These answer my questions. Thanks.
"Automated Car Wash undercarriage option is a poor and lazy substitute, but better than nothing"
But out of curiosity, why is this?
Simply they just don't do a very good job.
If you think a drive through car wash does good enough. Take a drive in mud. A few days later take to a drive through car wash. Then get under and work on it once dry! You'll see!
I had used a car wash that pre-sprays-soaps in area, vacuumed and hand dry. Very nice and high end. They run through a very nice automated washing system I could watch for behind glass wall. This was in my Pathfinder, which I had for ~13 years. I took biweekly to the same car wash. It ended up with rust issues from road salts. It just did not get all the areas and angles necessary nor any area well enough.
When I got into my 2001 Land Cruiser (The King), in 2003 w/59K on it. I found a coin op car wash with a flexible wand. I'd take a knee pad to get down on and under vehicle and into wheel wheels. It had what appeared to be mild surface rust. Over the years, I found most of it washed away. It looked better 13 years later at 175K than when I first bought it and no rust. Simple by washing thoroughly repeatedly often over time, it got better.
Today I have my own power washer. I found washing my first restores project, took $200 at a coin op. Automated drive through could even come close to cleaning as good as I could myself. Which also is part of my inspection process, as I'm looking over ever inch as I wash. One sees nothing, going to a driving through automated car wash, except shinny body afterwards.
I sold a supper cleans 2011 (Garybird the lost 2012) to a neighbor. Which it comes to me, once a year for service. It's a shame how wheels and undercarriage look. They take to automated car wash and pay extra for undercarriage & wheels.
I've a Duck hunter that comes to me for service. We've been doing some interesting mod in his heavy built 07, to keep AHC working. I mention to him vehicle needs to come to me clean, especially undercarriage. He said he'd cleaned it including undercarriage. Well! I spent 5 hours cleaning undercarriage of dried on mud. Which mud is extremely damaging if left on. I had ~6 shovels full of heavy sand I sweep up after cleaning. At least another 20 shovel full of fine sand, traveled down my curb to city drain. It was the worst I'd seen. I sent him a short video of the mess in my street, where I had washed his supposedly clean rig. I was a bit pissed, as he said he'd cleaned undercarriage. Upon further talks with him. I learned cleaning meant, he took to auto car wash and paid the extra $2 for undercarriage cleaning. In his case I suggested he put a sprinkler under the rig for hours, to soften mud, after these hunting trips. Then get under it with a power washer. If not it's value will go down and his service cost up. It comes to me much cleaner these days.
