Powerspray is an iffy. Even if you are careful it is easy for it to knock off vacuum lines or unhook cables to where they can be cut by moving parts. A lot of the fears come from the days of carburators which weren't sealed very well agains moisture.
I will do it if I am just knocking off dust/dirt. If it is oil and caked on mess then I'll use any of the engine degreasers except for the "Engine Brite Foamy". That tends to leave a film over overything. Lately I've used the NAPA generic brand on the diesel and it works well. Almost too well. Some of the plastic painted parts will have the paint run a little if I let the product sit for a while.
Whichevery method you use you want the engine warm but not hot. Drip a few drops of water on the exhaust manifold and if it steams it is too hot.
I will do it if I am just knocking off dust/dirt. If it is oil and caked on mess then I'll use any of the engine degreasers except for the "Engine Brite Foamy". That tends to leave a film over overything. Lately I've used the NAPA generic brand on the diesel and it works well. Almost too well. Some of the plastic painted parts will have the paint run a little if I let the product sit for a while.
Whichevery method you use you want the engine warm but not hot. Drip a few drops of water on the exhaust manifold and if it steams it is too hot.
