The dangers of dust ingress…
Believe in global warming or not, there’s no arguing we’re seeing a lot more areas in drought. Combine that with our love of touring the outback of this magic country and, all of a sudden, we’re starting to see more than a few engines impacted by dust ingress.
There are a few four-wheel drive manufacturers that have had hassles with air boxes not sealing the way they should but, regardless of this, there are several ways that you can minimise any dust getting into the heart of your rig.
Let’s have a look at a few of the issues and solutions you can undertake to help keep you rolling.
Why does dust cause damage?
Beyond just the idea of ‘dust is bad’, we thought we should kick this yarn off with exactly what happens if dust gets into your engine.
As most will know, air is drawn into an engine by the vacuum of a piston heading south in the block or being forced into the cylinder by way of a turbocharger. The tolerances of the pistons and rings against the cylinder walls are minute. Same too for the blades of the turbocharger spinning upwards of 130,000 revolutions per minute.
For engines to work efficiently, components inside move within tight tolerances. If there’s dust ingress via the engine’s air intake, instead of smoothly lubricated components moving against each other, this dust (and sand and dirt) will rub on things it shouldn’t.
It can take just a single dust, sand or dirt particle to score a bore in the engine block, and suddenly it won’t seal as well as it did.
This will then cause other problems, such lower compression in the engine and the possibility of the rings grabbing, and foreign particles being pushed around the engine, none of which is good for the heart of your beloved 4×4.
This is where air filters come in. Air filters are designed to capture any foreign particles that are sucked into the air intake and allow only clean air to pass into the engine itself. Sounds good, right? The problem is there have been some design issues with some vehicles recently where foreign particles have made their way past the air filter and have been sucked into the engine, resulting in the failure of other engine components.
One of the bigger names with dust ingress issues recently is Toyota.
And then, there are the Yotas…
Don’t get me wrong, this isn’t a shot at Toyota; I’ve got an old 80 Series LandCruiser and an N80 HiLux in the driveway now, and I love them both dearly. But something that has caused a lot of concern in the four-wheel driving world is the ongoing issue with dust getting past air filters on new Toyotas. Specifically, the HiLux model has gone from the old round style air-filter to a panel filter.
Those with older four-wheel drives will remember the cylinder-style air filter, made from steel and a filter element, and you could tighten the air-box lid down hard onto the rubber seal on the top of the filter. In the interests of saving costs both at manufacturing and during services, many manufacturers have opted to go to a panel-style filter as found in many passenger cars. These are cheaper and easier to change, but they lack the sealing qualities of the old round filters. Additionally, there is more surface area to clamp down on and any if there’s any slight deformity in the rubber surround of the filter, there’s a good chance dust will get past it.
This was is what happened when we took a couple of HiLuxes into the desert to road test them, and two of them went into limp mode. It turned out the MAF (Mass Air Flow) sensor got coated in dust so it couldn’t read the pressures correctly. After a chat with Toyota we were told to remove the sensor (on the engine side of the air filter) and blow it out with compressed air. Sure enough, this worked… at least for a while, until it did it again a couple hundred kilometres down the road.
Toyota’s fix for this issue was to add ‘blowing dust out of the MAF sensor’ to the scheduled servicing book. Toyota is still ‘looking at having the filter system fixed’ at time of writing, however, and has also stated that dust of the size getting past the air filter ‘won’t cause adverse issues within the engine’. Time will tell. So far, my ‘Lux has been good; but then, I’m pretty pedantic about keeping out of the dust.
Ways to minimise dust ingress
There are a few ways to help minimise dust ingress into your four-wheel drive, and save your engine from being dusted.
First off the bat is the easiest one; don’t travel too close in convoy on dirt. You’d be surprised how often you’ll see folks in convoy on dusty roads sitting right behind the 4X4 in front. Ease off a little and give them some room, because even aside from the dust issues, it’s a lot safer because you can see more of the road ahead and what’s coming up, whether it be washouts, floodways or the odd water buffalo.
The next step is to fit a snorkel, and maybe even a pre-filter. The snorkel raises the air intake and if there’s a decent crosswind, it will assist in only clean air getting into your intake. Take this up a notch and you can run a pre-filter over your snorkel head. Unifilter makes a bunch of options for standard ram-heads, and also four-inch covers for those who have stainless steel snorkels. Aside from filtering out the bigger stuff, pre-filters will also catch a fair whack of the smaller dust before it even gets to your air box. Just remember to clean it out after every trip and don’t run it permanently.
Lastly, only ever use quality air filters. The moulding of the rubber skirt is just as crucial as the filter element itself. Get a cheap ‘eBay’ special and chances are the filter won’t fully seal in the air box, not to mention the filter elements are generally junk and will let large particles through.