Driving through flood water

Richard53

I'm sure you have done no harm at all. Drying the brakes out is about the only thing you need to be aware of if the water has been fairly shallow. The horror stories you have heard are where the car gets properly under water and the interior gets soaked - almost impossible to dry out and a lot of the electronics are now inside the cabin, and if these get wet it can prove very expensive. Insurers often write cars off if they have had a serious ingress of water.


As long as water hasn't entered the air intake, the engine should be fine. If you had done any damage, the car would have stopped dead there and then. A good rule of thumb is not to drive into water beyond the lowest part of the wheel rim, i.e. 4-5 inches, although with care you can safely wade a lot deeper than that. Take the lowest gear to keep the engine revs high (prevents water entering the exhaust) and go steadily, about at walking pace. Remember that water can conceal all sorts of nasties like deep potholes which could be a lot deeper than you expect. If it looks deep, or you don't know the road, either watch someone else get through successfully and follow their line, or put your wellies on and walk it. There is almost always an alternative route that might take 10 minutes longer, but is much better for your peace of mind.


The elderly couple in front of you had probably been driving this road for years and seen it all before!

Marktheshark

Some cars are better than others, the renault megane is one, they dip the relay and lower fuse box quite easily and issues soon start.
Air intakes are low on cars here to meet EU emissions so a check of the air filter to see if its damp is good advice.

s_b

I would never advise to drive through flood water unless you have to to safe lives or its low enough to be below the wheel rims as Richard53 advises.
You have to remember it could enter the breather on the gearbox ,water be sucked up by the low trunkING on say Peugeots to the airfilter and simple things like wheel bearings uj joints etc being compromised on anything other than perfect components /cats getting shattered /discs cracking if hot /looms rotting in joints in the following months,of course on many cars comfort controlled ecus can be fitted into things like door skins just waiting to be ruined

not worth it and not all insurers would pay out if car written off due to negligence in entering the water

bigjl

One of the worst cars for sucking up water is the Clio diesel. The mk2 was well know for it and could hydro lock after going through a deep puddle.

Not sure if the mk3 was altered but I would suspect it was.

A friend with a 730LD siezed the engine going through some flooding just over a year ago. Car was never right afterwards lots of silly electrical problems with sensors. The engine was replaced with a brand new one through Insurance and I believe the total bill was more than £10k.

I agree with other posters that have said the OP is likely in the clear.

BeenThroughItAll

Marktheshark wrote: »

Air intakes are low on cars here to meet EU emissions so a check of the air filter to see if its damp is good advice.

So how does the lower fitment of an air filter affect emissions in an electronically controlled closed-loop system?


It's not air pressure, as there's no measurable difference between 0.3m off the ground and 1m off the ground.


It's not ambient temperature, as there's no measurable difference between 0.3m off the ground and 1m off the ground.


The air is not measurably cleaner 0.3m off the ground than it is 1m off the ground; in fact, it's probably dirtier.


The only conceivable difference is a slight decrease in inlet air temperature, but low does not equate to 'in colder air' - it could be low and right next to the radiator. Lower might also mean a longer pipe run to the inlet tract, which would have to pass through the engine bay, allowing heat soak. Let's also face it - inlet air temperature differences can be easily accommodated by the engine map, using the values from that sensor. You know the one, what's it called? Oh yes - the 'Inlet Air Temperature' sensor.

BeenThroughItAll

Just on the original point though - Between 2000 and 2003 I lived only a mile or so from a ford, which was between 3 and 6 inches deep under normal conditions. There was another, normally about 3 inches deep in the middle of the local village where I used to frequent the pub.


I must have driven through those fords hundreds of times, yet none of my wheel bearings ever disintegrated, my propshaft never snapped, my exhaust never fell apart, my brakes never exploded, my engine never seized, and all of the electrical equipment continued working perfectly.


Also, in that period, I don't know of anyone in the village or surroundings who suffered any misfortune as a result of wading the fords, and most of us did that several times a day on the way to or from work or to the pub or shop.


