Ive just had an oil leak fix i hope but the engine is covered in oil. Could i just use a normal power washer to clean it with or would i have to get it steam cleaned. A friend told me i could just use water as its a diesel engine.

Keep the water away from electrical connections (including the alternator) brush some engine degreasant in (Gunk is pretty good) and wash off with a decent pressure washer

 

(those on a petrol garage forecourt are ideal for this        )

you can but the results won't be brilliant. you need to use some form of soluable degreaser first, something like jizer will do the trick, use a brush to work it in then powerwash off, but don't blast your electrics full on or you could end up with problems. might want to use some wd40 on these after just to ged rid of any moisture but not on the alternator innerds

Autosmart g101 and pressure wash

Put plastic bags over alternator / ecu / battery

Then blast away

  If the engine is running during the steam clean/pressure wash keep the water away from the air intake.....if it gets sucked into the cylinders you will end up with bent conrods.

Keep it covered in oil, at least it'll never rust!