Dealership discovered lots of oil and gunk in the gasoline in my G70. WHAAT?

[tarhoosier]

Has anyone identified the "oil"? Fuel oil? Motor oil? Two cycle engine oil? The identification of the infecting liquid would be the key item.

 

[Purple Ray]

No, of course not. Gasoline is lighter than both diesel and oil. Any of either that got into your gas tank would be pretty quickly pumped into the engine, since it would be sitting in the bottom of the tank, where the fuel pickup is. I'm surprised that it took half a tank to happen (assuming that you filled up completely). Of course gas stations can and do sometimes get cross contaminated. It happens when the guy refilling the tanks at the station is careless and and starts pumping into the wrong tank.
Your case is really odd, since apparently no one else experienced problems with this. That's unlikely, but not impossible.

My understanding of gas tank design is that the line out of the tank isn't at the bottom of the tank. This is to avoid pumping into the fuel line any contaminants that make it into the gas tank. As a result, a certain amount or diesel can sit in the bottom of the tank for a while, and at some point there's a "tipping point" (this might be literal?) where the accumulating diesel could enter the tank. I'm assuming here that my gas station continually receives gas that is contaminated and I pump it.

Even crazier is part 2 of this story, that I haven't shared yet. To summarize briefly part 1 -- the evening before the car was towed, there were several moments of hesitation interspersed with normal driving, then the next morning the car "bucked" or lurched horribly, causing me to have the car towed..... and then here's part 2: the next day the service technician took the car out for a spin and couldn't find anything wrong with it. NOTHING. He took it out 2 days later and the car "hopped all over the place" before he got it out of the dealership parking lot. I'm assuming diesel got into the fuel line, had bad effects, then for a while DIDN'T get into the line, for a while, and then it did. The hills encountered were pretty minor, in case this matters.

Any new thoughts on this?

 

[Purple Ray]

Has anyone identified the "oil"? Fuel oil? Motor oil? Two cycle engine oil? The identification of the infecting liquid would be the key item.

I've asked that when the tank is drained, as sample with the "gunk" is saved for me so I can take it somewhere (have no idea where yet) for testing. (The special investigator sent by my insurance company said "diesel" and the repair estimate said the same, but I think that's just an assumption.)

 

[joegr]

My understanding of gas tank design is that the line out of the tank isn't at the bottom of the tank. ....

Well, I haven't opened up the gas tank on a Genesis, but I have replaced fuel pumps on other cars, including a Hyundai Sonata, and on all of those cars, the fuel pickup(s) were all at the lowest part of the gas tank. (Some of the cars had saddle shaped tanks that had a pickup (and pump) at the low spot on each side.) I don't know why you would want a tank that held gasoline that you could never use. In the absence of some proof, I will continue to believe that the pickup is at the bottom of the tank.

BTW, the fuel line(s) does not come out of the bottom of the tank, it comes out the top or the side (almost always the top now), but the fuel pickup sock inside is at the bottom. The sock keeps trash from being pulled in, but liquid goes through.

 

[Purple Ray]

Well, I haven't opened up the gas tank on a Genesis, but I have replaced fuel pumps on other cars, including a Hyundai Sonata, and on all of those cars, the fuel pickup(s) were all at the lowest part of the gas tank. (Some of the cars had saddle shaped tanks that had a pickup (and pump) at the low spot on each side.) I don't know why you would want a tank that held gasoline that you could never use. In the absence of some proof, I will continue to believe that the pickup is at the bottom of the tank.

BTW, the fuel line(s) does not come out of the bottom of the tank, it comes out the top or the side (almost always the top now), but the fuel pickup sock inside is at the bottom. The sock keeps trash from being pulled in, but liquid goes through.

Thanks, Joegr, for the lesson on gas tanks! I didn't know about the filtering "sock." I do wish the sock could filter out oil. So as an additional question, wouldn't the filtering-sock eventually get all clogged up and need cleaning or replacement so that gas could travel through the fuel line? And would the presence of the trash in the pumped gas mean that the tank at the gas station was almost empty and therefore customers were getting trashy (a.k.a. contaminated?) gas?

 

[joegr]

Thanks, Joegr, for the lesson on gas tanks! I didn't know about the filtering "sock." I do wish the sock could filter out oil. So as an additional question, wouldn't the filtering-sock eventually get all clogged up and need cleaning or replacement so that gas could travel through the fuel line? And would the presence of the trash in the pumped gas mean that the tank at the gas station was almost empty and therefore customers were getting trashy (a.k.a. contaminated?) gas?

I can only say that I have never seen the sock get clogged. They look pretty clean after 250K miles, as do the gas tanks themselves.

 

[Purple Ray]

I can only say that I have never seen the sock get clogged. They look pretty clean after 250K miles, as do the gas tanks themselves.

Thanks again. I am mystified. I had the gas station checked for contaminants (by a state agency) and there were none. Zero. And that includes oils.

Call me crazy, but I think the contamination of the gas came from the car. Could a leaky valve cover gasket (or more than one) over time allow oil into the gas? Or something else in that vein of thinking?

 

[pulsar]

My money is on bad fuel from somewhere that got put into the tank. I have heard of leaking head gaskets get antifreeze contaminated in the oil and you can see that on the dip stick, but never heard of something making its way back to the fuel tank itself. Not saying it’s not possible, just not something I have seen before. Heard plenty of cases where bad fuel induced into the tank caused an issue though. Finding and proving who the culprit was is always the biggest issue.

