Wading depth; a guide please

The top of the wheel is a good indicator, Landcruiser and Patrol are 700mm. A smaller 4x4 will be less than that. Extra lift will increase your wading depth a little. A snorkel is best in case you drop into a hole, 100mm extra drop maybe the difference in drowning your engine, Michael

You can add things like does the vehicle have breather tubes on the gearbox and diffs etc? When a hot diff or gearbox hits the water they get cooled down and can suck water in past seals etc. So you need a breathing tube up high somewhere to allow the gear box and diffs breath. Mounting of alternator and or other electrical components unsealed?.

The question, which is a reasonable one to ask, if looking for general guidance, reminds of an old flying joke – but it does have relevance to the answer.

Pilot rings the station owner and asks “will I be able to get my aircraft into your bush strip?

“Sure” the Cocky says…

The pilot duly lands and overruns the strip and ends up in the trees, the aircraft damaged and the pilot’s pride bruise.

Irate, he says to the Cocky “you said I’d be able to get it into your bush strip”…

To which the Cocky duly replies “yeah, but you never asked if the runway would be long enough!”

So on wading depth; possibly the answer is very specific to what you are driving and the water course you are crossing…

Cheers, Baz – The Landy

Your door and body seals are the crucial area involving wading depth. Nothing worse than watching water pour in through badly-fitting seals, drain holes, or air outlet valves that don't seal properly.

The trend in recent years is to install larger drain holes in doors. With larger drain holes comes the ability for deep water to invade the cabin area and soak your floor mats and underfelt.

With many vehicles having poor corrosion protection on the floor panels, that's a recipe for rusted out floor pans within a very short time. Japanese vehicles are particularly bad for this.

The older Hiluxes had a double overlapping panel in the floor pans, and this was a prime area for floor corrosion.

That was what I liked about my old '77 F100 4x4! A galvanised floor pan!

600mm is good general limit for many vehicles. The Amarok recommendation is 500mm. Most of the Toyotas are 700mm, the Ranger is reputed to be 800mm - but I wouldn't like to try it out for regular dunkings at that depth.

Been with the brother when he crossed a fast-flowing creek in his old bog-standard turbo-diesel HJ61 Landcruiser wagon - and the water was lapping the bottom of the windows!
I was getting pretty worried for a while, but the old Cruiser never batted an eyelid and just plowed on through.

Maybe you need to take along an old Suzy! This one puts on a command performance!

Cheers, Ron.

Thanks so far:

What electrics are vulnerable and how can they be protected?
WD40 will do connectors etc but does the alternator or starter need treatment?
Do I need to find all the computers and protect them?

Re door drains & seals, yes, I was planning to tape up the drains and someone has suggested silicone? on the door seals.

BTW love the Suzi!

There are a lot of vehicle engines destroyed by owners and drivers hitting the water at speed. The wading depth stated for a vehicle maybe 600mm but an engine can be destroyed easily in only 300mm by to much right foot.

Wading depth is at walking pace.

Front wheel bearings are the first big risk. They are difficult to seal 100%, especially if you enter the water when they are warm.

I have crossed the Pentercost many times. I have never seen it deeper than 300mm. It can back up a little with the tide.
In 2008 there was talk of concreting it. I hope they never do.

Cheers,
Peter
OKA196 Motorhome.

Make sure you haven't been on the brakes a lot before hand some are prone to buckling. Electronics these days are the biggest concern cd stackers under the seat etc height at which computers are placed alternators are also nearly always forgotten about, your fan operating while submerged can cause big problems and some may hit the radiator cooling fins Definitely a good idea using a bling if in any doubt quite often people think it's too much of a hassle till it's too late, if you're able to keep up momentum you can drive through very deep water safely. Keep a snatch strap on hand attached to the vehicle so recovery times are reduced.
Have you got much experience doing water crossing if not get some practice in if you can in your local area with some friends it will boost your confidence and it will help you make the correct decision because you'll have a better idea of your 4WD's capabilities. Also you won't be unnecessarily stressing about what you may encounter on your trip.

The safety of crossing deeper waters also depends on speed of flow. You may chug through deeper still waters, whereas a fast flow will have your car off the crossing. As Peter and Margaret said, the Pentecost is normally a shallow crossing, wide but shallow. Other rivers such as the Durack will likely be deeper.

I believe BruceK is referring to his vehicle which is a Citroën 2wd? In which case I wouldn't go deeper than tyre rim depth.
He is planning a trip gathering around Australia May next year with a nomination fee of around $100
Plus your own costs.
He might be lucky with a dry northern summer at low tide
Cheers

.
What may often be not considered is the buoyancy effect. When the water reaches the body it begins to buoy it up thus reducing the load on the tyres. This is particularly significant with faster stream flow as the vehicle is more likely to be pushed sideways.
A body-lift helps to minimise this effect as does higher vehicle weight. A tray back ute has less body volume in the water and suffers less from this effect. My weighty old Troopy with its high clearance is also less effected, but its weight may give more problem on soft sandy creek bottoms.
The SUV's with low weight and low body height would be more prone to the flotation peril.
The Suzuki in the video above did not suffer as it was simply full of water and had virtually no buoyancy.

