Underbody Carwash Weekly?

[Burch1]

Crazy question I know but is spraying the underbody every week (or few days with unlimited wash pkg.) helpful or harmful to possible rust?
Obviously, during salt season here in Indiana it is beneficial but what about during summer and other dry seasons - help or harm?
Thanks!

 

[Kabanstva]

I would not do it in the summer. What’s the point? If you already have existing rust, any amount of water on top of the already rusty undercarriage is not s good thing. Why do you think dry states like Arizona are full of vehicles with spotless (besides a little dust) undercarriages?

 

[REKCUT]

If you have rust then its working 24/7 to eat up your truck. Carwash will not hurt it and keeping anykind of build up out of nooks will help the truck. Rust on trucks is not from water but chemicals and salt. Your part of the country the rust is from the roads. Not car wash

 

[TXLX100]

If not winter or other corrosive matter in effect, I would just focus on hosing out areas where dirt and debris get trapped and can cause potential rust spots (fenders, rockers, etc).

My experience is that the abraison on painted parts of vehicle is what starts the rust. My LX doesn't have any rust on it, in dry climate with brine used on roads. My 4runner is showing minimal rust on frame / skid plates in certain spots where road abraison has knocked the s***ty paint off.

 

[MyLandy]

I heard a story about somebody on the east coast in the 1960's who was obsessed with their car and washed it everyday. It rusted out in no time, much faster than other people's cars at the time. Unfortunately I have no further details on the story, but I thought it may be of help.

 

[Kabanstva]

If you have rust then its working 24/7 to eat up your truck. Carwash will not hurt it and keeping anykind of build up out of nooks will help the truck. Rust on trucks is not from water but chemicals and salt. Your part of the country the rust is from the roads. Not car wash

Leave a bare piece of metal submerged in water and a second piece of metal (both uncoated) laying outside dry and tell me which one rusts first. Obviously salt and other chemicals they use in the winter months 100% is the reason these cars rust out so much, but hosing down your undercarriage a few times as week, I can guarantee you only accelerates the rusting process. Unless you have salt or mud underneath your truck, just skip the undercarriage washes.

 

[REKCUT]

Wash Your Car to Keep Rust Away (Published 2014)

Cars in Snow Belt states wear a salty film after such a brutal winter. Washing it off is a great way to prevent rust.

www.nytimes.com

 

[alabamatacomaguy]

can you coat with a few cans of fluid film after pressure washing.

Then when you have a free day after the salts been washed off the road and its warm pressure wash under it as good as you can.
Scrap with a metal wire brush and clean as much of the rusty parts off you can and apply your choice of paint product, a rust converter spray can or a por15/rust bullet or even a couple coats of spray paint to protect the metal.

then next winter apply fluid film before the first snow and get a routine of cleaning off salt or road chemicals and reapplying the fluid film every few weeks

from what ive read about northern salt roads is no matter what it will happen but you can drastically slow it by taking care

 

[CLEcruiser]

Another problem to make it more complicated, car washes recycle water so they are pretty much spraying salt water on your car. My research led me to believe fluid film everything underneath, then don't wash the underside at all throughout the winter. Let the fluid film layer stay intact.

 

[06 flstfise]

^^^^^^ what CLEcruiser said. I brush all the rust off in the fall, spray a converter on, paint it then fluid film. Let the fluid film sit the entire winter. Although this winter I did clean the underside and reapply the fluid film due to warm ups, rain, ice and a heavy use of salt by us. I have the luxury of being able to hand wash my truck year round inside and made a under body flush nozzle. I have a hard time believing that once a week visit to the local car wash will get all of the salt and road grime off and out and not just push it further into hidden areas. There are so many little holes and nooks that the salt works it way into. Just to clear the wheel well of all debris takes me a couple of minutes each. Do what you feel is best though, work with a guy who has a brand new truck that he is washing weekly curious to see what happens with it.

 

[biggus]

Fluid Film every fall. Never had any rust, even my 01 Jeep Wrangler is rust free after 17 Iowa and Wisconsin winters.

 

[Burch1]

can you coat with a few cans of fluid film after pressure washing.

Then when you have a free day after the salts been washed off the road and its warm pressure wash under it as good as you can.
Scrap with a metal wire brush and clean as much of the rusty parts off you can and apply your choice of paint product, a rust converter spray can or a por15/rust bullet or even a couple coats of spray paint to protect the metal.

then next winter apply fluid film before the first snow and get a routine of cleaning off salt or road chemicals and reapplying the fluid film every few weeks

from what ive read about northern salt roads is no matter what it will happen but you can drastically slow it by taking care

This is really good advice, thank you!

 

[Kabanstva]

Another problem to make it more complicated, car washes recycle water so they are pretty much spraying salt water on your car. My research led me to believe fluid film everything underneath, then don't wash the underside at all throughout the winter. Let the fluid film layer stay intact.

I have not washed my LS430 even once last year between November and April. Sprayed fluid film everywhere. Checked it late spring and not a spec of rust anywhere. I would not waste my time with undercarriage washes. Drive through some rain at highway speeds in the spring and let Mother Nature wash the undercarriage for you .

 

[Lopott]

buy one with rust and run it all winter long

 

[TXLX100]

Is the most cost and time efficient way to apply fluid film, buy a gallon and a compressed air spray bottle ? It looks like the aerosol cans are $10 each, a bulk gallon is $40.

 

[Kabanstva]

Is the most cost and time efficient way to apply fluid film, buy a gallon and a compressed air spray bottle ? It looks like the aerosol cans are $10 each, a bulk gallon is $40.

Definitely the gallon and spray gun. I don’t like Fluid Film out of the spray can. Comes out too thick and can’t control the spray pattern, plus a lot more expensive.