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Discussion Starter #1 (Edited)
[Sorry for the long tale but it's a good read]

My 2007 JK has about 120,000 miles on it. Just before Christmas I ran out of gas at night (my daughters, both home from college, had been joyriding it around town getting LOTS of attention earlier in the day) and AAA came with my two free gallons of gas. Unfortunately, the moron did not realize that the two gallons he put into my tank were diesel, not regular unleaded. Neither did I.

Now the story gets interesting.

The vehicle started, but 1/4 mile away it died. The same AAA contractor towed me to my mechanic. The next day I heard that my fuel pump had failed. The following day I heard that the pump had been replaced, and that the fuel system was basically pure diesel, which had caused the fuel pump to fail. My mechanic had tried to start and drive the vehicle a number of times after replacing the fuel pump, and it didn't start, and that's when he decided to check the fuel itself and detected the diesel. Meaning, diesel ran through the new fuel pump as well. Then he flushed the fuel system, put in regular unleaded, and the car seemed to work OK.

Fine. I paid the mechanic and filed a claim with AAA for about $1,000.

I took the jeep on a run for about 120 miles with no performance issues a couple days later.

A couple days after that, I left on another day trip but my engine began making a very metallic knocking going up a grade. I called AAA again and got towed 75 miles to my special jeep mechanic because I wondered if this was still an aftershock from the diesel thing. A couple days later this second mechanic told me three of my rods were destroyed and that he smelled diesel fuel in the oil that he drained into the pan. How did diesel get in the lubrication system, I asked. He said that diesel won't burn in the carburetor but runs down the walls and seeps through some seal into the lube system.

Why did it take a week and over 200 miles of driving to finally damage my engine, I asked him. He said diesel has no lubrication properties, so it takes a little time (e.g., a few days and 200 miles) for the degradation in the engine to finally take hold. That's why the engine didn't fail immediately after I picked it up from the first mechanic.

But then, this specialized mechanic says that it is possible that my engine was ready to fail already, and the diesel just put it over the edge. I want to update my claim to AAA for both the fuel pump and a rebuilt engine (now a total of $8500), but the mechanic is unwilling to openly state that "diesel caused the engine failure."

So here are my questions:

1) Do 2007 JK engines (V-8, 6 cylinder) fail as early as 120,000 miles or can they be counted on to last a lot longer?

2) Was my first mechanic responsible for the engine failure, because he ran diesel through the new fuel pump and did not know about that other situation, where diesel can seep into the lube system?

3) The second mechanic said that diesel seeps into the lube system from the carburetor. Is this a high probability occurrence? How could this have happened if the fuel system had been cleaned of diesel by the first mechanic? Does it take a lot of diesel to ruin lube in the engine, or just a little?

4) How long does it take for an engine to fail after it gets some contaminant (like diesel) into the lube system? A day and a few miles? Or a week and 200 miles?

5) I do not believe in coincidences. So if the engine failed a couple hundred miles after flushing the fuel system, and the oil smelled like diesel, then the damn engine failed because of the diesel, and not because it was already on the point of failure. Is that the right conclusion?

6) Has anyone on WF lived through this experience? How did it come out?

Thanks for any and all replies.
 
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I think plenty of 3.8’s have failed before 120,000 miles. I doubt enough diesel was able to get into the system to cause the issue. Rods are usually destroyed because of hydro locking type situation.
 

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I think that you would have a valid claim against AAA but there’s no way you’ll get $8,500 from them. At most, you can likely collect the initial $1k in repair costs and then the cost for a comparable engine with the same mileage. A new engine would be considered unjust enrichment.

The main reason I say this is because I listen to a very reputable talk show every day that deals with issues like this all the time. He takes calls from people on many topics and high mileage vehicles are very common.

I hope they can help you get back to where your Jeep was prior to this.
 
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Discussion Starter #4
I think that you would have a valid claim against AAA but there’s no way you’ll get $8,500 from them. At most, you can likely collect the initial $1k in repair costs and then the cost for a comparable engine with the same mileage. A new engine would be considered unjust enrichment.

The main reason I say this is because I listen to a very reputable talk show every day that deals with issues like this all the time. He takes calls from people on many topics and high mileage vehicles are very common.

I hope they can help you get back to where your Jeep was prior to this.

Thanks. My $7400 quote was for a rebuilt engine ($5500) plus labor. What do you think the depreciated value would be for a relatively low mileage engine if not $5500?
 

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I think plenty of 3.8’s have failed before 120,000 miles. I doubt enough diesel was able to get into the system to cause the issue. Rods are usually destroyed because of hydro locking type situation.
Explain hydro locking in more detail, please. Can poor maintenance cause this, or is it just a matter of engine age and sheer probability?
 

