DEEP Water X-ings - When stuck do u turn engine off or leave it running??

[rob_macca67 Avid PP Poster! Find all posts View Profile Close rob_macca67]

Guys......

Just wondering here..... when u do get stuck during a water crossing, what to people do with their engines.... Do they keep them running to prevent water travelling back up the exhaust or do they turn them off?? I should also mention I'm referring to DEEP Crossings......

rob

[wooley Avid PP Poster! Find all posts View Profile Close wooley]

Personally I'd never turn it off.

[D4D Addicted PP Member Find all posts View Profile Close D4D]

Personally I'd never turn it off.

x2 got to keep the positive pressure going

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Definately keep the engine running!

However with the modern motor vehicle if you get stuck in deep water, you are probably screwed, once the computer goes under water, game over. Your car will fill up extremely fast once you get stuck in water!

Cheers Andrew

[Tazdevil Moderated member Find all posts View Profile Close Tazdevil]

My Thoughts would be..

Leave it running, weather you are stuck in water, Mud, Ruts or just hung up. you know its running and you wont have a problem with getting it started.

[rob_macca67 Avid PP Poster! Find all posts View Profile Close rob_macca67]

That's what I had been thinking.... but I have been watching a few Youtube Clips of people trying their luck on Nolans Ck up at the Cape & I was surprised at some of the comments u hear in the background about turning off the engine when someone gets stuck.....

I realise if u get the computer wet its lights out usually, but in the 150's, where is the computer located ??

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Depends, if you don't have a snorkel then I would definately kill the engine before the water did petrol or diesel although the petrol will probably die first anyway due to the water on the electrics. If you have a snorkel then I would keep it running you just may be able to get a bit of traction if lucky. And yes I have seen a few do crossings without snorkels and never have an issue but get snagged on some thing and your screwed with out a snorkel, water blind will do jack shit while just sitting there as most would know..........Cheers Steve

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

If you attempt a "deep" crossing without a snorkel well you deserve whatever you get.

If you get stuck without a snorkel and the intake is below water level you will have a second or 2 at most before your motor sucks in the water, if its a diesel it stuffed instantly, a petrol might have half a chance to be drained and restarted.

If you get stuck and don't fill the motor instantly then turning of the motor with the exhaust underwater can cause water to be sucked up through the exhaust and into the motor.

Always keep the motor running.

I believe the computer is in behind the glove box.

U tube videos probably aren't the best place to learn about 4wdriving

Cheers Andrew

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

""can cause water to be sucked up through the exhaust and into the motor."" Excuse my ignorance there AJ but how does it get sucked back into motor ?? what causes it to do that ?? By a vacuum of some sort ?? How quick would it come back up into motor ??...Cheers steve

[Sako85 Member Find all posts View Profile Close Sako85]

""can cause water to be sucked up through the exhaust and into the motor."" Excuse my ignorance there AJ but how does it get sucked back into motor ?? what causes it to do that ?? By a vacuum of some sort ?? How quick would it come back up into motor ??...Cheers steve

It won't get sucked back in, but if the water level is above the valves it can run up the exhaust, filling the exhaust manifold/s, then into one possibly two cylinders depending on what position the crank stops when the pressures balance out. There will usually always be one (or a pair of) inlet and exhaust valve/s open at any one time. Ultimately allowing the water, mud, tadpoles in.

I definately keep the car running, even if it is for an hour or two. I have however turned my car off in the past when very bogged whilst solo and had to walk out for help. See below photo... There is 4" of lift and 35's under that waterline


The car started straight up and drove home after an epic snatch session, but it killed the clutch as it had been underwater for a few hours.

[wooley Avid PP Poster! Find all posts View Profile Close wooley]

drove home after an epic snatch session

nothing better than an epic snatch session...

[outback7 Banned Find all posts View Profile Close outback7]

You have gotta keep that engine going and live in hope. Once you stop the engine it's game over with whatever your driving. I know it's hard when you see that water come rushing in, but just keep on going for as long as you can. I reckon to be absolutely safe, no where higher then half way up the front wheel arch on the computer rigged vehicles. I know you can go higher than this, but we are talking minimal risk here. The ECU or the ECM is pretty high, up under the dash but you still have your fuse box inside there which is pretty low. Plus, these days I hate getting wet carpets, been there and done that.
The Roo.

Like Roo....I hate wet carpets...lol Always walk it, if you can before you cross. Also been there done that. If I don't have to do a water crossing i won't.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

""can cause water to be sucked up through the exhaust and into the motor."" Excuse my ignorance there AJ but how does it get sucked back into motor ?? what causes it to do that ?? By a vacuum of some sort ?? How quick would it come back up into motor ??...Cheers steve

A quick check of my rig shows that the exhaust manifold enters the motor around the 800-900mm above ground level (hard to measure so thats a rough estimate) the exhaust outlet is 500mm above ground level. In even a moderate water crossing its not hard to see that when stuck, which also oftens means sunk ito the sand or mud, that the exhaust manifold could be below water level.

Add to that the exhaust will have positive pressure (above atmaospheric) whilst the engine is running, it is also full of hot exhaust gasses, as is the motor and combustion chambers. Stop the motor in water and you loose the positive pressure in the exhaust, rapid cooling of the system due to water causes a vacuum, a vacuum will suck water up and possibly into the engine.

Cheers Andrew

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

Depends, if you don't have a snorkel then I would definately kill the engine before the water did petrol or diesel although the petrol will probably die first anyway due to the water on the electrics.

In the past that would be true, but now days as diesels have just as many electrics as a petrol engine, if not more.
If the engine can get air, in either Petrol or diesel, you should be right, just dont let a hot engine go in the water cause that will cause more problems than water getting into the electrics

[winniliss Avid PP Poster! Find all posts View Profile Close winniliss]

nothing better than an epic snatch session...

Now that was funny Wooley,

Winston.