Many of the horror stories you hear are the result of poor driving (too fast, too slow, wrong gear), or inappropriate risk assessment (too deep, too fast flowing, too slippery underwater, or poor underwater surface).

Richard53

BeenThroughItAll wrote: »

Many of the horror stories you hear are the result of poor driving (too fast, too slow, wrong gear), or inappropriate risk assessment (too deep, too fast flowing, too slippery underwater, or poor underwater surface).

I'd agree with that. Given a level road surface and a known depth of water, even a normal car can wade through quite deep water with no ill effects. My Land Rover 90 had no special adaptations such as axle breathers or snorkel, but I've had the wing tops and door handles under water several times. However, most people who drive through floods don't know what is under the water ahead of them or how deep it gets, and when the car sinks deeper and deeper they don't know what to do and end up climbing out of the sunroof. I think the point is that most parts of a car are not harmed by brief immersion in water (think of how wet the underside gets on a rain-soaked motorway), but the parts that are harmed are harmed quite quickly, expensively and often terminally.

Strider590

Neil_Jones wrote: »

The "don't get water in the car engine" thing normally results from driving too fast through the water in the first place, and it's that more than anything else that forces water up into the intake and seizes up; likewise if you generate enough of a wave for it to splash back up and over the bonnet.

If it makes you feel better, go to the mechanic but as previously stated, there's no real need. The brakes not working initially is understandable as they'll be wet. Once they dry out they'll be fine, if a bit squeaky initially.

You won't get water up into the inlet manifold, most if not all airboxes have drainage holes in the bottom, with air coming in from the bottom, up through the filter and out via the top, it's almost impossible to get water into the engine unless the water is way too deep.

The real issue is stalling due to water in the exhaust, which is why it's always best to let the slow idiots in front go first and then take a run at it in 1st/2nd at a good rpm to keep water out.

The correct speed is one that keep water out of the exhaust, yet doesn't splash water up and around the spark plugs or ignition HT. All the rest of the electrics are safe as water has a very high electrical resistance to low voltages, a car battery will work underwater. Long term damage from exposure to water tends to occur in French or Italian cars, where they use cheap electrical terminations that can corrode and give major issues 6 months later.

bigjl

Strider590 wrote: »

You won't get water up into the inlet manifold, most if not all airboxes have drainage holes in the bottom, with air coming in from the bottom, up through the filter and out via the top, it's almost impossible to get water into the engine unless the water is way too deep.

The real issue is stalling due to water in the exhaust, which is why it's always best to let the slow idiots in front go first and then take a run at it in 1st/2nd at a good rpm to keep water out.

The correct speed is one that keep water out of the exhaust, yet doesn't splash water up and around the spark plugs or ignition HT. All the rest of the electrics are safe as water has a very high electrical resistance to low voltages, a car battery will work underwater. Long term damage from exposure to water tends to occur in French or Italian cars, where they use cheap electrical terminations that can corrode and give major issues 6 months later.

How do you explain hydro locked engines then?

I can assure you the 730LD of my mate was thoroughly hydro locked.

And the air intake on a 61 plate 7 Series is not a simple design and he didn't have a CAI fitted.

A few tiny drainage holes make no difference whatsoever if you are unlucky enough to hit some deep water. It doesnMt have to be deep if you are unlucky. The early mk2 Clio Dci could be hydro locked after going through a decent sized puddle.

Stalling due to water in the exhaust?

Really?

Because people used to fill up the back box of people vehicles with the power washer as a wind up.

Since an exhaust is well, an exit from the engine why would water cause it to stall.

Even stuffing a !!!!!!! in my tailpipe" would do little, a few potatoes might do the trick but unless you stuffed in loads the exhaust would likely just act like a spud gun.

worried_jim

As a 17 year old I went flying through the local ford with my mates in my Mums mk1 mini, water was gushing out the heating air vents! Never 'fessed up to that one. Happy days!