 

[Purple Ray]

My money is on bad fuel from somewhere that got put into the tank. I have heard of leaking head gaskets get antifreeze contaminated in the oil and you can see that on the dip stick, but never heard of something making its way back to the fuel tank itself. Not saying it’s not possible, just not something I have seen before. Heard plenty of cases where bad fuel induced into the tank caused an issue though. Finding and proving who the culprit was is always the biggest issue.

What you're saying makes sense to me, but I know I didn't do it and no one else has access to my car. And it's a stretch that in a nice neighborhood there would be someone prowling around looking for an accessible gas tank to dump oil into, and then follow through with it. And I think if someone did that to one car he would do it to others, and I'm not seeing any posts like mine on my very active Next Door thread. That's why I'm posing improbably theories.

(As an aside, what is your best guess as to how far in advance of the symptoms such an event might have occurred, given that the tank was half empty?)

 

[SuperKing]

Thanks again. I am mystified. I had the gas station checked for contaminants (by a state agency) and there were none. Zero. And that includes oils.

Call me crazy, but I think the contamination of the gas came from the car. Could a leaky valve cover gasket (or more than one) over time allow oil into the gas? Or something else in that vein of thinking?

A leaky valve cover gasket would just leak oil out of the engine and drip down the side.

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[Purple Ray]

SuperKing -- I just mean we need to think out of the box in order to find the source for the oil. Hopefully the thousands of dollars now being spent on replacing parts will remedy whatever the problem is/was.

The source of the issue likely wasn't the gas station I used (they don't sell diesel and tested zero for contaminants) and likely wasn't a vandal finding my car unlocked and choosing to pour oil into the gas tank (this is mighty far-fetched). I do welcome other theories!

 

[SuperKing]

Sorry but Occam's Razor applies here. The simplest explanation is the best one... there's only 2 ways into the fuel tank. Either through the fuel line or through the fuel filler. It's impossible to fight the thousands of PSI of the fuel injectors to come through the fuel line and fight gravity to make it up the fuel pump into the tank. The only way it could've got in there is through the fuel filler.

 

[007IOU]

Sorry but Occam's Razor applies here. The simplest explanation is the best one... there's only 2 ways into the fuel tank. Either through the fuel line or through the fuel filler. It's impossible to fight the thousands of PSI of the fuel injectors to come through the fuel line and fight gravity to make it up the fuel pump into the tank. The only way it could've got in there is through the fuel filler.

+1

 

[BadTrainDriver]

Let's stop and think for a second; what proof do we have that oil was actually in the gas tank besides what the dealership told him?

OP, do you have proof? Pictures you can post? What?

 

[5.0KDM]

Did you add any additives to the tank?

 

[joegr]

SuperKing -- I just mean we need to think out of the box in order to find the source for the oil. ...

That's fine, but there's just physically no way that the oil (if it was oil) came from anywhere, anything else on or in your car. If there was oil there, it got there via the filler tube. The only other (very very remote) possibility would be the fuel tank vapor system. So many different parts of that system would have to fail to allow even a tiny bit of oil vapor to travel the wrong way, that it is impossible for it happen, let alone for the failures not to be found.
It went in the filler, or it didn't happen at all and the dealership is crazy.

 

[csu87]

SuperKing -- I just mean we need to think out of the box in order to find the source for the oil. Hopefully the thousands of dollars now being spent on replacing parts will remedy whatever the problem is/was.

The source of the issue likely wasn't the gas station I used (they don't sell diesel and tested zero for contaminants) and likely wasn't a vandal finding my car unlocked and choosing to pour oil into the gas tank (this is mighty far-fetched). I do welcome other theories!

like others have said, there is virtually no way for oil to get from your engine back to the tank unless you have massive failures in various other systems in the car. (like your fuel pumps failing and causing some sort of vacuum that sucks oil all the way back to the tank past the various filters.

it was put in to your tank, either deliberately by someone being a dick or by you on accident

 

[tarhoosier]

Let's stop and think for a second; what proof do we have that oil was actually in the gas tank besides what the dealership told him?

OP, do you have proof? Pictures you can post? What?

Earlier in my driving history I was on the road hundreds of miles from home in my VW. My car engine stopped on the interstate and I coasted to a stop. What could it be? I hiked to a phone location and called a tow. It went to a VW dealer who spent fifteen minutes examining and said it was major mechanical failure. While the teardown began I called a motel and then walked back to service. I saw my car on lift and asked mechanic what he saw. He said there was a fuel line displaced but he was told by advisor to remove all parts to prepare for an engine rebuild. I said STOP! Within 30 minutes I was on the road. My out of state license on the car while on flatbed may have been the license for theft by this facility.

 

[BadTrainDriver]

Earlier in my driving history I was on the road hundreds of miles from home in my VW. My car engine stopped on the interstate and I coasted to a stop. What could it be? I hiked to a phone location and called a tow. It went to a VW dealer who spent fifteen minutes examining and said it was major mechanical failure. While the teardown began I called a motel and then walked back to service. I saw my car on lift and asked mechanic what he saw. He said there was a fuel line displaced but he was told by advisor to remove all parts to prepare for an engine rebuild. I said STOP! Within 30 minutes I was on the road. My out of state license on the car while on flatbed may have been the license for theft by this facility.

That makes me sick to read, being in the automotive repair business. I have a little thing called a conscience...

 

[BadTrainDriver]

OP, is this a "customer pay" ticket? Meaning, are you paying the bill? If so, you need to have proof of what the issue is.