Cleaning engines is a bit of a controversial subject to some on here but personally, I prefer a clean one to a dirty as it allows you to see leaks easier....  Others prefer genuine honest dust/dirt to show no tampering but, its your car and your choice....   

Avoid like the plague electrical connections.  You could use plastic bags/cling film around them to ensure all are kept dry.   With engine cold, spray/brush on Gunk or similar degreaser.  Use a brush to work the degreaser into the grubby bits and let it soak.  Carefully use a cold water hose to flush/brush crud off.  Would not advise use of a pressure washer as they are simply far too brutal but I know that others have used them to good success.

Use WD40 or similar water dispersant to ensure electrical connections are dry.

How about steam cleaning instead of a pressure washer?
IW

Steam cleaners can cause more damage.....beware of any thing with a bearing in it....i.e. alternator, power steering pump, aircon pump etc.

I would agree with Hotel21, Using some engine degreaser like gunk is the best way to clean the engine. As hotel21 has stated cover all the electrical componenets then spray on the gunk and rinse. Once you have done this and allowed to dry you could, your own preference, spray engine detailer on as well which also helps protect hoses plus makes the engine look nice and shiney.

TheBoy wrote on 22. Sep 2007 at 20:21:


Nor mine.....unless i accidently go thro a car wash with the bonnet open...

However its suppose to be an MOT failure......with my local council (taxi and private hire).....if the engine is dirty......work that one out!!!......Do customers ask me to open the bonnet so thay can inspect how clean the engine is!! 

Its never failed the MOT for that.....MOT garage has more sense 

But has failed before for being dirty on the outside 

Chopsdad is the expert

Well here's something different and tis what I do....simple and effective.

I use a "gunk"  type spray along with WD40 to spray generally in the engine bay then use my cheap, cheerfull but powerfull air compressor to blow the living daylights under the hood.

Simple, effective and with no "dangers" involved....unless you're a dog, such as ours, coming to investigate what the strange noise is. A quick blast of air up the arse sure gets them flying off up the garden..tis the least I can do baring in mind the amount of air that comes OUT of the dogs arse ???

When I got the air compressor I never really appreciated how many uses they have, in and around the home. It's only a smallish 1.5 litre one...cost about £120.00 but very usefull.