First up, a warning – if there is one thing about four-wheel-driving never to get complacent about, it’s river crossings. You’re only ever as good as your next one. I can still hear the words of one grizzled high country station owner after he gave me the OK to drive on his land – “And don’t drown ya’ truck. I’m sick of grown men cryin’ on my doorstep at 2 o’clock in the morning”.
Water obstacles come in many types and sizes, from puddles with attitude to fast-flowing mountain rivers. With all of them, make sure you know what you are getting into before you get into it. Check the depth of the water and the nature of what lies beneath. Pools may have a soft, muddy bottom; with rivers and streams, rocks or holes are likely to be more of a problem.
Attaching a rope to the back of a 4WD before it gets driven into swift, deep water means it can be hauled back more quickly if the driver gets into trouble. Loop the rope around the spare wheel or similar so that it does not drag in the water.
In braided riverbeds, look for the rapids. You will usually find the shallowest crossing at their head. Choose your exit point before entering but be aware that the best crossing is likely to be an arc rather than a straight line from bank to bank. Beware trying to exit up a steep bank – there will often be a deep channel in front of it.
Select the right gear before you enter the water – this will usually be low first or second, depending on how firm or loose the bottom is – and if your vehicle has a manual transmission, avoid changing gear until you are on the other side. That’s because the action of pushing your foot on the clutch pedal can suck water into the transmission.
Of course, if you get stuck and can’t go forward then you will have to engage reverse and head back to dry land. Reassess the crossing before trying again.
Aim to keep a small bow wave moving ahead of you as you cross – this keeps the water away from the engine. Once through the water, test your brakes. Both disc and drum brakes lose efficiency when wet, although discs recover more quickly.
If you are camping for the night just after a river crossing, be sure to dry your brakes, particularly in winter. Otherwise you might find in the morning that water in the brakes has frozen overnight and your vehicle will not budge. Leave the handbrake off overnight also, for the same reason.
After wading through deep water full of mud, silt, peat, grass or weed, check that the radiator is not clogged. The contamination can bake dry if it is left and block the radiator, leading to overheating. Clean out as much as you can on the spot, and wash the rest out with a hose as soon as possible. Don’t use a high-pressure hose as this can damage the fins in the radiator.
After wading trips, check the oil in the differentials, gearbox and transfer case for signs of water contamination (the oil will look milky). If water did get in, you will need to change the oil as soon as possible.
