Can diesel in gas engine ruin catalytic converter?

[Lindaak]

Due to a fuel tanker truck accidentally dropping diesel in the premium tank at a gas station, I unknowingly filled my almost empty VW Passat with the contaminated fuel. According to my dealer, the oxygen sensors and catalytic converters had to be replaced. The fuel transport company insists the fuel and emissions systems are not connected. Therefore, they only want to reimburse for the fuel and fuel tank flush. Thoughts?

[Berkut]

Did you actually start and run the car on diesel, or just fill the tank with it?

[danceswithcats]

I'd say the blame is easy to establish, without finger pointing. Let the fuel company representative meet with you at a VW agency, and let the online diagnostic unit/emissions test sampling be the final answer.

If the oxygen sensor is producing appropriate values to the ECM, and the catalytic converter isn't damaged, then the OBD will show no codes set, and your tailpipe test will be acceptable for the jurisdiction in which your vehicle is operated.

Should VW allege that the exposure shortened the life of these components, then a urinating competition is likely to ensue. Good luck.

[Rick]

Originally Posted by Lindaak

Due to a fuel tanker truck accidentally dropping diesel in the premium tank at a gas station, I unknowingly filled my almost empty VW Passat with the contaminated fuel. According to my dealer, the oxygen sensors and catalytic converters had to be replaced.

This could be correct, but I don't have enough info to evaluate for sure. Did you drive the car after the fill up? When it started to misfire/run rough did you stop right away, or did you continue to try and drive until the car would not go any further? A misfiring engine can destroy a cat in almost no time. This is why converter are monitored in OBDII cars. BTW what year Passat are we talking about?

The fuel transport company insists the fuel and emissions systems are not connected. Therefore, they only want to reimburse for the fuel and fuel tank flush. Thoughts?

This is like saying that your arm is not connected to you leg, and an infection in one could not cause a problem in the other. In other words total BS. Of course they do not want to spend any money they don't have to, but the damage is their fault.
Over the years I have dealt with many mis-fuelling problems (Gas in diesel tank, water in gas tank, and diesel in gas tanks) I have had to drop tanks, to remove ALL the water, change fuel filters, replace injectors, fuel distributors, and flush the lines. I have never had to change O2 sensors or cats, but emission standards are much tighter now, and systems are less tolerant such things.
Assuming that you have a late model (OBDII) VW, I would expect as a minimum you will have to have the tank flushed, fuel filter(s) replaced, and new fuel installed. Codes cleared and a test drive.
If the fuel company balks at the new converter, then tell them that they will have to pay for a technician to test drive the car and set the readiness byte to prove that that there is no damage to any of the other downstream systems (converter, O2 sensors etc) If the technician can set the readiness byte that means that all systems have been tested and report that all is OK. If the readiness byte won't set, then something is not right.
If I can answer any further questions, feel free to ask.

[Lindaak]

Originally Posted by Berkut

Did you actually start and run the car on diesel, or just fill the tank with it?

Car started at the station without a problem, drove it 2 blocks to work, drove it 70 mi. total (3 starts, all difficult with sputtering and poor acceleration first mile or so) before tank flushed. Service and I didn't know about the diesel till I went to the station after the flush and was told about the contamination and where to send my expenses. Car was running fine but "Emissions Workshop" warning came on intermittently. Dealer said to bring it in at my convenience to turn off warning light. Drove another 3 days (about 150 mi.) before doing so, then dealer said catalytic converters and O2 sensors had to be replaced.

[Lindaak]

Originally Posted by danceswithcats

I'd say the blame is easy to establish, without finger pointing. Let the fuel company representative meet with you at a VW agency, and let the online diagnostic unit/emissions test sampling be the final answer.

If the oxygen sensor is producing appropriate values to the ECM, and the catalytic converter isn't damaged, then the OBD will show no codes set, and your tailpipe test will be acceptable for the jurisdiction in which your vehicle is operated.

Should VW allege that the exposure shortened the life of these components, then a urinating competition is likely to ensue. Good luck.

Thanks, I'm already beyond initial meetings/contacts and unfortunately did not ask for the old parts when I had the work done, but VW service manager is trying to get me printout of OBD to bolster my case with fuel co.

[Lindaak]

Originally Posted by Rick

This could be correct, but I don't have enough info to evaluate for sure. Did you drive the car after the fill up? When it started to misfire/run rough did you stop right away, or did you continue to try and drive until the car would not go any further? A misfiring engine can destroy a cat in almost no time. This is why converter are monitored in OBDII cars. BTW what year Passat are we talking about?

