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A Rock Hydrolocked My Honda?

Honda is saying my 2008 CR-V engine has experienced hydrolock. The car is “Certified” and I’ve had it for six weeks. Here’s the sequence of events:

-Hot, dry So Cal day – great road conditions
-No MIL indicator, temp gauge shoots to “hot” > dash lights, lost compression > pull over
-Engine off/smoking (none from exhaust)
-Coolant tank empty > refill > wait 30min. > 0 leaking
-3 restarts w/difficulty (starts each time)
-Drive car > compression is normal
-Stop car > check coolant (full) > restart the car > start-up/compression fine
-Drive car > temp gauge/compression fine, MIL on
-Stop car > check coolant (full) > restart (no issue) > drive > compression/temp gauge fine, MIL off
-See #s 2 & 3 > check coolant (full) > car won’t turnover/battery dies
-Car towed to the Honda dealership > Honda investigates


Road debris (they suggest a rock) entered my fan and hit a blade, which shot it through the bottom of my radiator. They said they couldn’t spot the puncture until they removed the fan, and said when they did, it was “pouring” coolant. Pouring. During the first overheat, the head gasket blew and created separation between the gasket and the block. Coolant leaked into the separation and into the engine block (mind you the puncture is at the bottom of the radiator), into the cylinders and caused the engine to hydrolock. The engine is finished; the car needs a new one. $7300+tax for a used engine with 57k miles (mine had 70k). “Impact damage” – Honda won’t cover.

I am not a car guy and even to me this sounds ridiculous. Apparently my certified Honda engine can be destroyed by a pebble on a warm, sunny, Southern California day. Is this possible? What’s my next step?

Oh, important sidenote: I checked my fluid levels two days prior to this happening and they were fine.

If I were you, I would contact my insurance company.
This may be covered under your “Non-collision” coverage.
This is the coverage that used to be referred to as “Comprehensive”.

The overheat/gasket failure/hydrolock sequence sounds plausible, but the “rock caused puncture” sounds dubious.

First of all, there’s usually a plastic splash guard under the engine to prevent water ( and rocks) from splashing up onto drive belts.

Second, the fans are encased in shrouds.

Third, the fans blades are typically pitched to suck air through, not blow towards, the radiator. So a rock hitting a blade should be projected back towards the engine, not into the radiator.

Like Tom and Ray say, I’m not buying it!

If the car has been a daily driver for 6 weeks with no loss of coolant and no indication of overheating it would be somewhat apparent that the dealer sold the car in roadworthy condition. Then, after 6 weeks of use the car suddenly has a catastrophic failure that is the textbook case of the driver continuing to operate while severely overheating. The dealer isn’t required to investigate and give a mile by mile and drip by drip explanation for the failure. The scenario in this situation is all too common on this forum.

I am sure what actually happened was the stone hit the rad at highway speeds, the fan had nothing to do with it…Usually though the rock would puncture the AC condenser 1st though… Bottom line is this whole story is very plausible, you have to chalk it up to “unlucky lottery”… Nothing could really be done to prevent it from happening, once the rock strike too place, with the exception of you stopping prior to overheating the motor… NO WARRANTY in the world would cover this, as it has nothing to do with a defect or worn out item. @VDCdriver is right your insurance may cover it though, my aunt has a cobalt and a truck infront of her lost its tread, it whipped up under her car, destroyed the oil pan… It dropped all its oil at highway speeds and blew up as she was trying to pull over to a safe spot… Insurance covered it…

@jesmed, neither am I. I don’t really know, but are you saying that the coolant could still leak into the cylinders through the gasket/block separation even if the radiator was punctured at the bottom?

@VDCdriver, I will contact my insurance agency after I have a better understanding of this issue and the plausibility of it. However, I do not want to pay a deductible and go through insurance if this is an issue with the Honda, itself. The car is 12/12 bumper-to-bumper certified and I’ve only had it for six weeks; if there’s a warning system malfunction or missed, preventable measure here, or if I’m just straight up being played, then I need to know. If this is a problem with the vehicle itself, then Honda needs to pay for it, not me and my insurance company.

The sequence of engine destruction following the radiator puncture makes sense. The sudden leakage, the subsequent overheating, head warping, and severe headgasket breech, the drawing of the coolant into the cylinder to the extent of hydrolocking, it’s all been seen before.

Personally, I also find the cause of the radiator puncture plausible, albiet a one-in-a-million shot. A rock hitting a spinning fanblade is going to ricoche based on exactly how it hits rather than the angle of the blade, particularly if it ricoches off the blade’s edge. Fan shrouds are designed to channel air only and have enough clearance to allow movement of the engine withuot the blade contacting the shroud. I doesn;t take a very big stone to puncture copper.

I think VDC has the best answer. See if your comprehensive would cover it. Other than that, I think you’ve just had a moment of very bad luck. Sometimes stuff just happens.

If the radiator is punctured / leaking, filling the coolant reservoir / overflow tank will do nothing…From that moment on, you were driving on no coolant in the engine…Any filling would need to be done directly into the radiator to fill the cooling system…

That being the case, the engine is toast…

This is all very disheartening, but better to know than to not know.

The car was traveling at 50mph and there was no indication of an issue – not a light, jolt or decompression – prior to the temp gauge going from regular to hot in a matter of seconds and the dash lights illuminating.