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I think plenty of 3.8’s have failed before 120,000 miles. I doubt enough diesel was able to get into the system to cause the issue. Rods are usually destroyed because of hydro locking type situation.
Explain hydro locking in more detail, please. Can poor maintenance cause this, or is it just a matter of engine age and sheer probability?
Hydrolocking occurs when you get fluid in the combustion chamber that doesn’t combust and is relatively incompressible. Usually water. Since it doesn’t compress, as the piston comes up as the crankshaft turns, the connecting rod breaks or bends, or a piston cracks, and the engine is destroyed. Also, the pressure could force some of the diesel fuel past the piston rings and down the sides of the pistons to the oil pan, which would explain why you have diesel in your oil.

Just speculation, but I’m guessing the mechanic pumped a bunch of diesel fuel into the engine while trying to start it before realizing there was diesel in the system. What he should have done, in addition to getting all the diesel out of the tank, lines, etc., is pull the spark plugs and stick a vacuum hose into the cylinders to suck out any fluid.

If I’m right, as would happen with water, the liquid diesel didn’t compress and one or more of your rods were bent, or the engine was damaged in some other way, for example the crankshaft or a piston. That would explain the loud noise you heard. Why you were able to drive a while is a mystery though. Usually damage from hydro lock is pretty evident immediately.
 

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Hydrolocking occurs when you get fluid in the combustion chamber that doesn’t combust and is relatively incompressible. Usually water. Since it doesn’t compress, as the piston comes up as the crankshaft turns, the connecting rod breaks or bends and the engine is destroyed. Also, the pressure could force some of the diesel fuel past the piston rings and down the sides of the pistons to the oil pan, which would explain why you have diesel in your oil.

Just speculation, but I’m guessing the mechanic pumped a bunch of diesel fuel into the engine while trying to start it before realizing there was diesel in the system. What he should have done, in addition to getting all the diesel out of the tank, lines, etc., is pull the spark plugs and stick a vacuum hose into the cylinders to suck out any fluid.

If I’m right, as would happen with water, the liquid diesel didn’t compress and one or more of your rods were bent. That explains the loud noise you heard. Why you were able to drive a while is a mystery though. Usually hydro lock is pretty evident immediately.

correct but it would have hydrolocked in the shop not 320 miles later. Generally on an injection engine the injectors would not let enough diesel pass before plugging up. Not saying anything is not possible but my guess OP is in for a long fight. Hopefully not but I can see a long list of expert witnesses being lined up to testify if it gets that far.


going up a grade and metalic noise almost sounds like it could have been detonation.
 

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If I were OP, I’d see if the damage is covered by insurance. If so, then, see if AAA will pay his deductible, given their mistake in putting the diesel in. The deductible presumably will be a whole lot less than paying for the entire repair.
 

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First any mechanic who referenced a carburetor on your vehicle has zero credibility

Next putting diesel in gas station underground tanks has happened and vehicle tanks and pumps and injectors were sometimes replaced but did not cause engine failure


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Thanks. My $7400 quote was for a rebuilt engine ($5500) plus labor. What do you think the depreciated value would be for a relatively low mileage engine if not $5500?
Sorry, I don’t know. You can call a few junkyards and check. I think I’d get a quote on rebuilding yours and use that for negotiation.
 

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I have known of people who accidentally ran diesel in a gas engine. None of them ever destroyed the engine. I ain't saying it isn't possible, but it would seem to need more to the story, like excessive cranking and somehow getting fairly large amounts (respectively) of diesel fuel in the combustion chamber. As mentioned, liquids like diesel fuel (and water) don't like to compress. So it could bend rods if too much fuel that won't burn made its way into the combustion chamber. But that begs the question, how did all that diesel fuel get into the combustion chamber. The only way I could see it happening is someone using starting fluid to try to get it running with the diesel still in the fuel system. That could possibly cause enough diesel fuel to be injected into the cylinder while at the same time providing enough force to bend the rods when the diesel fuel won't compress. But I am just guessing.
Good luck with your saga.
Now is a good time to look into a small block chevy upgrade.
 

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Discussion Starter #14
Hydrolocking occurs when you get fluid in the combustion chamber that doesn’t combust and is relatively incompressible. Usually water. Since it doesn’t compress, as the piston comes up as the crankshaft turns, the connecting rod breaks or bends, or a piston cracks, and the engine is destroyed. Also, the pressure could force some of the diesel fuel past the piston rings and down the sides of the pistons to the oil pan, which would explain why you have diesel in your oil.

Just speculation, but I’m guessing the mechanic pumped a bunch of diesel fuel into the engine while trying to start it before realizing there was diesel in the system. What he should have done, in addition to getting all the diesel out of the tank, lines, etc., is pull the spark plugs and stick a vacuum hose into the cylinders to suck out any fluid.

