Oil Undercoat your car!

[4cefed]

Those of you living in places like Arizona, California, Gobi desert, etc. probably don't need to read any further. I've been trying to get my vehicles undercoated for years but I can never find "the guy" that still does it. (Damn EPA.) So I did it myself finally. Since my bodywork skillz are teh fail, I thought I would do something constructive with my paint gun. I have one of the newer HVLP (High Volume Low Pressure) guns that is supposed to use more air volume and deliver a better finish. So I built this:



I unscrewed the paint cup and found that an airline quick connector screws in it's place. I used a funnel and rigged up some tubing to route the oil to the gun. I had to separate the regulator from the gun to gain mobility. I don't have a lift so I had to jack up one side of the car at a time, I gained a lot of dexterity by moving the regulator/air filter. I used a short piece of airline to connect the regulator to the gun.

I set the pressure to about 50-60 psi. That seemed to work well for the oil I was using. I had a friend hold the hopper and add oil. The gun design sucks the oil out of the hopper so there is no need to try to force it in there. Holding the hopper a few feet above the gun works just fine.

The results are amazing. Only a little oil at a time comes out and it's super controllable. I only had a few drips where I laid it on thick in a few rusty spots. I was worried there would be oil all over my driveway but it only dripped in one or two spots. If you had a paved driveway or a concrete floor you could probably get away with putting down a bit of cardboard to collect any runoff. In total I used a little more than a half quart for the whole car.

My great uncle used to do this for his customers, apparently he would use a punch to put a hole in the top of the rocker (the door sill) and fill that with oil. He would also punch a hole in the side of the bottom of the doors and fill them. The rockers on my neon, truck, and 240 don't exist anymore so I skipped this step. He would plug the holes with a plastic or rubber plug.

I used straight used Mobil 1 10-30 that was near black. Adding ATF to the mix will help a lot, it acts as a penetrant and seeps into places. The last step is to blast down a few dirt roads to add a coating of dust to the oil and hold it in place.

[Jesda]

Nice setup! Seems cheaper to use old motor oil rather than fresh Mobil 1, no?

Ziebart is the only place I've seen that advertises this kind of service, and they use some kind of "coating" but I'm not sure what it is.

[bcar240]

Is this is even remotely similar to the effect I got when my front main seal went then I would recommend this route. Nothing from the bumper to halfway back on the underbody had a lick of rust after that. I have been thinking about undercoating for a while, but it's always the same with "that guy," reading about people taking cars to some mythical shop that does undercoating.

[snwbrdr435]

It works, not sure how legal it is to be spraying oil on the bottom of your car or truck.

[4cefed]

Nice setup! Seems cheaper to use old motor oil rather than fresh Mobil 1, no?

It was used oil. I guess I didn't word it too well. It was "fresh" in the sense it just came out of the engine the day before. I'll probably recoat the car again in another month when the snow tires go on. After that it should be once a season.

[Looneybomber]

Is this a joke? Apparently I've been living under a rock for all of my life because I have never heard of this.

[4cefed]

Sadly it's not a joke. It works very well when done correctly. I've had a few cars over the years that had a leaking oil seal or transmission, not a spot of rust on the bottom.

My 240 came from Virginia originally and was in great shape when I got it. Two years later the rockers have rotted out and the frame is in danger. It sucks up here.

And snwbrdr435, i'm pretty much positive it's not legal, that's why I can't find anyone that will do it anymore.

[Looneybomber]

And snwbrdr435, i'm pretty much positive it's not legal, that's why I can't find anyone that will do it anymore.

Can't be any worse than using old oil as weed killer in the driveway.

[AZ89two4Tsx]

Is it flammable at all?

I'm puzzled by this.

[Razi]

Is it flammable at all?

I'm puzzled by this.

Engine oil?

[AZ89two4Tsx]

Yeah, nevermind. I'm pretty dumb right now

[4cefed]

Is it flammable at all?

I'm puzzled by this.

Well ya, but the flash point for oil is pretty damn high. Mind the exhaust system when you spray. Just to be sure there were no problems, I let my car run for about a half hour with an extinguisher on stand-by. You could dump oil on a hot exhaust all day and it won't catch fire.

However, if you car catches on fire from some other reason, the oil on stuff won't help.

[Jesda]

You wont see a fire unless something specifically ignites it.

[PBfrEAk]

I can 1st hand tell you that not only does this work amazingly but it's been done for as long as my grandfather has been alive anyway.

My dad and I just recently pulled a 440 out of my grandfathers old dodge pickup he was taking to the scrap yard. It has been sitting since 1985 in a small clearing behind his garage. The motor is out of a '69 Charger that was my dad and uncles "field car. (I won't go to far into that for the sake of getting of topic but how ****ed is it that using a charger as a field car was just fine when they were kids???!?!)

Anyway, while working on getting the motor pulled out I noticed that the inner fenders (among other things) were covered in what seemed to me was motor oil (which of course had a ton of debris stuck to it). I asked my dad if this motor had an oil leak or if the old motor that was in it before did, and why my grandfather never cleaned it up. Then he wiped some of the oil away.

I was shocked at how clean the metal was underneath and upon further inspection, anywhere that oil was, that truck was as solid as a rock. Other places weren't so lucky and thats why the truck was getting scrapped.

So to make my point. Oil works GREAT and is CHEAP considering you get new stuff everytime you change your oil.

Now I will say in PA there are plenty of places that do undercoating and it does do a much MUCH better job and is well worth the cash, oil is a very acceptable substitute especially when you compare it to doing nothing at all.

TL;DR: Grandfather used oil on 1970's truck; Sat for 20 plus years. Still looked new under oil treatment. +1 for doing it!!

[Looneybomber]

Will this work if the undercarriage is already rusting some? I ask because I typically just use old motor oil as weed killer.

Side note: having a grimy undercarriage would drive me nuts every time I got underneath to change oil or whatever.

[KoopaTroopa]

thoughts on spraying it down with wd-40? I had to use it to spray into the door frame last winter when it rained/froze solid. There was definitely still a layer of wd40 and dirt sticking to the sides of the car below the door for at least a month or two.

[4cefed]

Will this work if the undercarriage is already rusting some? I ask because I typically just use old motor oil as weed killer.

Side note: having a grimy undercarriage would drive me nuts every time I got underneath to change oil or whatever.

Absolutely. It will soak into the rust and prevent it from rusting more. On my car about half of the underside was coated with some kind of factory bedliner stuff that looked pretty solid, I only sprayed the painted metal and the rusty stuff. I would rather deal with washing my hands than watching the frame dissolve.

Koopa- The "WD" in WD-40 stands for Water Displacement. It was formulated to protect things from moisture. I've coated engine blocks I've gotten back from a machine shop that I didn't plan on using right away. It will work well for a short time. The oil is so light it will actually evaporate away slowly. A few months after storing one block I found light rust on a few things already.

When I was undercoating I used some thicker looking Liquid Wrench stuff in a few tight places where I needed the straw to get into something. It will work well if there is only a few places of concern that you don't mind spraying every couple of months depending on conditions.

[bang4dabuck]

I think I heard of using deisel fuel as well as kerosene (I think) also. I heard they do this up north every winter.

Yow might be able to get away with a garden sprayer.

[4cefed]

Yow might be able to get away with a garden sprayer.

Negative.

I tried this first because I was lazy. There wasn't enough pressure to push the oil through the tube even with the spray nozzle removed. I was able to squirt ATF out of a spray bottle though. Much lower viscosity.