Tackle any water crossing with confidence with these proven driving tips

Spend enough time on the tracks and you’re bound to be faced with a water crossing. Whether you want to be there or not, often your only way forward is to tackle it head on. Some 4WDers go in search for these sorts of challenges, while others will do everything they can to avoid them. Regardless, there will come a time where you need get across in order to get home.

So what is it that gets the blood pumping? Is it the unpredictability and degree of risk that comes with each crossing any deeper than a few inches? Or maybe it’s the sense of adventure because you’re trying it for the first time – who knows? What we do know for sure is that water crossings are an integral part of the 4WDing experience, and can be tackled safely using the right techniques.

That’s why this issue we’ve put together your go-to guide to setting up your 4WD for water crossings. Plus, we’ve packed it full of easy to understand driving tips to get you through even the gnarliest challenges. So strap on your floaties and get ready to tackle that next water crossing with confidence.

WATERPROOFING MADE EASY

Surprisingly, most 4WDs only have a recommended wading depth of around 50–70cm, which means fitting a snorkel and a set of diff, gearbox and transfer case breathers should be the first on the list. Just think that $10 spent on diff breathers could save thousands in repairs.

Your radiator fans also have a drastic effect on how your 4WD copes with a water crossing. As good as they are at passing large volumes of air through the radiator, they also work against you by flooding water into the engine bay. If your 4WD has electronic thermo fans, hooking them up to an in-dash switch means you can turn them off just before you enter the water. The other trick is to remove the drive belt if your fan is driven by the crank. Disabling the fan also prevents the blades from flexing and tearing into the radiator core or breaking off completely.

Last but not least is to pack a wading tarp or water bra. They take up next to no room in your 4WD, and they’re the best way to prevent water entering the engine bay. Whack it on just before you tackle the crossing (letting your diffs and drivetrain cool for a few minutes will also lessen the chance of sucking water in passed the seals too) and your chances of getting through are drastically increased.

PETROL ENGINES

Once you’ve got the basics covered, the first step for your petrol engine is to pop the dizzy cap off and give it a quick spray with water-dispersant spray, then run a small bead of silicone around the cap to seal it. You could also drill and tap a breather into the cap (clear of the rotor button) and plumb it into the air filter box.

Another option is to pressurise your dizzy using an air-horn compressor. These run at about 2psi and have enough flow to do the job.

It’s also worth removing the coil packs or spark plug leads and giving the spark plug a squirt with water-dispersant spray. When you’re done, also run a bead of silicone around the top sealing rubber on the coil pack or lead – this’ll prevent water getting down into the spark plug tube in the first place.

DIESEL ENGINES

Often overlooked, your fuel cap and tank breathers are another common point of water entry. As we know, diesel fuel contains additives needed to lubricate the injectors and pump. If water gets into the fuel and makes its way to these parts you’re almost always up for an expensive repair bill, and it’s for this reason installing a pre-filter and water separator is essential.

A pre-filter and water separator generally consist of a filter element and clear bowl with drain tap (so you can see if there are any problems early on). As water travels through the filter, it drops to the bottom and becomes visible through the bowl, and then in most cases it’s as simple as opening the tap.

12V PROTECTION

Regularly cleaning your engine bay and giving electrical connectors a thin coat of water-dispersant spray will go a long way to guarantee a reliable connection. If your 4WD’s seen a few adventures in its time, you may benefit from relocating some fundamental electrical components. Depending on how much room you have under your dash, moving your ECU from under the seat or kick panel to up under your dash, then running a new earthing strap, is often enough to get you out of trouble.

TAKING THE PLUNGE

The worst thing you can do is plough straight into a water crossing without checking it first. Even if you’ve driven the same track before, erosion, other 4WDs and flash flooding almost always guarantee it will have changed. Here’s how to tackle any crossing with confidence.

1 CHOOSING YOUR LINE

First off, you’ll need to walk the crossing so you can plan a safe path for your 4WD. Keep an eye out for sharp rocks, sticks or broken glass, and plot your course noting any holes, boulders or fast flow areas that may pose a risk. It can also help to take a few long sticks to mark out any obstacles like large boulders or drop-offs.