@Caddyman, my issue with all of this is that they said that re-filling my coolant tank was the cause of the hydrolock. That when I did that, it flooded the cylinders. I suspect the radiator puncture at the bottom of the component would have drained all the coolant, so I don’t see how it could have gotten into the cylinders. That’s the part I’m not understanding, if anyone could provide some clarification on that, that, and that the MIL would command off if there were catastrophic engine damage. I get that the engine would overheat, but I don’t understand the anatomy of how it would hydrolock.

Yeah, sorry to say, I think Caddyman is probably right that you drove it around on no coolant. Since the temperature sender for the gauge needs to be immersed in coolant, it sent back a false reading, making you think engine temps were fine when they were not.

I suspect, however, that you did not hydrolock the engine. I suspect you fused the pistons to the cylinder walls. It ends up being the same result - your engine is now a paperweight - but the cause is different. If you had no coolant in the engine, then you had no water to get into the cylinders to hydrolock it. However, since you had no coolant in the engine, you heated the metal to extreme temperatures, and when you turned the car off it welded itself together.

I do find it plausible that you punctured your radiator, because the same thing happened to me once. As with your case, it was a freak chance that let the rock be aimed just right to slip past the bumper and the other stuff in the way and hit the radiator. I do not, however, believe that the rock entered your fan first. I believe that, assuming they’re telling the truth, the rock entered the front of the radiator, exited the back, and broke a fan blade on its way out. If you can look at the radiator, you can confirm which direction the rock was traveling by looking at the holes. The exit hole will be ragged, with metal sticking up from it.

I side with the others in saying call your insurance company. I wouldn’t blame Honda for this - the warranty is supposed to cover defects, not freak accidents.

How big was the leak?? Also, at the beginning, the system is under 14psi pressure and will empty very quickly even from a small puncture of the bottom tank (plastic)…But with the cap removed and the pressure released, the leak can be much slower, allowing the system to fill and flood a cylinder, hydrolocking the engine…

Once aluminum engines get THIS hot, they are not repairable. Everything is warped and distorted. Scrap metal…

A BMW tech I know sent me this message, “Your car went down like the Deathstar. Someone shot a photon torpedo through an exhaust vent, thus creating a chain reaction to destroy your engine. It was a one-in-a-million shot.”

Apparently I need to blame the Force. The car was gray.

If they had to remove a fan in order to see the puncture, then the puncture was NOT at the “very” bottom…and therefore, adding coolant as you did would have allowed some of it to be retained in the “very” bottom of the radiator, pumped into the engine, past a failed gasket, and into a cylinder.

But either way, by hydrolock or by melting of cylnder wall/piston, the engine is toast, so it’s a moot point.

The reason I suspect melting is that OP did not, unless I’m reading it wrong, fill the radiator, but instead filled the reserve bottle, and then the reserve bottle stayed full because the radiator wasn’t pulling anything out of it. Anything in the bottom of the radiator would as you said have been pumped into the engine, but this should have happened the first go-around, when he just lost coolant. It sounds like he pulled over right away and shut down as the gauge went to hot, so he probably didn’t warp the head until he restarted it and, thinking he had coolant in the engine, trusted the temperature gauge when it wasn’t reading properly due to having no water around the sensor.

The reason this may be important is that if the dealership mechanic was wrong about the cause of the failure to crank (hydrolock vs seized), he might be wrong about the cause of the radiator leak - what if the radiator was weak from the factory at that point and sprung a leak without being hit by a rock? If that were the case, then Honda should cover the repair rather than OP’s insurance company.

What I’m driving at is that OP should eyeball the radiator damage himself and, if he’s unsure of what he’s looking at, take photos and post them up here. Let’s make sure the dealership is right about the cause of this thing before we tell him to go get his insurance rates jacked up.

“my issue with all of this is that they said that re-filling my coolant tank was the cause of the hydrolock. That when I did that, it flooded the cylinders.”

The hydrolock is what prevented you from starting the engine on the sixth attempt after overheating. It is not the cause of the engine failure but does indicate the extent of the damage.

If the radiator had suffered a natural failure and the vehicle was driven two more times after overheating would the engine damage be covered be the warranty? Probably not.

Agreed with shadowfax on the probable sequence of events.

Unfortunately, it seems to be a common misconception that adding coolant to the reservoir is the same thing as adding coolant to the radiator…

In hindsight I too am inclined to agree with Shadow. Seizure sounds more likely that hydrolock.

To the OP- Regardless of how it happened, it is highly unlikely this is Honda’s fault… Like I said above you won the “unlucky lottery”… As others have said motors today are not very tolerant of being over heated once, to say nothing about 6 or 7 times in quick succession. I understand your frustration, and it does suck but at this point all you can do is try to lick the wound and move on… Call your insurance co, pay the deductable and drive on…

A punctured radiator has nothing to do with the build quality of the car and a blown head gasket can certainly hydrolock an engine.

Point 1 is that it’s an unfortunate accident.
Point 2 is that it was a preventable accident, puncture or no puncture. The engine temp does not shoot to H in seconds nor does it overheat badly enough to blow a head gasket in seconds. Monitoring of the temp gauge should reveal if abnormal overheating is happening and this means stop then and there, do not pass GO, and do not collect 200 dollars.