Clean and shiny: What a freshly rust protected frame looks like
If you drive a body-on-frame 4×4 (and hopefully you do) the problem of frame rust has probably cropped up at some point, especially if you actually use your vehicle off-road. I’m one of those who do, and many times I’ve glanced under my truck after an outing to see my frame covered in a horrible combination of mud, sand, branches, clay and small animal parts.
All that moisture and organic mulch sticks to the frame like glue, and is held in place by the globs of mud and muck that penetrate every hole, seam, and crevice. Even the spray-wash rarely removes it all, and I’m left wondering how long my poor frame will last.
But now I’ve discovered what I believe is a simple, effective, and cost-effective alternative to expensive frame treatments, one that (so far) keeps my frame in great condition and stops rust in its tracks. And it costs almost nothing.
Since frames are made of steel they will rust, and usually from the inside out. But what you may have noticed on older 4WDs is that the frame rarely rusts near the engine compartment. Many people think this is due to heat generated by the engine which keeps things drier and therefore less prone to rust.
Although this may be partly true, the rust-free condition of the frame near the engine compartment is primarily due to oil. Over their lifetime, most engines leak, sweat, or dribble varying amounts of oil, and most owners and mechanics spill regular amounts of oil on a regular basis.
Over the years, much of that oil usually ends up on the frame before ending up on the road, eventually spreading and coating much of the front of the frame. This constant coating of oil does the obvious: it protects the metal from rust by eliminating moisture and sealing out oxygen.
So after reading about several commercial trucking companies that spray their truck frames with oil every year, I decided to give it a try. I mixed three parts freshly drained diesel oil with one part kerosene and poured it into a used spray bottle.
I slid under my truck and sprayed every square centimeter of frame with the messy black mixture. I sprayed it into the pre-existing holes in the frame, I sprayed it onto the top of the frame, I sprayed it on anything rusty.
Over the next few weeks, I crossed creeks, drove along beaches and dusty roads, climbed up muddy hills and explored remote trails. I got momentarily stuck in a sandbar. I got temporarily stuck in a meter of snow. I got partially stuck in a waist-deep mud sink-hole. I got briefly stuck in a river.
I continued using the car as a daily driver and didn’t wash the frame once. After three weeks, I grabbed a torch (flashlight), donned some goggles, and slid back under the vehicle to inspect the condition of the frame. It looked almost as clean as it did when I first coated it.
The long-term rust test is still in progress, but I’m confident this will be extremely effective at preventing new rust and retard the growth of existing rust. It makes perfect sense: oil prevents oxidation and eliminates moisture. It is rust’s worst enemy.
And unlike frame treatments that require surface rust to be ground, scraped, or sandblasted off, this simple oil treatment coats everything, rust and all. It penetrates, preventing ‘new’ metal being exposed to oxygen and further reducing the risk of oxidation (apparently, most paints and rust treatments lock moisture in, accelerating the oxidation process).
Coating your vehicle’s frame with a mixture of used engine oil and kerosene (or spray-on lithium grease, which works even better but costs a little more) can extend the life of your frame and save you time and money. It might not be the coolest solution to the problem of frame rust, but for the average bloke in the average rig, it just might be the best.
Give it a try: you have nothing to loose but the rust.