You’ll also need to check the water flow rate. If you have difficulties standing up and the water is above your knees, there’s a good chance the pressure of the flow on the side of the 4WD will be enough to push it downstream.

2 VEHICLE PREP

If you haven’t dropped your tyre pressures since leaving the bitumen, you’re best off doing so before heading in. Depending on the surface below, your best bet is to aim between 18-24psi as starting pressures. It’s also important to remember that the more air that remains in your tyres, the more buoyancy your 4WD has, and the greater the chance of it slipping off course.

Last but not least, if you’re at all unsure about whether you’ll get through, attach a Hercules snatch strap or unspool the Domin8r X winch cable so you can effect a fast recovery if it all goes south. And before you kick off, it’s worth slotting it into low-range if you’re not already.

3 WINDOWS UP OR DOWN?

Slowing water entry is key to getting through deep crossings, so as a basis, keep all doors shut and make sure your vents are on internal recirculation. There are two different theories when it comes to windows. By leaving them down you eliminate the risk of getting trapped in the vehicle, for example they’re electric and you lose power. The other one is that by having them up increases buoyancy and stops water flooding the vehicle. You decide which one applies more to you, just be aware of the risks whichever you choose.

4 THE ENTRY

Steep and muddy banks can leave you stuck in the water and unable to climb out, so doing any track building before setting off will ensure you don’t get caught out. Entering slowly is your best bet, and once you’re in, gently accelerate to establish a bow wave. If you can match your speed to the bow wave so your 4WD rides behind it, you’re much less likely to flood the engine bay with water.

5 WADING ACROSS

Once you’re in the water, try to avoid changing gears in a manual vehicle. You might get away with it every now and then, but if the bellhousing is in the water, you could get water between the flywheel and clutch and lose all drive. A good rule of thumb is to stay in low-range and stick to a speed that maintains a small bow wave in front of the vehicle. Too fast and it’ll rush over the bonnet, too slow and it’ll disappear altogether.

6 EXITING THE OTHER SIDE

Your best bet is to make your exit slow enough that as you leave the water, the vehicle drains any water it is carrying before you hit any difficult sections of the bank. If you can’t stop and need to hit it in one go, maintain smooth steady momentum and resist the urge to change gears. Once you are out, pull off to the side of the track and have a look around the vehicle for signs of water entry or damage.

7 WHAT TO DO IF YOU GET STUCK

If you start to lose traction during your crossing, gently pulsating the accelerator and swinging the steering wheel fairly rapidly from left to right about half a turn will help the tyres grab any extra traction that is available. If you come to a stop, try to pull the gearbox into neutral without using the clutch – if you must, keep any clutch application as quick as you can.

If you’re at immediate risk of sucking water into the air intake, shut down the engine straight away, but otherwise, keep the engine running to avoid water being sucked up the exhaust.

This is where being prepared for a recovery comes in handy. If your Hercules snatch strap is already connected you’ll often have your 4WD out before it fills with water. It goes without saying that there should only be one vehicle in the water at a time. It’s extremely embarrassing if your mate gets two-thirds of the way across and gets stuck, then calls you for help to drag his vehicle out, only to find that you’re stuck right there behind him.

TRACKSIDE TIP

If you don’t have an Thumper Air Compressor and you need to dry out an important component like your dizzy or airflow meter, a few short bursts from your spare tyre should do the trick!

8 DRYING OFF

Whether you’re driving the beach up at Fraser or crossing a river in the High Country, the last thing you want is to watch your 4WD fill up with water because you were too lazy to pull over and take a few careful steps, or you didn’t take the time to check the water before heading in.

Water crossings are a world of fun when the right precautions are taken. No matter how much experience you have, there’ll always be an element of risk, so take your time and think carefully before taking the plunge.

No matter how capable your 4WD is, some water crossings need to be avoided. Backing up and finding an alternative route is always better than sinking your truck. It’s also better to have at least one other 4WD with you, just in case.