(See reply to Berkut) I drove about 70 mi., but it ran fine once up to hwy speeds. It's a 2000 Passat, had about 61-62K on odometer at time of incident--Lindaak

This is like saying that your arm is not connected to you leg, and an infection in one could not cause a problem in the other. In other words total BS. Of course they do not want to spend any money they don't have to, but the damage is their fault.

I totally agree!--Lindaak

Over the years I have dealt with many mis-fuelling problems (Gas in diesel tank, water in gas tank, and diesel in gas tanks) I have had to drop tanks, to remove ALL the water, change fuel filters, replace injectors, fuel distributors, and flush the lines. I have never had to change O2 sensors or cats, but emission standards are much tighter now, and systems are less tolerant such things.
Assuming that you have a late model (OBDII) VW, I would expect as a minimum you will have to have the tank flushed, fuel filter(s) replaced, and new fuel installed. Codes cleared and a test drive.
If the fuel company balks at the new converter, then tell them that they will have to pay for a technician to test drive the car and set the readiness byte to prove that that there is no damage to any of the other downstream systems (converter, O2 sensors etc) If the technician can set the readiness byte that means that all systems have been tested and report that all is OK. If the readiness byte won't set, then something is not right.
If I can answer any further questions, feel free to ask.

The fuel co. only said to send them all expenses, no guidelines. After I submitted them they implied that I'd been misled by the dealer because catalytic converter and O2 sensor replacement is at the "mechanic's discretion, as there is no diagnostic test that can support the damages were a result of a fuel contamination." Now I'm trying to come up with that support to save on legal expenses.

[Mr. Slant]

What was the year and mileage of this vehicle?

[Rick]

Originally Posted by Lindaak

The fuel co. only said to send them all expenses, no guidelines. After I submitted them they implied that I'd been misled by the dealer because catalytic converter and O2 sensor replacement is at the "mechanic's discretion, as there is no diagnostic test that can support the damages were a result of a fuel contamination." Now I'm trying to come up with that support to save on legal expenses.

Well there is the truth and then there is the whole truth. The statement

as there is no diagnostic test that can support the damages were a result of a fuel contamination.

is on it's face a true statement, but not the whole truth. On the cars I teach on (which also use Bosch fuel management systems) there are something like 20-25 seperate diagnostic trouble codes to indicate problems with one or the other oxygen sensors, or with the catalytic converter. None of these codes have a description of "Hey some idiot put Diesel in the premium tank" So in this they are correct. But since the check engine light was not on before you put their adultered fuel in your tank, it does not take a genius to figure out where the problem came from. Sheez.

Car started at the station without a problem, drove it 2 blocks to work, drove it 70 mi. total (3 starts, all difficult with sputtering and poor acceleration first mile or so) before tank flushed. Service and I didn't know about the diesel till I went to the station after the flush and was told about the contamination and where to send my expenses. Car was running fine but "Emissions Workshop" warning came on intermittently. Dealer said to bring it in at my convenience to turn off warning light. Drove another 3 days (about 150 mi.) before doing so, then dealer said catalytic converters and O2 sensors had to be replaced.

This sounds like a bad (destroyed) cat converter to me. Both from the way the car was driven before the fuel was replaced, and the way the MIL light came on afterward. Ask the dealer what code(s) were found when you went in for the final work.
I don't know where you are located, but here in California this would be a slam dunk in small claims court. IANAL, but you might also want to turn this in to your auto insurance policy, it should be covered under comp coverage, and their lawyers can then go after the fuel company.

[cornflakes]

Originally Posted by danceswithcats

Should VW allege that the exposure shortened the life of these components, then a urinating competition is likely to ensue. Good luck.

It already has ensued. The transport company is liable, but they're trying to minimize their expenses. Lindaak, I'll bet that they will pay when it becomes obvious that you are willing to go to court. They would rather pay the bill from the dealership than pay the bill, court assigned damages, court costs and their attorney's bill.

[mike1dog]

It seems to me that this would be a no-brainer. The diesel fuel was probably not being burned entirely in the combustion chamber and was being passed out into the catalytic converter where it was burning and overheating the converter and the oxygen sensors. I've actually seen cars do this that were just having a misfire. Converters don't like raw fuel of any kind.