UNDERBONNET

Why ?

People just either forget about the underside of the bonnet or ignore it. To be honest it never seems that vital, especially when there are far more important sections of your car demanding your attention, however it can let down the overall appearance of the engine bay if neglected and it is handy clean because you can spot any potential leaks from the engine bay.

Many more modern cars have some form of felt sound proofing attached to the underside of the bonnet and if so, it might be advisable to either clean around this or skip this part altogether. This is mainly down to the fact that the felt liner will take ages to dry out if soaked.

Preparation

You will need to cover the engine bay, windscreen and wings of the car, as like the Engine degreasing , most of the products you will use have an adverse effect on these parts if unprotected. I use an old decorators plastic dust sheet to protect these parts as it collects the excess water very well and can just be shaken off afterwards. If you do get any overspray or products on these parts, just wash and clean the car afterwards to remove them.

The Cleaning

Thoroughly soak the underside of the bonnet with a hose or Pressure Washer and then spray on the degreaser of your choice, liberally soaking the bonnet and ensuring you work in sections. Then agitate and scrub the sections, working in the degreaser. Leave to dwell for a few minutes and then hose off. Repeat if necessary. This is what 50/50 will look like.

Once you have finished the whole of the underside of the bonnet, pay some attention to any vents or intricate parts. In the example above you will see that the intercooler vent required some protection and polishing, which involved polishing the stainless steel with Meguiars NXT Metal Polish and then I sprayed the whole underside with 303 Aerospace Protectant.

The Finished article