If I’m right, as would happen with water, the liquid diesel didn’t compress and one or more of your rods were bent, or the engine was damaged in some other way, for example the crankshaft or a piston. That would explain the loud noise you heard. Why you were able to drive a while is a mystery though. Usually damage from hydro lock is pretty evident immediately.

So if your scenario here is correct, is my first mechanic responsible for my engine failure? Could the AAA towing guy credibly claim to be only responsible for the first failure, not the engine itself?
 

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Discussion Starter #15
correct but it would have hydrolocked in the shop not 320 miles later. Generally on an injection engine the injectors would not let enough diesel pass before plugging up. Not saying anything is not possible but my guess OP is in for a long fight. Hopefully not but I can see a long list of expert witnesses being lined up to testify if it gets that far.


going up a grade and metalic noise almost sounds like it could have been detonation.

Let me clarify. Mechanic #1 found the diesel and cleaned the fuel system, then put unleaded into the tank. He said that there might still be traces of diesel in the fuel and told me to be sure to use 91 octane for a couple fillups. Vehicle ran fine for about 200+ miles then had the engine failure (destroyed rods). Could the fact that the system was mostly gasoline explain why the rod failure was slow, not as fast as you think it should be?
 

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No it was NOT the diesel
You could pour a little diesel in you tank with no effect

If an injector plugged and that cylinder ran lean for awhile that could damage engine but no via lube issue or rod bearing


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Let me clarify. Mechanic #1 found the diesel and cleaned the fuel system, then put unleaded into the tank. He said that there might still be traces of diesel in the fuel and told me to be sure to use 91 octane for a couple fillups. Vehicle ran fine for about 200+ miles then had the engine failure (destroyed rods). Could the fact that the system was mostly gasoline explain why the rod failure was slow, not as fast as you think it should be?
I would not expect rod failure like that 200+ miles down the road. If the diesel was going to blow up your motor I would expect it to have done so right away. I can't see how the diesel fuel could have bent your rods 200+ miles later, regardless of what the AAA guy or the mechanic did.
 

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So if your scenario here is correct, is my first mechanic responsible for my engine failure? Could the AAA towing guy credibly claim to be only responsible for the first failure, not the engine itself?
I’d start with the irrefutable fact that the AAA guy put the wrong fuel in the car. Let AAA explain why they shouldn’t be responsible for the whole mess.

If they try to blame the mechanic, have your insurer contact the mechanic’s insurer and work out a shared payment.

Could the engine failure be completely unrelated to the diesel thing? Perhaps. But connecting rods not otherwise defective don’t typically bend or break under normal use, even at high mileage.
 

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Over the Years I have seen and been told of a number of engines both Cars and Trucks that ran with gas in a diesel engine or diesel in a gas engine . A friends wife put gas in a new jeep (diesel) and It died after 8 miles (going home) it was fine after cleaning it and the filters out . I also seen a new diesel pickup truck go 35 miles on gas before it was found not to be diesel fuel . The dealers lube guy filled it with gas before the new owner picked it up it is still going fine years later . I do not know what happen to your wrangler but if you drove 200 miles after the diesel fuel was cleaned out you may have a problem .
 

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It would have taken a lot of diesel in a cylinder to even begin to hydrolock. Water in the cylinders causes hydrolock when there is a lot of water in the cylinder. Water in the fuel won't do it. Generally hydrolock is caused by excessive intake of water through the air intake system as the result of submersion of the front of the vehicle in water not the fuel system.

Diesel is a fuel, just a very low ignition fuel that ignites as a result of the high compression ratio in the cylinder (generally around 22:1) while our gas engines require a spark plug and a high volatility fuel (gasoline) because of the relative low compression ratio of the engine (about 8.5 to 1 I believe).

When the diesel was added to the tank, the fuel system would not have seen pure diesel, for the tank is not really empty when the engine dies from fuel starvation.

When the diesel is sprayed into the cylinder it will mix with the air that has been sucked in, it will just not combust. On the exhaust stroke the diesel/air mixture would be expelled into the exhaust system. Now it is possible that the engine was cranked long enough to expel enough diesel/air mix into the cats to plug them. That back pressure would be enough to cause the engine to run poorly after pure gas was put in, but would it be enough to bend/break a connecting rod? I don't know.

There have been enough issues around diesel accidentally pumped into a gas tank that the opening in the fuel filler and fuel nozzle are different sizes. This difference initially came into play because of the leaded/unleaded fuel where a vehicle designed for unleaded fuel had the smaller opening as did the fuel nozzle. As leaded gas disappeared from the retail distribution system the opening and nozzle smaller size was retained while auto diesel used the larger size. Those who have operated diesel PUs and filled them up at pumps for over the highway trucks at truck stops know their nozzles are even larger (they also have tanks many times larger than the fuel tank on a car/piclup/Jeep.
 
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