On this note be very careful using pressure washers on the rear windows.
Direct pressure will push water past the seals and into your back seat.
Happened to me once and will never happen again.
I humbly share my mistake so that we may all learn.

 

I have the water broom. I have yet to use it on my car. I also have 4 pressure washers. 2 electric and 2 gas. What you have to watch is pressure and volume. Karsher is 1000ish psi and 1.2ish gpm.
My big gas is 9hp honda and 3.9 gallons per minute. It does an ok job with the water broom.

 

I like it.

 

Just curious, what are guys trying to achieve by spraying the underside of you 911s? Other than the rear opening for the engine bay everything is 100% covered by plastic and carbon fiber panels.

When I picked up my 911 last year I went ahead and removed all the panels just because and found everything was pristine other than some cob webs here and there.

That being said, I did clean all the panels in 303 and they looked new for the most part.

@nwGTS - been there done that. You're not alone. I learned pretty quick water intrusion in the rear windows is likely with direct pressure washer spray.

 

I guess just a little OCD about salt up here in the snow belt. I see a little rust from your pics (but not bad). Can I ask what part of the country your car came from and do you drive in the winter?

 

I get it, I am the same way, thus my cleaning of the undercarriage panels with 303 to make them look nice. My 911 sits on a lift in my garage so I am constantly looking at the underside and cleaning it where needed. I just think you aren't gonna get much cleaned via sprinkler under car method. I've also used that approach on my trucks but their undercarriage is typically much more exposed than that of the 911s.

Car lived in CHI for 8 years, had new winter tires on it when I picked it up (CPO'd) last year. So I am sure it's seen it's fair share of salt as there is some rust. It now lives in Dayton Ohio which is smack dab in the middle of the rust belt. Worst rust on the car was at the front body tub seams. I had to cut away the factory seam sealer until I got to unrusted metal, use rust converter in a couple places then reapply OEM seam sealer and reapply paint.

I see you are in Toledo, about 4 years ago I bought a Land Cruiser from a guy in that area and my gosh was it a rust bucket. It was terrible, body rust, frame rust, components rusted. Bought at a super low price and have mostly mitigated the rust issue with years of grinding, sanding, breaking bolts and replacing, etc... Have 160k miles on it now and it rides like a new SUV tho. Everything I learned on the LC made the tiny bit of rust on this 911 a nonissue for me.