Probably best not to do this

https://www.facebook.com/autocrazeau/videos/1078315015532182/

Unless you have elivated diff and gearbox breathers you should not go over the hubs ...... this is probably THE first mod any body should do to a 4wd.

Some 4wd have elivated diff breathers, but they only go as high as the chassi rails.

OH the one everybody forgets ..... the fuel tank breather ..... it to disapears into the chassis rail on some vehicles.

No trouble ..... this is possibly one of the easiest 4wd mods to do.

cheers

One of the best things to do when confronted with a decent water crossing of tyre depth or more is to pull aside for 10 -15 min and let the vehicle cool down. Good time for a cuppa while you are at it. There is the added advantage of someone else coming through whilst you are pulled over, so you can see how that vehicle goes.

We've done this going into Twin Falls Kakadu, and El Questro gorge amongst many others where the water was up a bit. Gives diffs, gearbox etc a chance to cool down a bit.

Brucek

A number of things determine the wading depth of any vehicle, not the least being the engine air intake but also such issues as the engine fan 'propelling itself' in the water and either breaking under the strain or contacting the radiator (or both), also location of diff and transmission breathers (whilst not being obvious at the time, but 0.05% water in the diffs is enough to destroy the bearings and drive gears if not attended to promptly).

Being an auto vehicle one thing to be particularly wary of is the increase in engine revs as you apply power to exit the water, this can result in fan and radiator damage that is less likely in a manual transmission vehicle. (Personal experience with both 3.0LTD Jackaroo auto and Toyota 100S TD Auto, both broke fans and only marked the radiator (very lucky)).

Depending on the wet season by late May the Penticost could be as little as 200mm, and if so should not be an issue for any high clearance vehicle, the Durack may be an different issue.

Enjoy your trip
Athol

Here's me crossing Kings Creek. Not sure I would do this these days to be honest. You could really feel the water pushing against the 4WD.

Thanks to everybody, there is a good deal of info here.
Keep up the discussion, I'm sure there is plenty more to learn.

Yes Maric we will be taking the Citroen C5 wagon.
Rhonda doesn't want me to take the Peugeot even though it is already set up and has done about 25,000klms of touring to places including Chambers Pillar and the Mereenie Loop.
The Cit. is more comfortable and uses half the fuel, which is a big saving over 18,000klms.
BTW I have already taken the Citroen up the Blackfellows Hand Track and to The Lost City near Lithgow more than once. No water challenge yet though.

Re the wading ability, which we still can't define;
I can undo the air intake from the air box and jam it on top of the airbox with the bonnet.
(Just for the crossing of course).
I will be organizing a breather extension for the gearbox and maybe for the fuel tank.
The snatch strap will be fitted and slung over the roof rack.
I will talk to my mechanic about blue grease for the bearings.
The Pentecost is fresh water I believe, so no issues with starter or alternator.
We wont be crossing the Durack River but we will go through Lawn Hill Creek.
I have already begun work on the blind.
I will be ready to tape up door drain holes.
I will be ready with the WD40.

Nobody has commented yet about silicon on the door seals.
Nor has there been any comments about under bonnet computers, relays etc
Apart from knowing where they are, what do we do to prep them?

The Pentecost river will probably be only 200mm after all this!

NB The Citroen dealer people are not even allowed to drive their cars through puddles?!!?

As well, all the vehicles on our trip must have light truck tyres or similar and an extra spare.
Everything soft and vulnerable underneath will be covered, with say, old plastic garden hose secured with cable ties. I will also be fitting a light gal. stone guard under the sump.
Every nut and bolt under the vehicles will be checked for tightness and cleaned and painted with light coloured enamel paint. and etc.etc. Prep is a huge key.

Three months to go on the 14th of Jan! See the Trip/Gathering section for more info on what we are doing.

Woops.
We will be crossing the Durack River (twice) but not going into Durack River Homestead.
The video of the Durack River crossing is no more scary than the Pentecost.

Refer to your vehicle handbook. I've yet to find one (4WD) that doesn't state the wading depth in the specs section.

Electric fans - so you'll be disconnecting those before you hit the water. Before they chop through teh radiator.

Thanks CraigB

The vehicle handbook says "If you unexpectedly encounter a flooded road and the depth of the water is such that it would touch the underbody of the vehicle, stop immediately and find an alternative route".

But then, they would say that.

We are planning to encounter a flooded road, so preparations will make a difference.

My mechanic says the computer is up high and agrees that the air intake and transmission breather need to be raised. We will have a look for other vulnerablilities.

The ground clearance is adjustable as follows;
Normal 135mm "My estimation"
Automatic on rough road under 65 kph 145mm
Medium max 40kph 175mm
High max 10kph 215mm

The sill height is 175mm above this so I reckon I should be able to get a 400mm wading depth without too much trouble.

If it's the vehicle in your signature then it's not really designed for wading rivers such as the Pentecost.