Griots Garage sells it as "engine shine" or some such. I've been selective in my spraying, only on hoses and stuff...came out OK

 

This is my 1st diesel (700mi) but back when I was a gasser I would spray the clear tire shine on the entire engine, it's liquid form of silicone so it stands up to the heat. The only problem is dust tends to stick a little but just rinse with water and it's good as new.

 

From an owners perspective: Don't use a pressure sprayer. It will push water into places you don't want it (electrical connections) The iron block doesn't care but the hydro end of it sure does.

From a technicians perspective: Go ahead and wash away. The more the better. I make my living off of fixing stuff like this and electrical repairs are straight time!!!!!!!!!!!!!!!

I do not wash under the hood. Water and electrical connections don't mix. Fixed way too many green gremlins over the years. But keep the top of your batteries clean.

 

I spray my engine off with my pressure washer lightly and avoid electrical connections. I do it about once a month. Especially in the winter when the salt spray from the roads tends to work its way into the engine compartment.

I have a 91' Dak that has 175K miles on it which I have been spraying the engine off since it was new. That's 13 years of engine washing with the pressure washer without any problems. About once a year, I will spray the engine compartment down with Gunk engine cleaner and rinse it with the pressure washer.

Like anything you just have to use some common sense when spraying down your engine. Ramming 2000psi of water into your ECU isn't probably the wisest thing to do. Spraying down the firewall, fenders, and block won't hurt anything. After working on engines for almost 20 years, I would rather work on a clean one than one full of crud. I also believe the less dirt stuck to your accessories, the longer they will last. My Dak has its original alternator and power steering pump. The starter lasted to 150K.

If you want some extra insurance, put some dielectric grease on the contacts of all your connectors.

-Muzzy

 

Rinse off with a hose, Armor All Tire Foam, will clean and make the engine comparment shine, been using it since 1998 or so, on my GMC, no problems. also it just rinses off when you need to clean the engine compartment again.