Krown vs Penetroil vs other competitors for rust proofing?

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7,930
Location
Hudson, NH
That's not been my experience at all. Here's one of my cars treated with RP-342 cosmoline.

20201224_144647.jpg


And My oil sprayed car

20201219_125416.jpg


Both cars were out in the pouring rain today. The cosmoline car rinsed itself clean from 12" of snow, sand, salt. The oil treated car keeps attracting more and more dirt like a sponge. So I'm not sure what's happening with his strut mount.
 
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JHZR2

Staff member
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46,293
Location
New Jersey
That's not been my experience at all. Here's one of my cars treated with RP-342 cosmoline.

View attachment 38144

And My oil sprayed car

View attachment 38146

Both cars were out in the pouring rain today. The cosmoline car rinsed itself clean from 12" of snow, sand, salt. The oil treated car keeps attracting more and more dirt like a sponge. So I'm not sure what's happening with his strut mount.
That oil spray pic is pretty bad. Not my experience. Was it chainsaw oil or something?

My issue with the cosmoline type products (in my case, using Amsoil HDMP) was that moisture could still diffuse, and then rust could still form. I never saw moisture pockets underneath, but some of these products can dry out after many years.

I’ve generally avoided wax coatings in spots that I can’t see or top them up. I like oil type sprays in doors and other spots where there are seams.
 
Messages
7,930
Location
Hudson, NH
The original owner was using NH Oil undercoating. I continued on with FF the past 2 years.

The literature and SDS of Amsoil hdmp does not reference cosmoline. So it's something else. Not the same as what I'm using which is a real cosmoline. There is no moisture issue. Nothing getting underneath. I know because you can see through it.

Here is a pic of the 06 Escalade jan 24 2016. Not good.

20160124_133601.jpg


Here is the Escalade Jan3 2021.

20210103_103515.jpg

Hard to believe it's the same truck. It would probably be off the road by now like most other gmt800 in my area. Still haven't done the brake lines.
 
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I recently picked up a 2006 mazda 3 hatchback, i also want to add that i live in canada. We have long winters here and "The city uses several products to manage the snow and ice, including a mixture of sand and salt, gravel, and magnesium chloride."


The car is in decent shape and not as bad as the other gen 1 mazda's that were in my price range. I want to keep the car for probably 2-3 years as long as no extremely large repairs. There is some light rust on the body just in some places but I don't mind too much, seems like the paint chipped off, and some light rusting in in the wheel well areas. I am looking to get the car professionally undercoated to protect against future rust/corrosion etc and was looking for recommendations. Also for the painted area's like wheel wells and where the paint is chipping off, or where there is already rust - I was thinking of repainting those areas with some touch up paint or something to cover the rust and maybe apply some product by myself every few months in those areas? thanks!

So in the city I live in, we dont have many places to get this type of work done since we are small.
There is a place that does Penetroil undercoating for $179 for my car, it seems to be a oil dripless spray type of thing, has to be reapplied yearly. This is just the undercoat quote, I don't want to spend more then this so I prefer to just get the undercoat done and do the painted places by myself etc

Outside of my city theres probably unlimited options like fluid film, corrosion free, krown etc
I called a krown dealer and seems like they can do the undercoat for $140 ish

So my question is:

1. if you were in my position which product would you get? even if its unlisted I can do some research and see what city has it. I am looking to just slowdown future rust/corrosion etc. in my case is it worth it to get krown done ? or is penetroil good enough since its local anyways? budget is no more then $200 would prefer a cheaper product if i have to have applied yearly like in the $100 range etc

2. which product do u recommend that i buy for myself which i can spray on the painted area's/places that the undercoating doesnt cover every few months or whatever


thanks!
I have tried both ( Krown/Corrosion Free ) and both are excellent products but I think only Corrosion Free offers a warranty for undercarriage for stuff like brake lines, fuel tanks ( and that’s important ). That said, personally, I would not go to any Canadian tire store to get Corrosion Free done. All Krown dealers do a great job that I have been too.

Try and avoid car washes that wash the undercarriage once you start getting it done so it will last longer ( I gave up ever washing any of my cars in the winter ) .
 
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