automatic car washes / how do you deal with winter salt from roads

If you treat the underbody with blaster surface shield every year, it’ll essentially never rust.
I hope that's true. I keep hearing good things about it!

I recently picked up a Honda Fit and it has just small traces of surface rust.... Only 22,000 miles! I gave it a real good coat of Surface Shield everywhere I could.
 
I do the automatic wash at the local Petro Canada. I buy a book of 7 washes on a card and that works out to around $12 CAD each. I Krown and do my own touch up with various RI products, whatever is thick, well respected and on sale.

IMHO, there is no perfect solution for most Canadians or Rust Belt America, you store it outside, the engine & drivetrain feels the cold, but the body lasts longer. I keep mine in a garage with my wife's car and my motorcycle. I don't heat the garage but the place never really gets any lower than +3C so my engine warms up fairly quick. With the recent supply chain stuff and the trend for OEM's to stop carrying parts past 10 years, what will be our situation with non rusted but obsolete 10 year old cars?
 
Salt here isn't as bad...no rock salt uses but they do brine the roads for pretreatment in the fall, and you pick up salt in parking lots depending on where you go. I pay for monthly unlimited touch less washes with underbody. I also heat the garage to 50, and although I know it's hurting I'm not willing to park outside in negative temps, scrape and brush, etc.
 
On the rare occasions they salt the roads here, once it has blown away I'll run the white beater Explorer through the local "Bubba's" brush car wash which has an undercarriage wash option. I don't like running the green Explorer through there because some of their chemicals leave a weird residue on the paint, but I don't generally drive it if there's salt on the roads...ironic since it's the 4WD.
 
It's like this-yea automatic car washes cause clear coat scratches. The "touchless car washes" in addition to being as rare as unicorns put a very abrasive soap on your paint. S0-I go to automated car washes and get the under carriage option and I will pay for paint correction when it (scratches) get bad enough. In the summertime I wash my wife's Hyundai myself.
 
On the rare occasions they salt the roads here, once it has blown away I'll run the white beater Explorer through the local "Bubba's" brush car wash which has an undercarriage wash option. I don't like running the green Explorer through there because some of their chemicals leave a weird residue on the paint, but I don't generally drive it if there's salt on the roads...ironic since it's the 4WD.
It's the recycled water that leaves a residue. It's harmless.
 
Car washes have recycle where they collect the run off , settle grit into tanks and spray the fine silt and salty mixture diluted with fresh water.

My first engineering task out of college was a site design for a car wash.
 
Does washing the car in the winter even help?

If you are running through an uncontrolled automatic wash you're dissolving the salt in the water and possibly forcing it into places that normally wouldn't even be exposed.

Do you think these places are generous with their water and all of it gets washed away?

Afterwards your car cannot dry easily since its the winter. Corrosion forms in the presence of moisture, salt accelerates it.

Even if you manage to rinse the salt off, how long will your car stay salt free?

I don't know, periodically washing the car in the winter to prevent corrosion just doesn't make sense to me.

It makes sense to oil spray it to lock the moisture away and leave it until spring.
 
I have never been able to get myself to purchase a wash pass. Just seems like a logistical nightmare when winter is over, plus the local washes are all soft touch, and whenever it’s prime time to wash(dry, sunny winter day) the line is always long.

So what I do if weather allows is I’ll rinse in my own driveway. Underbody is a must. Main area I focus on is right below the rockers and the area from rear suspension and back. If the temps stay below freezing for more than a week I’ll take it to the self wash and do a through rinse.
 
Does washing the car in the winter even help?

If you are running through an uncontrolled automatic wash you're dissolving the salt in the water and possibly forcing it into places that normally wouldn't even be exposed.

Do you think these places are generous with their water and all of it gets washed away?

Afterwards your car cannot dry easily since its the winter. Corrosion forms in the presence of moisture, salt accelerates it.

Even if you manage to rinse the salt off, how long will your car stay salt free?

I don't know, periodically washing the car in the winter to prevent corrosion just doesn't make sense to me.

It makes sense to oil spray it to lock the moisture away and leave it until spring.

Unless you’re in Alaska or somewhere that stays below freezing all winter there will be days where the roads will be wet and it’ll be warm out. Perfect conditions for rust to form. That’s when you want the salt off.

It wouldn’t make sense to wash on a daily basis but it does make sense to give the underbody a through rinse on that one nice day in the middle of winter. Caked on mud/silt/salt will only accelerate the rust more as it’ll retain moisture.
 
