I probably wouldn't on the alternator unless I had it apart. I don't know that it would cause a problem, but my imagination says little pieces of metal and an electric generator would be bad.

 

I've never covered alternators and never had a problem. Covering the PS cap is a good idea tho, water will get in the breather hole and into the fluid. I then take the cap off and clean it in the garage sink. If I have a plug that fits the reservoir I'll replace the cap with that so the top of the reservoir gets clean, otherwise I just wipe it clean after the washing.

Someone said 'don't worry about the sensor connectors, they're well sealed'......hahaha, not always. Some water got into my ICP sensor connector and when I rolled onto the freeway on-ramp & floored it (all stock so it's kinda slow) it took off like a rocket leaving a black smoke screen behind me. The revs jumped so quick I redlined 1st before I could lift the throttle. Then it started bucking and died, I thought I'd broken it. Once the connector was dried all went back to normal. I've got 428k miles so my connectors are probably a little looser than other's.

I've had issues with other vehicles and water getting into connectors, but it's fairly rare. My Porsche, Jag, & Mercedes incidents (just one of each) stand out as scary ones; running like crap, dieing out, and/or throwing codes 'till they dried completely, sometimes a couple days. 'Normal' vehicles are usually fine.

When I worked at International the washing procedure was a hot running engine and high temp pressure washer, nothing covered and blast the heck out of everything. I don't recall using any cleaners, I think the hot high pressure water took care of it all. I wanna say the heater was set to around 200F. They called it a steam cleaner, but really it was just super hot high pressure water. A couple times the heater wasn't working and it made an obvious difference in cleaning ability. The fleet I was in charge of (lease and rental trucks) was mostly DT466 and some DT444 (aka 7.3 PS) with a few others thrown in and I don't recall ever having issues, but these were fairly new, generally nothing more than 4-5 years old. Since everything was hot they were usually completely dry by the time they got from the wash bay to 'my' side of the shop.

 

You will not see me pouring, spraying or using cold water (or hot water for that matter) on a hot running engine. Too much of a temperature variation for me to be comfortable with between the water and hard metal parts.

The use of hot water is a proven benefit to cleaning engines. That is why I take the approach of cleaning the engine when it is COLD, then letting it idle for a few minutes, then taking it on a short drive. This will loosen the dirt and grime for next time and slowly dry the engine bay out warming the water over time instead of a blast of water on a hot engine.

YMMV

 

A warmed up running engine and 180-200 degree water won't have much temperature difference. Hot engine and cold water, I wouldn't do that either. I wash my engines cold.

 

I can't argue with y'alls results as they look great but I'm a simple guy. I use the car washer sprayer with engine cleaner. It's lower pressure than my pressure washer at home.
I actually have the engine running when I wash it - I'd like to know what part is wet if it should start running bad so I can dry it out.
I ride my Harley and have hit cold rainstorms many, many times, didn't hurt anything so I don't worry about that kind of stuff anymore. I can't see any difference between running down the road and hitting a water puddle filled with melted snow.
Don't hit the alternator with water as the damage it will cause is to the bearings of the rotor. Everything else in the alternator is basically water proof.
You have to use some common sense when using a pressure washer though.

 

 

That discolored degas bottle must drive you nuts...

Nice detail work!

 

Probably not until you pointed it out

Nice work on the cleanup

 

 

 

If you do find that black plastic trough, let me know the part number and source. Mine has seen better days too and I just broke the bracket where the manual transmission master cylinder fluid reservoir attaches to. I have it zip tied in place and it screams at me every time I open the hood.

 

I had my engine bay looking like this when I first got my truck. I live on a dusty road and there isn't even any point right now. I still wash it off occasionally but it seriously gets covered the first time I leave my house.

 

My wife always looks at me funny when I say that I am washing the Subaru, even though we are getting ready to drive it in the rain. I tell her "I getting it clean so that when it gets dirty it is easier to get clean again". That is normally followed with something like "it makes sense in my brain, I love you and I will be in the house soon".

 

I cleaned the valley of my sons truck the other day and I have to say I got it spotless with in a few minutes. Not sure if it was the best way but it worked. We were trying to find a pesky leak so I used a couple of cans of brake cleaner. The engine was cold but I sprayed down really good and what didn't come off with the spray came off when I used compressed air. Left it spotless. Found the leak too.

 

That stuff works well. I read an article in a motorcycle mag where a guy used some of that to clean some parts and then had to do some welding on them, ended up getting phosgene gas poisoning. Bad stuff. Had permanent health damage. Doubt that could happen unless you are getting it to extreme temperatures - e.g welding.
Just throwing that out to the welders around here.

Now back to your normally scheduled topic.....