said by tcope :

Be _very_ careful about introducing pressurized water into the engine compartment. It can damage the electronics.

Hi! I am Bob Osborne with Expert Village. In this clip we are going to be talking about engine cleaning. The couple of things that you really need to be careful of when you are detailing or cleaning an engine most modern vehicles have quite a bit of electronic under the hood, double computers and you got to be really careful because if you get one of these computers wet and it shorts it out, we are talking about serious replacement costs into the thousands of dollars. So the steam cleaning of an engine is really no longer practical. I haven’t steamed cleaned engines for quite a long time. Instead I just used a regular garden hose, degreaser and brushes and I just get into the engine real lightly and carefully so that I do not introduce a lot of high pressure water or steam to the engine, which can cause problems.