depending on how well the engine bay is designed (you're on your own here...), most of the sensitive electronics ARE covered quite well, and some even have o-ring or other gasket type seals.
I have been quarter-car-washing engine bays for 30 years and have never had a significant issue other than a boatload of steam upon restart. My older cars with regular distributors (a 70 Olds/GM 350 2bbl as an example) often coughed a bit, but cleared up in a few seconds. THAT was a clue that the cap o-ring was shot and needed replacing, btw...
My wife's 70 Gremlin (yes, she bought it before we married, and yes, it was an ok car...) absolutely DIED when it SMELLED water, so I don't think I cleaned that engine too often. Besides I was in school at the time and we didn't keep the car long anyway....
Sometimes belts will squeal especially if they are old and somewhat slick. An older Chrysler once started squealing and never would shutup until a bit of belt dressing was applied, and them it never squeaked again, even after repeated washings. (we were on a roadtrip to FL, hit a skunk at night and I had to heavily wash the car and engine bay to reduce the "memories" as much as possible. the belt squealed for several hundred miles or so until I found an open parts store and some dressing)
I've never seen a need to clean fuse boxes or the innards of an alternator.....common sense is helpful on these things.
I use the low pressure setting, 1st with the "engine cleaner" (smells like simple green usually), then low pressure soap and then low pressure water rinse. I don't force it into places I shouldn't and just generally use common sense. I concentrate on "back-flushing" the radiator and AC coil, the front of the block and the firewall and other places that gunk accumulates along with valve covers, etc.
It just makes a car much easier to work on, and problems easier to spot.
I have been quarter-car-washing engine bays for 30 years and have never had a significant issue other than a boatload of steam upon restart. My older cars with regular distributors (a 70 Olds/GM 350 2bbl as an example) often coughed a bit, but cleared up in a few seconds. THAT was a clue that the cap o-ring was shot and needed replacing, btw...
My wife's 70 Gremlin (yes, she bought it before we married, and yes, it was an ok car...) absolutely DIED when it SMELLED water, so I don't think I cleaned that engine too often. Besides I was in school at the time and we didn't keep the car long anyway....
Sometimes belts will squeal especially if they are old and somewhat slick. An older Chrysler once started squealing and never would shutup until a bit of belt dressing was applied, and them it never squeaked again, even after repeated washings. (we were on a roadtrip to FL, hit a skunk at night and I had to heavily wash the car and engine bay to reduce the "memories" as much as possible. the belt squealed for several hundred miles or so until I found an open parts store and some dressing)
I've never seen a need to clean fuse boxes or the innards of an alternator.....common sense is helpful on these things.
I use the low pressure setting, 1st with the "engine cleaner" (smells like simple green usually), then low pressure soap and then low pressure water rinse. I don't force it into places I shouldn't and just generally use common sense. I concentrate on "back-flushing" the radiator and AC coil, the front of the block and the firewall and other places that gunk accumulates along with valve covers, etc.
It just makes a car much easier to work on, and problems easier to spot.