E60: Opening Stuck Bonnet.

PROBLEM:
The annoying turbo whine from my previous post can only be heard while underway and not while stationary, so the bonnet is up and down for every bit of work and test drive. After several such runs, the O/S (driver's side) bonnet latch refused to open. Nearly an hour was spent with a helper pulling the bonnet-lever while I tried to push / pull / wiggle the O/S bonnet up, but it was stuck solid. The front bonnet lip on the E60 (and all modern BMWs) extends right down over the slam-panel / grille and the latches are a good 6 inches up inside it. It's impossible to slide something up through the gap between the rubber seal and pop the latch from outside, as you can with older cars, so I turned to the internet and eventually found a superb solution.

CAUSE:
Yes, this is quite a common problem with the E60, especially when you are working on it at home. The cable splits in two and a separate one runs to each latch. The end of the cable fits through an eyelet on the 'release-switch' and is kept under tension by a plastic collar that fits into a notch in the latch-frame. If the plastic collar pops out of the notch, cable tension is lost and the bonnet-lever simply will not pull the release-switch far enough. Removing the bonnet-lever reveals a plastic-cage with the cable housed deep inside, so yanking that further with a pair of grips won't do either. If you've been working on the front-end of the car and changed the location of the bonnet-latches / slam-panel, even slightly, then there's a high chance the collar will start popping out.

SOLUTION:
There are a few forum threads saying the latch can easily be opened from underneath the car, with the front under-tray removed. This is true, but the E60 engine-bay is so tightly packed there is a bit more to it than that. I have to give props to Kilty1 on forum.BMW5.co.uk, for his amazing guide, linked below:

http://forum.bmw5.co.uk/topic/87159-bonnet-release-not-working/

Getting to the latch requires removal on the front under-tray, both pieces of the O/S brake air-duct and the plastic inlet-pipe that runs to the air-filter. These can all be removed from underneath the car, as shown in Kilty1's guide. He used ramps, though I managed to open mine with the car raised a few inches on an axle-stand. Looking up with a torch, you will just see the latch next to the inner corner of the headlight.

Luckily, my brake duct, inlet pipe and tray were already off as I was working on the car, so I could get straight to the latch and will just show a couple of steps and pics from Kilty1's guide:

1. Reach up and slide a steel-rule or similar slim/flat object into the bottom of the latch, just to the inside of the right-hand spring-wheel [shown on the left in the pic, looking from front]. When the steel-rule is far enough in there should be a small clunk. Now slide the steel-rule quickly out and the bonnet latch should release on the O/S. 

2. The collar doesn't take much to pop out, so to stop it from happening again as soon as you shut the bonnet, wrap a cable-tie round the back of the collar and round through the gap in the steel-frame. It will be solid.