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Hydrolock and Honda

My wife’s '08 recently tossed a piston through the engine block after 48,000 trouble-free miles. The dealer is saying this was caused by hydrolock and is not covered under their warranty. The vehicle has never been through more than a inch of water. My question is how long could it operate once fluid got in a cylinder?

Hydrolock could also be caused by a head gasket failure, allowing coolant to enter the cylinder.

This seems like a re-run. The engine stops the instant (fraction of a second) that one of the cylinders fills with liquid and begins its compression stroke.

Understood, but would a failed head gasket cause a sudden complete engine failure, throwing a piston and evidence of hydrolock? The car’s day was driving 300+ miles at highway speed with no issues, turning around and heading back with the engine blowing after 50 more or so.

Yes, and in that case it should be covered by warranty.

Either try at another dealer, or write (don’t call - write) Honda-USA corporate. THEY must prove that hydrolock caused it, and that the hydrolock was caused by you rather than a bad head gasket. Otherwise, they have to honor the warranty claim.

That’s what my mechanic (who’s inspected but never had to service the Honda), my lawyer, and I all thought. The inspector didn’t actually see the engine, he just saw some pictures, which so far the dealer refuses to send me a copy of. Unfortunately, I think it’s time for my attorney to request them.

It would help to know a lot of those tiny details behind this problem (the oil level for one) but it’s always possible the hydrolock diagnosis is wrong.

Hydrolock is impossible if the road was dry or even if it was raining and the car was being driven. Head gasket leak?? Not possible to leak INTO an operating engine. All the pressure is OUTWARDS! In the real world, the ONLY way to “hydrolock” an engine is to submerge it while operating at more than half throttle…

You say “tossed a piston”…You need to explain that in detail.

The repair estimate says the piston went through the side wall of the engine and cracked the transmission case. Oil level was checked pre-trip.

Not possible to leak INTO an operating engine. All the pressure is OUTWARDS!

Not on the intake stroke. Imagine if an intake manifold let go and flooded the intake with coolant. Never saw it hydrolock an engine yet but thinking it’s plausible.

If this was really a hydrolock problem due to coolant from a head gasket breach then this did not likely occur in a matter of seconds. There had to have been symptoms leading up to that breach. Removal of the cylinder head and inspection of the head gasket should reveal if coolant was behind this problem.

The piston did not come out without the rod it was attached to so this story is still very murky to me.

There’s still a lot of questions about the unknown details behind this problem.
One I would ask is this. Were you with your wife when this happened or was she alone?
Two is that you state the oil level was checked pre-trip so who checked it and how much time expired between the time it was checked and the trip?
Three is who performs the oil changes?

Whether is was or wasn’t “hydrolock” that destroyed the engine; for you to be responsible there would be a lot of water in the airbox (the place where the air filter sits) and in the air ducts leading into the throttle body.

Hydrolock on a warm motor in dry conditions isn’t possible due to driver error. You would have to have been driving in a monsoon and hitting huge puddles to get water all the way up to the area where the air intake is located. The inside of the motor compartment would be drenched with water at the time this happened.

Your lawyer can demand all pictures and evidence if this is going to go to trial or deposition. You need to have someone (other than the dealer) who is a recognized expert examine your car for evidence (or not) that the car was driven in wet conditions that could cause hydrolock. If there is no evidence you caused this, then Honda is on the hook to repair the motor. Where is the car now? Is the dealer blocking access to your own car for an inspection?

My guess is this is not hydrolock. Either a piston failed, or the block was defective and failed. Either explanation is more plausible than hydrolock or a sudden head gasket failure.

Let us not forget that Honda uses the alumasil (sleeveless) engine technology. If this system fails and the rings dig into the aluminum cylinder wall, catastrophic engine failure can occur…

Hydrolock is so rare in automotive engines it’s not even a possibility…