Does washing the car in the winter even help?

If you are running through an uncontrolled automatic wash you're dissolving the salt in the water and possibly forcing it into places that normally wouldn't even be exposed.

Do you think these places are generous with their water and all of it gets washed away?

Afterwards your car cannot dry easily since its the winter. Corrosion forms in the presence of moisture, salt accelerates it.

Even if you manage to rinse the salt off, how long will your car stay salt free?

I don't know, periodically washing the car in the winter to prevent corrosion just doesn't make sense to me.

It makes sense to oil spray it to lock the moisture away and leave it until spring.
Sand and clay particles (and any other solids) in the water can damage the paint on a vehicle, so they are allowed to settle and are removed. Seems to be a little misinformation on this thread . I also know for a fact there are proprietary filtration systems used.


Reverse osmosis (RO) systems use a pump to increase the pressure on the feed side of the equipment and forces the water across and through a semipermeable membrane. This process, results in approximately 96 to 99 percent of total dissolved solids (TDS) coming out of the carwash process. When applied and functioning correctly, RO equipment can effectively reduce levels of salt, hardness and silica minerals that contribute to carwash-related spotting.

If an automatic tunnel wash station utilizes this system to process wash water, the plant backwash water it creates can be sent back to the head of works and recycled for re-use. The reverse osmosis reject water being approximately 3 – 4 % of the total water used cannot be reused as this will cycle up the dissolved salts to the point that would cause the plant to fail, unfortunately this water must be sacrificed and sent to drain.
 
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Does washing the car in the winter even help?

If you are running through an uncontrolled automatic wash you're dissolving the salt in the water and possibly forcing it into places that normally wouldn't even be exposed.

Do you think these places are generous with their water and all of it gets washed away?

Afterwards your car cannot dry easily since its the winter. Corrosion forms in the presence of moisture, salt accelerates it.

Even if you manage to rinse the salt off, how long will your car stay salt free?

I don't know, periodically washing the car in the winter to prevent corrosion just doesn't make sense to me.

It makes sense to oil spray it to lock the moisture away and leave it until spring.

You can 100% tell who washes their car and who does not by how quickly it rusts here in Michigan. Most auto washes with an underbody sprayer that I've used allow you to drive over it nice and slow, really dousing the underside.
Then again, they use so much salt here that black cars will look nearly entirely white if you don't wash them. It's bad.

I'd definitely recommend a lanolin based spray if you really want the car to last.
 
With the recent supply chain stuff and the trend for OEM's to stop carrying parts past 10 years, what will be our situation with non rusted but obsolete 10 year old cars?

Buy a car that they make a lot of and is popular with the aftermarket. I bought a G35 because a lot of parts are interchangable with other Nissan/Infinitis. I'm also a person who's not afraid of modification though, so an engine swap if I have to is no big deal.
I should probably buy a couple sets of things like door seals and trim parts though.
 
When I lived on South Padre island we had a car wash situated right by the ferry that concentrated on cleaning the undercarriage. The locals that used it had cars that lasted rust free for years. The ones who didn’t use it had rusty cars that were only 3-4 years old.

I drive older cars (daily drivers) that are prone to rust due to poor or nonexistent factory rustproofing. I keep them rust free by spraying off the underside throughly at least twice a month.

My ‘02 Jaguar XKR, which is the newest old car I’ve owned in 40 years is known for rusting in the usual undercarriage areas. So far the only rusty area is the iron exhaust manifold, which already had some surface rust on it when I purchased the car 5+ years ago.

A regular regimen of rinsing off the car does wonders for rust prevention, even when the water purity isn’t the best.

Z

PS : A minor oil leak occasionally doesn’t hurt either ;)
 
Fluid film in all the nooks and crannies. Keep fresh paint underneath, rinse it off once a week or after every storm. 18 years old and gets driven in all conditions!
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Short of undercoating the entire bottom of the vehicle, there isn't much that can be done. Unless you can find a touchless car wash that uses clean water for every wash (and I doubt any exist), the undercarriage spray is just spraying the bottom of you vehicle with salt water. I don't really think that's doing it any good...
 
Short of undercoating the entire bottom of the vehicle, there isn't much that can be done. Unless you can find a touchless car wash that uses clean water for every wash (and I doubt any exist), the undercarriage spray is just spraying the bottom of you vehicle with salt water. I don't really think that's doing it any good...
Did you read my post above? And the links? Sometimes you got to read the whole thread......
 
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