Automotive

rustproofing undercarriage

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  • Jan 16th, 2022 6:17 pm
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[OP]
Member
May 2, 2014
466 posts
181 upvotes

rustproofing undercarriage

i just bought a used car and would like to confirm if i will be doing rustproofing correctly....

based on previous posts here, it seems that i should go to a coin wash station, shoot some water in the wheel wells and underbody to remove debris, let it dry, and then go to Krown rustproofing? and i should be doing krown rust proofing every spring, as it is the warmer seasons when the rusting process is most active?

btw, where i live (near sudbury), we mostly use sand and i park outdoors
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Deal Expert
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Feb 8, 2014
26067 posts
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Socially Distanced
Use Corrosion Free, it doesn't drip and causes less rubber stretch. Washing is a good idea but get the spray done in November as you want to keep salt away from metal. The rusting process is slower in winter but you get above freezing days plus putting oil on after the salt has hit metal is not as helpful as preventing contact in the first place.

Also i have found Canadian Tire is not the best place for Corrosion Free, independent places or NAPA garages seem to do a better job. Its about the product plus its application, if they miss spots or just mist it then those spots don't get protected.

Oil spray is about preventing salt meeting metal which vastly accelerates corrosion. This happens due to rock chips or seams that didn't get fully painted or paint application defects when the car was built.

Krown drips when you get home and drips like crazy in spring. Also it stretches rubber. The result is very ugly.
In fact in Rand McNally they wear hats on their feet and hamburgers eat people
Deal Guru
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Mar 13, 2004
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Ontario
Washing the under carriage is a good idea if possible but not required. I have heard the same thing about doing krown in the spring time as thats when most of the rust starts since the weather is warmer thats when the chemical reaction happens between salt/water/metal.

That being said I do mine in Nov/Dec depending on how warm/cold it is. I also buy an extra can or two of Krown rust proofing and in the middle of the winter I will hit as many places as possible again to give it a fresh coat of protection.,
Penalty Box
Jun 26, 2009
5142 posts
4878 upvotes
GTA
The car is used, the damage is already done. You can slow it down, but you can't stop it.
Newbie
May 30, 2018
19 posts
17 upvotes
ausername wrote: i just bought a used car and would like to confirm if i will be doing rustproofing correctly....

based on previous posts here, it seems that i should go to a coin wash station, shoot some water in the wheel wells and underbody to remove debris, let it dry, and then go to Krown rustproofing? and i should be doing krown rust proofing every spring, as it is the warmer seasons when the rusting process is most active?

btw, where i live (near sudbury), we mostly use sand and i park outdoors
"Corrosion Free" is not only safer for rubber, but also rejuvenates it because it's silicone-based. The Canadian armed forces found it to be the best one.

Just Buy "Corrosion Free 3000" from Canadian Tire, and a long straw (cut it to 3 different lengths) from amazon, and do it yourself (learn on Youtube).

Liks:

Study by the Canadian armed forces:
https://corrosionfree.com/wp-content/up ... t-copy.pdf

Corrosion Free 300:
https://www.canadiantire.ca/en/pdp/rust ... ent=341376

Straw/Applicator (cut the 50" to 20"+15"+10"+5"):
https://www.amazon.ca/gp/product/B01ARB ... UTF8&psc=1

How to (It's for a truck...But same principle):
rustproofing-2489298/2/#p35582188
Deal Addict
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Feb 9, 2013
1961 posts
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Ottawa
Krown is a waste of money. The product is as thin as WD40. I got my car done in September and by November all traces of the product were gone just from driving during a few days of rain.
Deal Addict
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Nov 15, 2009
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One guy on youtube who does this kind of job said, he never washes underneath the car. He just scrapes all the rust off with wire-brush and cleans it with cloth (maybe air compressor) then coat it. I don't know if this is right or wrong but I can see his point of view. The water would cause more rust.

This fall I just did use spray can RustCheck Red can with spray handle I brought from amazon, with these two can I was able to do engine bay, trunk and door frame. I did use damp cloth to wash off dirt prior to spray. I still have to do the undercarriage. At Princess Auto RustCheck Green can (for undercarridge) sell out pretty fast during winter season. I assume this is good brand, next season I'll try it out.

I did underneath my engine bay with Tremclad Black paint. ( a small can $10 plus a paint brush). Holds up pretty good for 2 years or so. I did use emery cloth (sandpaper) to remove sum rust prior to painting.
Deal Guru
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Mar 13, 2004
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Ontario
Either the place you went to did not do it properly OR you just did not see the oil or it may be under the dirt and such since dirt will stick to it. I got my car done with Krown the first week of Sept, yesterday I was at my mechanic doing some things and while looking under my car I could still see the krown oil on all the parts.

Been going to krown with the car since new for about 5 years now, Its not a waste of money at all I have little to not rust on it and when my mechanic works on the car he loves it because every bolt comes out no problem where other cars everything is rusted and he needs to use heat to remove.
iflyplanes wrote: Krown is a waste of money. The product is as thin as WD40. I got my car done in September and by November all traces of the product were gone just from driving during a few days of rain.
Deal Expert
Mar 23, 2004
33251 posts
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MasterMK wrote: One guy on youtube who does this kind of job said, he never washes underneath the car. He just scrapes all the rust off with wire-brush and cleans it with cloth (maybe air compressor) then coat it. I don't know if this is right or wrong but I can see his point of view. The water would cause more rust.
Uh yeah but how are you going to avoid the road/environmental water when the roads are wet? You can't. And if you didn't drive the car in the winter (where salt wouldn't get on it, for example) you probably wouldn't need to rustproof in the first place lol. So yeah maybe "the water would cause more rust" but if you're never wetting the bottom of the car by never driving in wet conditions, you probably wouldn't ever have rust to "scrape off with a wire brush" and also not even need to bother coating anything.

I don't understand this thinking at all. Surely flushing things with an abundance of clean water, is better than never washing the underside yet still letting dirty road water (and dirty salt water in winter) hit it and just leave that there. I mean it's not like more water isn't going to come later--again unless you never drive in wet conditions.
Deal Addict
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Nov 2, 2008
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sickcars wrote: Either the place you went to did not do it properly OR you just did not see the oil or it may be under the dirt and such since dirt will stick to it. I got my car done with Krown the first week of Sept, yesterday I was at my mechanic doing some things and while looking under my car I could still see the krown oil on all the parts.

Been going to krown with the car since new for about 5 years now, Its not a waste of money at all I have little to not rust on it and when my mechanic works on the car he loves it because every bolt comes out no problem where other cars everything is rusted and he needs to use heat to remove.
Same here. My car is COVERED, and more so after yearly applications since 2015.

There was one year where it was thin, I think they were trying a new formula or something... as it dried out within a few weeks - I went back, asked the owner & he did re-spray.
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Mar 5, 2006
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Murica
I wash under carriage with a house and a lawn sprinkler. I move it each section and set there for 5 mins each. Sure it uses a lot of water. But I use fluid film so can use any pressure
Deal Fanatic
Oct 18, 2004
5221 posts
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Wat
sickcars wrote:
Been going to krown with the car since new for about 5 years now, Its not a waste of money at all I have little to not rust on it and when my mechanic works on the car he loves it because every bolt comes out no problem where other cars everything is rusted and he needs to use heat to remove.
My 13 yr old car is krowned yearly and looks brand new.
I found a new mechanic who checked over my car was and is extremely impressed with the car's condition.

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