Bonnet

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P1258 08-12-11.jpg

That big flat panel covering up your engine is the Bonnet. It is the only panel in the whole body that is the same across all models. And yes, it will fit in the back of a Touring.

Dimensions

Length Image
A 1420mm P1258 08-12-11a.jpg
B 1280mm
C 1100mm
D 1190mm

Mechanism

The bonnet is hinged at its leading edge, by the headlights, unlike most other cars.

It's opened by a simple cable mechanism. When the cable handle in the cabin is pulled, it pulls open the spring-loaded latch, allowing the bonnet itself to pop free. Once this has been done, the bonnet can be lifted from its rear corners until almost vertical. It will stand in this position with no need for an external supporting rod.

When closing, two locating pins under the rear corners will drop into guide rails to lock the back of the bonnet closed. A firm press on the front will then lock the bonnet in place again.

If your bonnet isn't opening and closing like it should, learn more about replacing the bonnet cable. If it's completely broken, learn about replacing the bonnet latch.

Sound Proofing

The underside of the bonnet is covered in a sound insulation, which comprises a number of specifically cut foam pads that stick directly to the metalwork.

Over the years, the foam breaks down, moulting all over the engine bay and getting into the air filter. It's unpleasant and messy, but the only solution is to remove the bonnet and strip the foam adhesive with some form of thinner. Surprisingly, Toyota Brake Fluid has been used with great success, but PLEASE remember that brake fluid is highly corrosive to paint work. We take no responsibility for any damage caused by you slapping corrosives all over your paint work.

Sound Deadening

The Diesel-engined 324d and 324td were also fitted with a sound deadening pad. This thick carpet-like board clips to the underside of the bonnet for added sound proofing, to mask the tractor-like rumbling of the M21 engine. Unfortunately, this pad is moulded to the shape of the diesel engine making it generally incompatible with other models.

Washer Jets

Fitted into the bonnet are the washer jets. They're used to spray water for wash/wiper system.

Heated jets were available as part of the Heated package. They required no input from the user; they simply warmed up as soon the ignition was turned on. If you want a set, learn more about installing heated washer jets.

Badge

Sporting its sign proudly like a rhino, the bonnet carries the BMW emblem in the form of a roundel, which is the posh word for badge. The original badge is a metal-backed item with enamel colouring, but it's not surprising for these to have been replaced with cheaper plastic components due to ageing. If your badge is looking past its prime, learn more about replacing the badges.

Removal

Removal of the bonnet is fairly easy, since it's only held in place with a few bolts. But here are some tips to make it easier.

Start by undoing the windscreen washer jet hose from the T-junction in the top part of the bonnet, or from the water container; whichever you find easier.

Now mark around the hinges with a pen, so that you can line the bonnet back up again when it comes to refitting.

Now take out the gas strut. It's just two clips that slide off and a few bolts. Then support the bonnet so that it doesn't constantly fall on you. An assistant would be useful, as they can hold the bonnet while you undo the six 10mm bolts that hold it in.

Once it's unbolted, just lift it clear, being careful not to scratch your wings.