.

  • avatar

    What!? My 2007 Pontiac Solstice GXP has a turbo with a 2.0L I4 engine that puts out 260 HP stock and with an ECM flash you get 290 HP. Car weighs about 2,900#. New for under $29,000. For the price and weight of the BMW one can get a Corvette instead.

  • avatar

    Under the cover, that engine resembles a 1975 Honda Civic – yuk.

  • avatar

    You should pick up an OBD II reader Michael. A cheap gets the job done one with no frills one can go for around 30 dollars at sears. With the broad range of things that can set off the CE in a modern vehicle it’s well worth it.

    Also my local AutoZone does CE diagnostics for free, not sure if they reset the light though.

  • avatar

    If there’s literally no engine maintenance that can be (or allowed to be) performed by the owner on a new German car, what’s the point of even having access to the engine bay?

    Frankly, I see a day in the very near future where the hood release on all new German cars (eventually followed by everyone else) will be electronically restricted to the manufacturer’s own service department’s exclusive access, and control will be relinquished automatically only after the vehicle’s ECM has determined that the warranty mileage/date has expired.

    The sad thing will be it will not trigger any protests from most owners.

  • avatar

    Of course the engine layout is ridiculously complex. Isn’t the whole point of owing a BMW to brag about how much you spend on maintenance?

  • avatar

    Putting the cover back on didn’t do much for the looks. That engine is downright ugly – with or without the cover.

  • avatar

    “Vacuum reservoir for the wastegate valve permanently connected to the engine cover.”

    From BMW Technical Training for N20 engine.

    Having read that very long article, I’d be afraid to turn the engine on! Quite the technical exercise. At least BMW have gone to great lengths to properly vent the engine and to filter oil out of the PCV gas stream, so coked up intake valves aren’t likely. VW/Audi direct injected engines are not so lucky, and use an older type DI system anyway.

  • avatar

    Hey. I wanted to ask something. When you take off these engine covers. there are many wiress and other kinds of cables to be seen. I just wanted to ask why they make them this way. when you look at older cars for example lets just take a miata or sth, you didnt have all these wires on top of the block and under the cover. Why do these new cars have so many complicated wires? please help. I am really frustrated because i havent got an answer to this.

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