Water Crossings – how to get them right

As a company that protects the lifestyle of the Offroad Touring Enthusiast, our insurance will cover you if you happen to drown your car while attempting a crossing, but with a water damage excess and contribution payable, not to mention the inconvenience, it is simply much easier to just get it right in the first place.

The University of New South Wales proved that a GU Nissan Patrol will float in less than 1m of water, and was at significant risk of being washed away at this depth, even by slow moving water

We’ve compiled a list of tips to help you avoid breaking your Rig.

Understand the situation

Before traversing a river crossing, stop and take the time to assess the situation.  You’ll want to know:

  • How fast the water is moving
  • How deep the water is
  • What’s on the bottom (any holes, submerged rocks / logs etc)
  • What the best route across is likely to be
  • How you will need to prepare your rig

We’d recommend walking the crossing first, taking sticks and marking any key obstacles or holes.  If you’re in the top end where there are crocodiles, this may not be possible though.

Your other option is to stop and use the opportunity to let the car cool down before the crossing while you have a break.  If you are lucky, someone who has previously crossed may come through, or someone else might attempt it and you could watch how they go (it might even save you from getting wet)

Consider other options

The truth is that if you get a water crossing wrong and water gets into your engine, it’s going to be expensive. Our experience has shown that generally a vehicle that has water ingress has a high likelihood of being deemed a total loss; engine rebuilds alone can cost twenty or thirty thousands dollars alone.

Once you’ve assessed the crossing in front of you, you should also ask yourself the following questions:

  • Do I need to do this crossing, or is there an alternate route?
  • Is this the safest place to cross?
  • Is the exit OK, and are there anchor points if I need to recover?
  • Am I confident that I’ll get through here OK?

If in doubt, we recommend that you don’t attempt the crossing. Could you afford to be without your car while it gets repaired? How would you get home right now if the worst were to happen?

 Prepare your vehicle

We’ve already mentioned that you should stop and let the vehicle cool, for two key reasons.  Hot brakes and cold water don’t go well, and, hot diffs and transfer cases don’t like cold water either because the fast cooling causes contraction, which can suck in water into them.

We’d always recommend that you fit a water crossing cover, even if you make one out of a tarp.  It will help create a bow wave and keep water away from your radiator fan, which can prevent it from being pushed into your radiator and causing a hole.

Have your winch or recovery straps ready and accessible in case you need to hook them up, and have a spot identified to recover from.  This is especially important in water where your vehicle will be over the wheels.

Understand the wading depth of your vehicle, and know that your raised air intake is most likely not fully sealed, meaning that you still run the risk of water ingress unless you seal it .

Consider raising the breather hoses on your diffs and drive gear to help prevent any contraction from sucking in water.

Turn off any non-essential electronics, and do your best to waterproof any places water may be able to get into them.

Tackling the crossing

Once you’ve prepared, it’s time to get in and drive the crossing.  The general recommendation here is low range, second gear.  You don’t want to go too fast, but you also want to maintain momentum and create a small bow wave.

You should be about a brisk walking pace, which is slow enough to react to anything unexpected.

If you get stuck, the number one rule is to stay calm and collected – many situations are made from an incorrect reaction – so visualise what you might do should the worst happen. Having a plan can be the difference between success and failure.  Ultimately, safety is the number one priority – if you’re unsure find another way around.

If you get hung up, carefully try to ease the rig back gently, and then try to drive around the rock or hole.

If the vehicle starts digging in and you are stuck, and if the water is anywhere close to the wading limit of the car, consider turning the engine off, grab the winch or recovery cable and start the process of dragging the vehicle out.

After Your Crossing

Once you’ve emerged from the water on the other side, stop if it is safe to do so, and let the excess water drain from the vehicle.  Many people disregard this concept, but if you do, you’ll drag water up the exit and track, making it muddier and more difficult for the next person.

Do a quick check for anything that may have got caught under the vehicle during the crossing, and then move off, slowly squeezing the brakes on and off to help dry them out and get them working properly again.

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Comments 17

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      Author
  1. One of the great things about a G60 patrol was that they didn’t float. Sure the cab filled with water but without any electronics who cares . You could hose it out (or just drive though a clean river) lol
    Everything in life is a trade off 😞

  2. Thanks Aiden some great info there, im off to the cape in 2020 so most relavent to me.

    A Question You mention if you get stuck in a water crossing to turn off the engine, I have heard that this will suck water up through the exhaust and into the engine which is a bad thing, I was always told to keep the engine running to stop this happening.

