Way off topic but..............

CornRattle

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My mate just phoned me to say that he has driven through about 6 - 8" of standing water and his engine has stopped and will not re-start.

He has a BMW 123d. Could water of this depth have entered the engine?
 
yep but should be fine once it dries out i think. hopefully other will give their opinion
 
Depends really.

It water has got into sensors then yes it may start once it dries out

However if water has been sucked in through the air filter he could have hydro locked his engine. In this case if it won't start and if he tries to do it he cold have done more damage and it is rebuild time.

Does the engine crank ? If it does then probably electrical.

I also think it depends on how fast he hit the puddle/lake
 
Depends really.

It water has got into sensors then yes it may start once it dries out

However if water has been sucked in through the air filter he could have hydro locked his engine. In this case if it won't start and if he tries to do it he cold have done more damage and it is rebuild time.

Does the engine crank ? If it does then probably electrical.

I also think it depends on how fast he hit the puddle/lake

Apparently engine will crank but not start, I think he was only trickling through and it died on him half way through.
 
Mm there is a knack to driving through a puddle. Going too slow can be just as worse.

You should give it plenty of revs and drive it off the clutch. Just keep lots of gasses coming out the tail pipe. He may have let water down it and it could have flooded his cat.

Lots of possibilities and all needs to be checked out.

Flip the air filter out first and check for water here.
 
Mm there is a knack to driving through a puddle. Going too slow can be just as worse.

You should give it plenty of revs and drive it off the clutch. Just keep lots of gasses coming out the tail pipe. He may have let water down it and it could have flooded his cat.

Lots of possibilities and all needs to be checked out.

Flip the air filter out first and check for water here.
that's my thought too.
if the air intake isn't that low i think that he didn't hydrolock the engine. so probably once everything is dry it will start.
 
Mm there is a knack to driving through a puddle. Going too slow can be just as worse.

You should give it plenty of revs and drive it off the clutch. Just keep lots of gasses coming out the tail pipe. He may have let water down it and it could have flooded his cat.

Lots of possibilities and all needs to be checked out.

Flip the air filter out first and check for water here.

Not plenty of revs at all.

That sends all the pulleys going really fast, so when it hits water, it fires it straight around the engine bay.

It also tells the engine, fack me, i need more oxygen, suck harder!!

Just take it easy and just trickle through with just enough revs not to stall. or turn around.
 
do they have an intrrcooler? if so remove it and empty any water inside, happened to a mates astra van and we emptied it and it started up after a little while then.
 
do they have an intrrcooler? if so remove it and empty any water inside, happened to a mates astra van and we emptied it and it started up after a little while then.

It's in the process of getting recovered back to his home. There was water inside of the air filter though so he's fearing the worst.
 
glow plugs out and crank, should blow the water out of the cylinders as it cranks? seen it work on petrol cars like a treat. Have a battery booster on the battery though.
 
8 inches is only half way up the average BMW wheel, so it shouldn't be enough to cause a hydro-lock, but it's plenty for thermal shock. :ohmy:

be interesting to hear the outcome.
 
8 inches is only half way up the average BMW wheel, so it shouldn't be enough to cause a hydro-lock, but it's plenty for thermal shock. :ohmy:

be interesting to hear the outcome.

Apparently the 123d has very low intakes, it was recovered to the local BMW stealer who are convinced it's hydro-lock, they will strip it on Monday to ascertain the level of damage. It's the 2nd one today according to the stealer as earlier a 330d did the same thing and is defo ******.
 
If it turns over, it can't be thermal lock, where incompressible water jams the pistons and prevents it from turning. A drop can be aspirated with no problems so it's most likely electrical.

I wouldn't let them strip my engine!
 
If it turns over, it can't be thermal lock, where incompressible water jams the pistons and prevents it from turning. A drop can be aspirated with no problems so it's most likely electrical.

I wouldn't let them strip my engine!

I agree. If it turns over it is NOT hydrolock. Engine does not need stripping. Almost certain to be something else. So many vulnerable electrical compponents which only need a brief soaking to play up. Diagnostics should bring these up. I had my speedo go bananas after the wife drove my S4 through a deep puddle (she 'thought' the engine was 'sealed' LOL) Got the sensor out and used an airline and hairdryer and it all worked fine.

If diagnostics dont reveal an electrical fault I'd start with the intercooler/air intake and work towards the engine. Then consider the exhaust system. These will probably need taking off and checking but that's a lot less money than an engine strip.

Incidentally the correct technique for puddles is:
1. To use as low a gear as possible and maintain a minimum of 1500-2000 rpm. This moves enough exhaust gas out of the pipe to prevent water being sucked in. NEVER take your foot off the throttle even if you stop. If 1500 rpm in 1st moves you too fast then you should slip the clutch to maintain the revs.
2. Drive though floods in the centre (crown) of the road where it will be shallowest (if you can)
3. If the water Comes as far as half way up your wheel (watch someone else go through first!) consider an alternative route unless you know your intake is high up. Even so at this depth you may well get some water ingress into electrical components etc and if your Catalytic Converter is toasty hot you can damage it from thermal shock. If you can't get any sense of how deep the puddle is. Do a U turn!
4. Ironically you should not go too slow! A steady speed of 5-10 mph pushes a bow wave in front of the car. Behind this (under the engine) it creates a trough of low water. If you drop your speed this trough fills up. For this reason 4x4 off road courses advise that you create a bow wave and maintain it but never let it break over the bonnet - of course this is in vehicles with a snorkel. You should only be creating a small bow wave.

Hope this helps
 
Not plenty of revs at all.

That sends all the pulleys going really fast, so when it hits water, it fires it straight around the engine bay.

It also tells the engine, fack me, i need more oxygen, suck harder!!

Just take it easy and just trickle through with just enough revs not to stall. or turn around.

I didn't mean like 5000 rpm. Just enough to keep the gas coming out of the exhaust and stop it filling with water. So if you need to slow down dip the clutch but keep some revs on
 
A Hydro-locked engine will turn over if the valves are bent by trying to re-start it. Thermal Shock is where the cold water hits a hot engine and causes the crankcase to fracture.
 
Right, just spoke to my mate and here's what happened.
Drove into the 'puddle' behind a string of other vehicles who got through OK, car just died about halfway through (about 6 - 8" deep)
He then tried to start it and it turned but wouldn't fire so he tried again, this time it wouldn't even turn over, apparently the car has 2 secondary air intakes just behind the front fogs.
I'm thinking it's ****** after hearing that.