Rust Proofing Your Prelude

[spiffyguido]

For those of us in colder climates with salty roads (like me), rust can be a serious problem. Here's what to do to prevent rust:

Go to your local tool store and buy an undercoating gun. Trust me, it will be the best 40 bucks you ever spend. If you don't have an air compressor, a large pump-action weed sprayer will work in a pinch.

Find a time where you don't need your car for at least 24 hours. Take the bus if you have to, things will work out better if you allow some drying time.

To start, change your car's oil, and save the used oil that comes out. Remove all of your fender gaurds, splash guards, wheels, mudflaps, etc to expose all the panel edges. To go the extra mile, you can also remove those plugs in your door jam that lead to the inside of your body panels.
Take some old newspaper and masking tape and mask off any places that might get overspray. It doesn't take much. I usually just protect the bottom of the doors and around the bumpers.

Fill your undercoating gun (or weed sprayer) with your used engine oil. Throw on some goggles, lay under your car, and go to town. Soaking the panel-crimp points, fender wells, and insides of the panels with oil will prevent moisture from being able to contact the metal. If you find the oil too thick to spray, mix it with diesel fuel (not gasoline). Don't worry, diesel evaporates very quickly and it makes your garage smell delicious.

Once you're done with the oil, let the car sit for about an hour. The oil will drip and spread from the points you sprayed. Allow time for this to happen, the deeper it penetrates, the better.

Now you need to seal it. Buy some vehicle undercoating fluid. I'm not talking about the kind that comes in an aerosol can, I mean the kind that comes in a bucket. It'll have the consitency of shampoo, and you can get it many places. Put this fluid into your spraying device, and coat all the same places you coated with oil. The undercoating will form a hard waxy layer over the oil, keeping it clean. Let this dry for about a day, then put your car together and live happily ever after.

I have found this technique to work exceptionally well. I have a winter driven 1991 lude...absolutely no rust...and I don't wash it every day. It will only work properly if you use both the oil and the undercoating together, with the oil going on first. Here's why: The oil protects the panels from being in contact with moisture (which, as we know, promotes oxidation). Oil on it's own however has a bad habit of collecting dust and dirt from the road, which in turn absorbs the oil off your panels, and then as you wash the dirt away, you're left with a bare panel after a number of months.

My solution to this was to then cover the oil in the undercoating. The undercoating is quite hard, it doesn't collect dirt, so it is excelent for sealing the oil onto the panels. The reason I don't use undercoating on its own is that it can crack with age, and creates tiny places for water to collect...not a good thing. Use both, and you're golden. If you plan on doing this before every winter, it should be good for a year. It's not a lot of work, it doesn't cost much, and it will save your lude from rusting in the first place, or prevent it from rusting further.

[RedRacer]

Very good post ! Excellent methodology and should work very well. I'm glad I don't have to deal with rust on this level. While I hate summers in the tropics, I sure don't mind not having to deal with corrosives from cold climate areas.