Quote:
Originally Posted by bbnks2
I've never heard of any kind of failure associated with the oil control valve. It's basically a vanos solenoid. Pretty simple device actually. If it fails it just means MORE oil pressure will be delivered to bearings rather than bypassing to the pan to reduce pumping losses. Oiling is actually simplified with the N55.
The electronic water pump is actually pretty awesome and has more than adequate flow. Ability to continue cycling water after the engine has shut off (turbo timer) and ability to control cylinder head temps for different driving conditions. Actual oil and water temps have more to do with DME logic than it does the pump itself. I have all stock components and my car sits at 210-220f oil temps... 180-190f coolant temps. What's wrong with the coolant pump? Cost and high failure rate is probably the only reason why they did away with it...
I honestly don't believe that N55's have any more oil related failures than N54. You just don't have N54's being serviced by shops anymore since they are essentially $7k third owners cars at this point... You scrap a car like that when it blows up. N55/N54 in general produce lots of low end torque which = high wear on the bearings.
I also don't believe the Teflon seals BMW switched to with the N55 completely solve the intake cam oiling issues. I think it helps prevent the seal from eating into the cam ledge but now how long does a Teflon seal last before it gets deformed or stretched out and causes the same issue?
JonEQuest To check the intake cam, just remove one of the caps. check the wear. Replace the cap using exact torque specs or you can cause the intake cam to bind up. Then check the next cap... no need to remove the cam altogether. That is a ton of extra work. If you do want to tear it all down, the only thing you really need to keep in mind is that you want the engine locked at TDC and install the cam with the label facing up. This ensure you don't mash valves into pistons. Read up on newtis.info.
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My reason for saying N55 is more likely to break down than an N54 is that I have rebuilt an N54 recently and it seems I am partially rebuilding this N55 now. The n54 has way less parts in the intake cam side which means way less parts that can break. The N55 has about triple the parts which means higher chance of failure. That is just simple logic on any mechanism. The N54 has one intake cam with one set of bolts holding it and the cam ledge down, and after that it was just rockers and lifters. Now the N55 has electronic valves, worm gears and a few more sets of bolts holding everything together, etc thrown into the mix. I personally know of several N55 owners who have has upper head issues and I don't know of anyone who had cam issues with the N54 except things like a dirty or bad VANOS solenoid. I plan to just pull one cap at a time to avoid any issues but would be surprised if I don't find damage somewhere.