    Am I wrong in this assumption, or is it safe to turn off engine when the exhaust is ubder water ?

    thanks

    Chris

    1. Post
      Author

      Hi Chris,

      This is a difficult question to answer, and I’m not a mechanic. Water getting into your engine full stop is definitely bad, and there is a chance it could get up the exhaust when you turn the vehicle off. However, if you are close to the wading depth and have not sealed the intake or airbox properly, you risk water getting into the running engine through the air intake. Water doesn’t compress, so this will kill your engine. Water going up the exhaust could cause damage, but if the engine is off, it isn’t going to be as catastrophic as water in a running engine.

      So if you are confident that water can’t get into your engine via the intake because you’ve sealed it or your are not deep enough for that to be a risk, then I’d leave the engine running, but if you think it is too deep, I’d turn the engine off. I’ve heard a good way to test the seal is to put your hand over the air intake – if the air intake is sealed, the engine should stop. Be careful though as many ‘snorkels’ on the market are simply raised air intakes these days and not sealed…

      Anyone a mechanic here and want to back this up (or shoot me down)?

      Aiden

      1. I wouldn’t be putting my hand over a snorkel head while running. Especially with a 3+lt plus size diesel engine. They move a lot of with air. Chance are you could do damage to your hand.

  3. Why would you consider turning your engine off and risking water running back inside the exhaust, plus using “battery power only” with no charging to assist. You could be doing a solo trip then would really need your Club 4×4 policy!!

    1. Post
      Author

      Hi Louis,

      Thanks for the comment. I’d recommend turning the engine off if you think you are at the wading limit and there is risk of water entering the intake. If the engine is running and that happens, you’ll break the engine potentially. Sure, there is a risk turning the engine off but if you are at that depth, it is the lesser of two evils in my opinion. As for battery power only, I’m not sure I understand. I was talking about turning unnecessary electronics off, not disabling the alternator.

      I’m reaching out to some experts for a definitive view here on what to do because it is not clear and there are contrasting opinions…

  4. My instructions would be fit a water bra first even if you have a snorkel fitted as you can cross the water slightly faster and protect your fan and your engine from water ingress do not rely on your snorkel alone, in my 30 odd years of 4wdriving I have seen more damage done to the radiator by the fan being pulled forward by the water, Toyota states that there snorkel is for dust only to keep the intake higher in cleaner air. In my experience people try to drive to fast though the water therefore increasing the actual depth from half way up the wheels to causing it to go over the bonnet.

  5. I think Louis was making the point, a good one, that using the winch to retrieve without the engine on will very rapidly drain your battery.

    1. Post
      Author

      That is a good point Shannon. The recommendation to turn the engine off was only if you were worried about water getting into your intake – like if water goes over the bonnet. If the engine can breathe without water getting in, we’d recommend leaving it running.

  6. I remember crossing a river near The Dig Tree years ago. The river was flowing gently but the crossing was quite close to a slightly turbulent section of the river where water spilled over a natural rock ‘dam’ of just a few inches. I got a little too close to the turbulence and the car went quite deep. On the return journey I kept further away from the turbulence – the water was much shallower. Its obvious really. Turbulence is going to gouge out a deeper hole. Stay away from water thats spilling over any natural little ‘dams’ no matter how small they look. When the river was in flood it could have gouged out a much bigger hole that you cant see.

  7. I carry an old fashion Turfer winch that still works fine with an extended cable and from rescuing my old Range Rover in the 70s and 80s to being useful still on the trusty P38 well into the 20th century. No battery drain – but a bit more of a crock risk. I have been looking to fit a power winch, but think the comments above have talked me out of it.

  8. Back when I was 19 I had an old Austin A-40. I was in a torrential downpour going over about half wheel height water on a suburban road that happened to be just about a non piped in creek and as I crossed thinking it was trivial a torrent of water came down the river. It actually went up over the bonnet of the old car and my mate and I felt it start to float. I put the car in first and as the water was pushing to the driver’s side to take us off into the local creek, I pushed back from that side while he got out and started pushing at the rear. The car, even with bot doors open, was still floating at the front end due to an air pocket caused under the bonnet. We pushed and pushed and suddenly the drive wheels hit the ground and it started to drive itself off, no driver, out of the water. I got back in and steered it to safety.

    Had I turned the engine off, I would have lost the car and maybe been pushed into the creek by it. I have to say I wouldnt follow your turn it off recommendation. If you have a manual and your car allows it, even if the motor is stopped due to water, keep the key turned trying to start it again and be in first gear because, as I did with that same car at another time, it will walk itself off the road that way, while you steer, if you let it. Modern cars dont always allow a manual to be in gear and the key turned to start it of course but it certainly is worth a try if the engine fails and the only other choice is to rent it out as a houseboat!

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