Spraying used oil

Airplane oil

I also did this with hydraulic oil in the fire extinguisher. I'd say my coating lasted about two years in rain and sunlight, but it was on equipment that wasn't moving.

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Rust developed on my unpainted bucket loader only where hydraulic oil leaks washed off the LPS-3.

--jsw

I was using the oil to prevent somewhat rusty equipment from getting more r usty. I wouldn't have noticed a minor rust stain, but it seemed to work and there was a dark, oily coating on the surface for a year or two. However, I also had some CorrosionX HD, which is designed for the purpose. I put som e of this on equipment outdoors in 2010. There is still a noticeable coatin g left today.

Oil does not drip, once applied.

OK, so everyone sprays their oil without ever any getting on the ground.

It never drips off on the road.

It never gets hit with dust which absorbs the oil and drops to the road.

And we all live happily ever after. Right.

Um, what were you just saying about "real world"?

The road is made of oil. That's where asphalt comes from.

Here in southern Norway, the roads are kept more or less continually wet with salt throughout the winter. Buying a used car that's been "rust proofed" with Tectyl, or some other such material, is a dangerous gamble. As often as not, you'll find that the metal is mostly rust behind the smooth looking surface. Hacking at the bottom panels of the body with a screwdriver to look for places where there's no original metal left is part of the mandated bi-yearly roadworthiness test.

I prefer older cars (my daily driver is a '98 Range Rover, and I also own a '66 Land Rover), and like many, many others around here, I swear by lanolin. It covers the entire underside of the car, including the insides of all frame elements and other channels, doors, fenders, etc. The stuff crawls deep into crevices and vertically up panels, and stops exising rust from spreading, and new rust from beginning. There's very little dripping, and lanolin is environmentally friendly. Before it became available over here, spraying used engine oil (and then going for a drive on a dusty dirt road to seal it in) was a common practice.

Here's how well it sticks: the left half of this car was sprayed with lanolin, the right half with a mineral oil (not used engine oil, but a mineral oil specifically made for this purpose) -- and the picture was taken after the car had then been in daily use for six months:

-tih

Seems they're getting less so, though. A neighbor of mine works at a garage that preps new GM cars for sale. The cars have come across the Atlantic by ship, and the first thing they have to do to them is remove the rust that has accumulated in the weak spots, especially along the welded seam at the bottom of the doors. Didn't used to be that way, he says -- and he suspects it's simply about the quality of the steel.

-tih

Well, the *quality* of the steel is vastly better than it used to be. It's no more vulnerable to rust -- and probably less so -- than the old stuff.

More likely he's running into something about their rust protection. Based on US experience, that's much better than it used to be, too.

It must be something specific about the weld seams. They're using continuous welds where they used a lot of spot welds in the past.

It's the quality of the assembly, sealing, and finish

GM door seams and edges rust - particularly on their lower end vehicles. This is not new, and they don't have to cross the Atlantic for them to rust. A good soaking with an oil product - the lanolin products are better than most but any oil will help - gives them a fighting chance.