I have started to notice that the intake manifold (silvery bit across front of engine) is getting what looks like an oxide type reaction on it's surface. It's also affecting the bonnet keepy open rod. Tried a quick rub with car wash etc...but nothing is shifting it.

Any ideas what is best to clean it with and then protect it to stop it happening again???

Ta,

/Gav

carb cleaner and a pan scrub...

Assuming that it is made of aluminium, there is an interesting technical item on that material by H Snelson Engineers Ltd here. The various options for cleaning aluminium are listed in that article and are reproduced below:

. Plain water