2012 Audi A6: Drove through modest puddle and now New Engine?


The intercooler for the turbo failed in some way that allowed water to enter it, and the turbo pushed the water into the engine.

Since the intercooler sits very low at the front of the vehicle, it’s the only way I can think of how water got into the engine.



My Insight has a nice high snorkel:


That is essentially similar to the intake on my Outback, but I guess if I was to plunge–far too fast–into a puddle deeper than the OP’s friend would admit to, my engine could also wind-up hydro-locked.


On a sophisticated vehicle like this one, would it be possible to simply (electrically) fail the valves open (for some predetermined time delay) every time the engine stalled out (for whatever reason)?

Or are these valves mechanically bound to the camshaft like in my pedestrian vehicles?

I’m going to go take a closer look at the spot where this happened. It’s a very modest dip as you reach the traffic light coming out of the Mall. I don’t go to the Mall much (maybe once or twice a year for Craftsman tools), but I’ve been here a while now and I can’t remember any appreciable water pooling up at this spot. If it did, with the thousands of vehicles going through there daily, I would’ve seen or heard of disabled vehicles just passing by on the main drag.

As Dr. Henri Lee famously said, “some sing wrong here”…


Why would you want that kind of complex system. Plus the manufactures have a reasonable expectation that you won’t drive their vehicles through deep water. I really don’t see the need for all this concern about the co-workers problem when it is insurance settled and the whole story will never be known.


It might, however, be possible to place the induction system snorkel in a place better protected from water. However that does not mean a loose nut behind the steering wheel couldn’t damage the engine from some other cause.


My 2010 Kia Forte’s intake is also similar. If I found myself in 30 inch deep water I would probably be in serious trouble.


Just dropped off my garbage and drove by the scene of the crime. The “dip” in that Mall exit ramp is SOOOOoooo subtle you almost cannot see it, However, the ramp does have a modest downgrade to it, but there’s also a HUGE concrete curb-style storm water drain right there at the stop light to take away any collected water…

I’ll have to remember to drive by during the next monsoon. Maybe that storm water drain is not connected to the system on the main drag, or the main drag is dumping water back out through it, completely flooding the bottom of that ramp.

I still cannot believe his engine flooded right there …


If little to no water got into the engine, then it wouldn’t hydro lock. The most likely conclusions are

  • the shop misdiagnosed it as a hydro lock, when it isn’t
  • water somehow got sucked into the engine, and it is a hydro lock
  • water got in somehow else, like from the cooling system


If you still can’t believe it flooded right there, is there any chance it flooded somewhere else . . . much deeper . . . and your coworker is not telling you the whole story, because he’s embarrassed?

I live in Los Angeles . . . not an area known for rain . . . and we get a few cars with hydrolocked engines every year. So it’s not an unheard of phenomenon. And it’s ALWAYS the driver’s fault. Driving where they shouldn’t be, or driving when they shouldn’t be, and typically misjudging the depth of water


I think your friend is fudging the truth a bit to deflect blame away from himself. This personality trait exists with other problems also. One I’ve seen a number of times is a car towed in for a No-Start condition with a rod sticking through the block. The engine is full of fresh oil and it has a new oil filter on it. The usual response is “No it wasn’t making any noise. I just went out in the morning to go to work and it wouldn’t start”. B & S…

Or the lady who drove a GM car with the LF tire locked and skidding for 8 blocks to the tire store when the rotors wore out and the caliper piston dug into the cooling vanes of the rotor. "No, the brakes have not been making noise…"
The tire blew out as she entered the lot with an 8 block long skid mark behind her.

Yes, a car can easily be hydrolocked and it’s not a rare thing to occur.

It was common back in the 80s for the CIS injected VW Rabbits to hydrolock on gasoline from the injectors when something went haywire in the FI system. I’ve never seen engine damage from this particular quirk.


…but a new bottle of Coke is only $1.75 and not $11,000


…and get your engine hydro-locked?


I think Tester may be on to something.


If he was really getting on the go pedal the throttle was open and the engine was sucking the air in hard.
That would also draw more water in than if he went through a puddle gently.


Regardless how the water entered the engine I am curious how the water catastrophically damaged the engine. The only hydrolocked engine that I have seen with mechanical damage was a small diesel tractor that the owner had steered into a pond and when he was unable to crank the engine with the key he towed the tractor with a pickup and repeatedly popped the clutch. The starter cannot produce enough torque to bend connecting rods or break pistons. There is surely a great deal more to this story that needs to be told.


RK, a running engine can do that kind of damage when brought to an instant stop.


It’s possible but seems quite unlikely that the engine could suddenly gulp enough water to do serious damage. As soon as water begins to be ingested an engine would stall. Could the car have been traveling at wide open throttle in low range when it suddenly gulped water into the intake, then into one cylinder without drowning out the spark on other cylinders?

Like so many puzzling situations posted here this one would be great to see the rest of the story.


That is exactly what happens. Only has to get into one cylinder, instant stop, massive damage.


Rod_Knox, an engine running at, say, 3k RPM has tremendous stored kinetic energy in the moving cylinders. The water is not compressible and causes the cylinder to try to come to a sudden stop. Something has to give, eg, the connecting rod bends, or the valves are forced out, bending them. Or something else yields.

edit, to elaborate a bit more, the one cylinder that hits the water could possibly stop, but there are other cylinders moving and via the crank shaft and connecting rods are pushing that one cylinder with a lot of force, which can cause the connecting rod to bend or break.