Underbody rust proofing

stockhausen

stockhausen

stockhausen

Capodecina
Soldato
Joined
30 Jul 2006
Posts
12,130
Is it the view of this forum that the underbody rust proofing of modern cars is satisfactory or are there additional treatments that are available and worthwhile to combat the depredation that one suffers as a result of the salt that some councils spread on the roads after a heavy frost or fall of snow?
 
Depends really. By modern car, do you mean 2001 onwards or even newer?

If you're buying a 90's car, I'd probably want to get it looked at if it's not rotten through already. In a modern car, if you're not expecting to keep it till it's 10 years old... there's probably no point IMO.

If it's an import of an old car from a country that doesn't have a rust inducing climate, yes it's probably advisable.
 
Dup said:
Depends really. By modern car, do you mean 2001 onwards or even newer? ...
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In this particular context, I mean a brand new car, straight off the showroom floor. A neighbour's car has failed its MOT (basically because the Science Museum wants a demonstration of the damage that rust can cause to metal :D) and he wants to buy something new but doesn't want it to rust again - ever!

... In a modern car, if you're not expecting to keep it till it's 10 years old... there's probably no point IMO. ...
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That's the point, he wants to be able to keep it for ever and when he dies, to pass it on to his grandchildren.

I remember talking to my parents about rust prevention on cars and they said that back in the day, they used to take their car to a garage every spring, get it steam cleaned and have something sprayed onto the bottom of the chassis. I have never heard of this practice from anyone else and can't quite see why it would need to be repeated annually?
 
I never had any trouble with my old'uns and they just undersealed and waxoyled. Just used to pressure wash them when they'd been driven in gritted conditions (every week or so).

Seemed to work just fine...
 
I give my arches and underside a thorough clean every year, then apply some clear Waxoyl. Doesn't look pretty but definitely holds the corrosion back. :)
 
Lashout_UK said:
I never had any trouble with my old'uns and they just undersealed and waxoyled. Just used to pressure wash them when they'd been driven in gritted conditions (every week or so).

Seemed to work just fine...
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Did you rely on the manufacturer's undersealing?

Did you apply the Waxoyl yourself? If so, did you drill holes to get inside any panels / members and wouldn't this impact on the warranty?
 
I doubt any of it was factory, when I say old I'm talking 30+, although some of them were factory undersealed. Never done it myself, well, a few times in areas but not an entire underside. Just applied by brush or spray/injection depending on job.

I don't think drilling a hole in a panel and injecting waxoyl, then putting a small body-coloured plug in would be noticed, or invalidate a warranty.

Why not ask your dealer? I'd be very suprised if you have any issues though, unless the thing's built from tinfoil. Our Cherokee was new 7 years ago and the underside's still really clean, even though it's barely ever washed - and it gets used a lot in winter.

The new stuff they use on the roads is pretty aggressive though.
 
The proper waxoyl gun comes with a long pipe attachment you can use to thread into members etc. and spray the stuff inside. I find they clog up after a couple of uses - they're a rip off for what they are.

Instead, I just use plant spray bottles you can get from wilkinsons - just over a quid each IIRC. Drop the waxoyl into the bottle with a funnel, dilute it down with white spirit so it's thin enough to spray, then spray away. If you adjust the nozzle, you should be able to spray it directly into members if they already have holes in. The clear stuff looks like this:

vts18.jpg


Was freshly applied there, after half a day or so it dries to a hazy coating. Not even my pressure wash will shift once it's dried on... takes degreaser and a lot of elbow grease.
 
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Westyfield2 said:
Hmm, think I might do my VTR this winter. Original owner kept it garaged so this is it's first winter outside!
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Definitely worth doing like. Drop the spare wheel down and do as much of the boot floor as you can - they are notorious for rusting there! Chassis legs too. :)
 
Problem with the method above is you can only really get to open areas, not box sections, for that you need a proper gun & probe.

Wonder if you could adapt one of the garden pressure sprayers to work.
 
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