My father owned a car wash for 5 years, and I had the pleasure of "helping" him from time to time when I was younger.
Car washes are extremely maintenance intensive businesses. You have people break the spray wands, dump garbage, try to break into the coin room (had to replace the door twice due to crowbar damage), replacing pumps, re-supply soap and finishing product, empty vacuum bins, etc. Every couple months you have to "dig the pits" - that's the drain areas in the car wash bays. People fill these up with sand and debris power washed off their car and it's about a 750 gallon hole in the ground half full of sludge and junk, not quite as bad as cleaning out a lift station. We would get in there with shovels and haul it off to the dump.
He literally had someone go out and check on the place for at least 30 minutes per day to make sure all the bays were operating as expected, make any repairs, and would weekly collect money. Money collection day was always a fun one - would arrive during off-peak hours with a friend and a Colt .45 for security to carry $400 of quarters out of there.
Success of this business is solely whether you have a good maintenance man - my dad's uncle did it, he liked fixing stuff and had all the time in the world which is the only reason it worked. If you hire professional outside help I suspect would eat heavily into your take home.
I would look to lease it as a contingency to close, or sell it via fire sale.