Is it safe to clean my engine with a pressure washer?

Many other people would say yes, I’ll say no for the following reasons.

1. Although you will get away with it most of the time, the damage you could cause can be REALLY expensive to fix. At the very least it can cause great inconvenience.

2. There is no good reason to have a spotless engine. Most of the stuff which makes it look dirty is oil, and oil actually protects your engine. And nobody ever looks under there anyway. So unless you are selling your car, or left the oil cap off, or have some other specific reason to clean your engine, it’s really not worth trying to keep it spotless.

3. It is very possible to clean an engine bay without using a pressure washer, and without using water for that matter.

So you see my point? Why take the risk?

As I already said, nobody is likely to look under the bonnet of your car unless you are selling it, so there is no point in trying to keep it spotless all the time. So as cleaning your engine bay is going to be for a sort of special occasion, it’s worth taking a little extra time doing it. The method we have found to be best is to clean it by hand using a light oil such as WD-40. However, if you have some reason why you really must use a pressure washer, then take the time to wrap anything electrical in cling film and only use the pressure washer on the parts where you can’t reach to do it by hand, and never spray water onto electrical parts.

Once you have done removing all that dirty oil, ensure that you re-grease any bare metal and vulnerable areas to prevent corrosion.