How to Cross Rivers and Creeks

Water crossings require a different approach than any other form of off-road driving. With real potential to cause injury or worse and with a highly increased chance to damage your vehicle, crossing rivers and creeks should be approached with respect.

troop carrier crossing remote river
Planning

Most people are happy to ‘walk’ the crossing before driving through, checking the depth and feeling for dips and holes and establishing how much traction is on offer. This time also gives components like the differentials, gearbox and transfer case an opportunity to cool down. Dunking any hot metal straight into cold water is rarely a wise decision. The rapid cooling produced lowers the air pressure inside the diff and axles and encourages water to be drawn inside these components.

This time also allows an inspection of the 4WD and the chance to establish where the engine air intake is located. The air intake is a direct route for water to enter the engine. A 4WD fitted with a ‘snorkel’ enables the air intake to be lifted above the engine bay and out of harms way. If your vehicle isn’t fitted with a snorkel care must be taken to never submerge the air intake. Drawing water into the engine via the air intake will nearly certainly cause expensive, terminal damage. Your four wheel drive will most likely remain stuck in the water crossing until such time as recovery is completed.

Vulnerable Bits

An inspection of the radiator fan should be made with the engine turned off. If the fan ‘freewheels’ when turning it by hand then it is a viscous clutch unit and its generally ok to proceed. If the fan is a fixed unit meaning it turns full-time corresponding to engine revolutions the fan belt should be disconnected before crossing. It has the potential to bend and propel itself into the radiator.

This is a good time to spray under bonnet electrics with a liberal dose of CRC or similar water repellent especially in 4WD’s with petrol engines. Diesel engine vehicles aren’t installed with the more vulnerable electrical ignition systems that petrol comes supplied with.

A tarpaulin stretched across the nose of the car can aid in acting as a buffer, generating a bow wave in front of the vehicle and diverting water away from the engine bay.

Escape Route

Windows, especially electric, should be wound completely down and seat belts unfastened. This allows for an easy exit in the event of a mishap. If you have come to a stop in a water crossing it is often advisable to disembark via a window rather than open a door and allow water inside. Position valuables and your recovery equipment in a location that makes them easy to get to. No point having a recovery strap if its locked in a toolbox 2 feet under water.

4WD crossing large river

Because the ground isn’t visible we need to make a mental picture of our intended driving line based on what we learned from walking the crossing. Entering the crossing gently in low range 1 or 2 gives good responsive control over the four wheel drive and allows the car to generate a nice rolling bow wave. This bow wave, pushed by the correct momentum of the car helps to drive water away from the engine bay and can be maintained as long as momentum is kept up. Don’t change gears while traversing a water crossing. This will allow water to get between the clutch plates and flywheel and may affect the ability of the clutch to propel the car.

Rhythm & Control

Maintain a steady rhythm while keeping control over the vehicle. Big increases in acceleration only serve to shower the engine bay with water. Much like Driving on Rocks this type of blind driving is about feeling what is beneath the wheels and how they are responding. If the vehicle stalls disengage gears without using the clutch and try and start the engine. If it restarts then you have no real choice but use the clutch and try and drive out.

If the engine won’t start and regular recovery isn’t possible, then as a last resort, the vehicle may be able to be cranked out on the starter motor. Engage the gearbox with the clutch fully out and turn the ignition key. With enough battery power and a robust starter motor it is possible to move the car along in this manner. Not recommended but possible.

A good practise when exiting a river or creek is pull up on a slope and drain the water away. It’s also a good time to evaluate your braking capability after the drenching. Post river crossing inspections should include a check on differential, gearbox and transfer case oils for water contamination.

When making any type of water crossing to is prudent to remember that rainfall can make yesterdays knee-deep creek into today’s raging river.

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