Blown engine and 2 much water

My friend drives a 2006 BMW 530 xi and just called me and said that because she drove through high water yesterday she caused her engine to blow up. The BMW dealership said she was at fault and would need to pay (a lot of money) to get the engine rebuilt. I don’t know alot about cars but could this be true? There were alot of other cars going through the same water at the time.

I will be interested to see what the experts say. As a non-expert it looks like this:

  1. She drove through high water yesterday.

  2. Not much later, her engine blows up.

The chances of that being a coincidence are nearly zero.

High water can be deep enough to get sucked in through the air intake into the engine. Drivers responsibility to know the limitations and not go there. Other cars have different perameters concernig placement of air intake. Don’t follow me in my Explorer with your beemer unless you like to swim. Some intakes face down, just behind the grille, some face forward ( the explorer faces forward at the grille and affords me about 26" of water depth ). After this is said and done, ask them to show you the air intake on your beemer and gat a mental picture from the outside of your car of how deep water could be to be passable so this doesn’t happen again. Have you ever seen a hummer with a snout sticking up just in front of the windshield ? That is a deep water intake and that hummer could take 60" deep and I certainly wouldn’t follow a hummer with my explorer. Something more to learn about your car that you never knew you needed to know.

The dealer is correct, however your friend should contact her insurance company to see if she is covered for flooding.

Ed B.

If the water was deep enough where it was pulled into the intake ducting and was injested by the engine, it will destroy an engine. If there’s water in any of the cylinders, and the piston comes up, all sorts of nasty things can happen. And that’s because a liquid can’t be compressed.

Your friend might look to her insurance company to if this might covered under the comprehensive section.


Could easily happen, especially on a low-slug car like a BMW. Alot of the time these cars have the air intake pickup mound low to get cooler air, of course this makes it easier for the engine in ingest water whilst driving through a deep puddle.

The chances of that being a coincidence are nearly zero.

Not at all…an easy way to blow an engine. If the engine sucked in water it will get into the cylinder chamber and hydrolock the engine…thus destroying it.

As Ed mentioned…Insurance may cover this.

Thanks for the explanations, especially the detailed ones. it makes sense to me now and I will send these on to my friend. Better late than never I guess. She won’t feel any better now but at least moving forward she (and I) will be better informed auto owners and she’ll still trust her dealership. All is good.

Yup! She is at fault.

As was already stated, by driving the car into high water (likely at too high a speed–after all, she is driving a Beemer!) she caused the engine to ingest some of that water. Since water can’t be compressed as air can, the result is bent/broken connecting rods and God only knows what else. Surely you wouldn’t expect the warranty to cover this type of driver negligence!