How bad is this?

My sister accidentally put some diesel in the gas tank of her Jeep Liberty. Probably about 3-4 gallons in an approximately 16 gallon tank. I asked a friend who is a fairly knowledgeable mechanic and his thought was that it should be ok and to keep adding gasoline to keep it diluted and keep driving it. We drove it about 70 miles today and it seems ok. It had originally triggered the CEL, it was some misfire codes. I cleared them and we drove about 30 miles and the CEL stayed off. She heads home tomorrow, 300 miles, and I now have second thoughts about sending her on her way. Will the gas dilute the diesel and eventually get rid of it all or should I have her get the tank drained. Mostly worried the diesel will settle the the bottom and be more likely to get sucked into the fuel system and really clog things up.

So I typed out some advice and then realized that it was based purely on conjecture and not on any real knowledge. My guess is that if it works now, it will continue to work. If it were me, and it was working now, I'd fill it all the way up, drive it 150 miles in circles tonight (what are brothers for after all) and then fill it back up and send her home. Does she have AAA? She should have AAA.

Thanks, she does have AAA and I feel like if it was going to be catastrophic something would have happened by now. I guess time will tell

It won't hurt it.  Burn as some gas and replace it with gas to dilute the diesel, and it'll be fine.  It's relatively bad if you do the reverse (gas in a diesel), because gas isn't slippery enough for the fuel pump and injectors, but the other way around isn't very bad for the car.

that and diesel uses compression for combustion, gasoline in a diesel engine causes knock because it bursts into flame way too fast.

A few gallons of Diesel in a gasoline engine will not harm anything as long as it starts.

Thanks for the reassurance that she should be ok. Will feel better when she gets home with no drama. She manages to turn the simplest things into an adventure. Happy Thanksgiving to all. Thanks again for your help.

The diesel hose nozzle is physically larger than the gasoline hose nozzle.  This is intended so you can not put diesel in a gasoline tanked car.  This leads me to wonder, did she really put diesel in the tank or just think she did?  Did she physically move the car to get to a non-diesel pump?

Below we have a single pump station that pumps Unleaded Gasoline, Unleaded Plus Gasoline and Diesel.  That is 2 types of Gasoline and 1 kind of Diesel. Someone who is "non-car-guy" could mistake that this pump only sends out 3 kinds of Diesel.  What they might see is Standard Diesel, Unleaded Diesel and Unleaded Plus Diesel.  

Is it possible that she really did not pump in Diesel?  

Ask her what made her realize it was diesel?  Was that reason because the nozzle would not fit in the opening or did she see the sign after the handle/nozzle was properly in place?  If that hose/nozzle was properly in place, it was not Diesel.  

Also ask how much Diesel she got on her clothes.  Trying to pump fuel from the large nozzle into a small nozzle opening will surely get a surprise splash back resulting in some fuel on your clothes.  

Sample video of the different nozzle sizes...

https://www.youtube.com/watch?v=d_2IXEmpEZc

She had a a difficult time getting the nozzle in so fought with it for a while before giving up and then realized what she had done when hanging the handle back up. It was one of the set ups with two hoses, one for diesel and one for gas. A poor end to a very long and trying day for her, all in all she came out ok.

Well, that sounds like she got Diesel.  She had to work pretty hard at it.   

Tell her the "car-guys" say to remind her that this isn't high school.  Don't just ram the hose until it fits.  

Not sure how she got it in there, but if you keep diluting it, it should be fine.

Most pour in fuel cleaners have diesel in them. Dont be surprised if it runs better or gets a little better fuel economy once you run it all through there.

I knew a guy who used to use diesel in a gas motor when he got a cat code. Said it had about a 25 percent sucess rate. If the failure was caused by broken matrix obviously it wouldn't help, but an efficiency code from burning oil or coolant could be remedied.

If it starts and runs, it will be fine.  Don't push it too hard, because the octane rating has gone way down.  If you don't have codes, not to worry.

My sister put diesel in her Beetle in the late 70’s.  She easily diluted it out over time.  

In reply to Streetwiseguy :

I don’t have any experience with diesel, but I’d think the octane would go the other way (wouldn’t it?)

Not all diesel pumps have bigger nozzles, just typically the truck pumps.  

LanEvo said:

In reply to Streetwiseguy :

I don’t have any experience with diesel, but I’d think the octane would go the other way (wouldn’t it?)

Octane for diesel is something like 20.

As the others have said, just keep diluting it and it will be okay.

Diesel has a very low octane rating but it also doesn't vaporize and ignite nearly as well as gasoline (if at all).  Gasoline engines that have been filled with Diesel or kerosene generally don't want to start.  So if the engine runs acceptably well with no cold-start issues, you'll be Just Fine.  If you're paranoid, top off with 93 or whatever is highest in your area, to combat the octane dilution.  Then run the tank as low as you dare before you refill again.

Dump in a can of seafoam for good measure,I had a friend that would use  some highway diesel occasionally just to keep things slippery.

I would've preferred to drain the tank over that much diesel, but you can get away with it. Add lots of octane booster and keep topping it up.

In reply to GameboyRMH :

Octane booster is mostly a wallet draining device.  When they say it adds "four points", what that means is takes you from 91 to 91.4.  No sense in bothering.

^Depends, I used to mix up some octane booster composed mainly of a healthy amount of xylene that made a big difference and was fairly cheap!

A more cost-effective solution might be to just top up with the highest octane available, ideally add some ethanol in the highest proportion the engine can handle.

Could be worse. Could have put gas in a diesel. 

I accidently dumped a few gallons of kerosene into a Chrysler once.  Diluted it with "High Test".   I had to use a light foot for awhile.

Did she make it home? 

So it turns out you can mix a little diesel into your gas and not ruin your engine. Heard from her an hour ago. She made it home with no problems, the CEL even stayed off. Hopefully she learned a good lesson, but she is a free spirit who seems to be able to make an adventure out of the simplest of tasks. Thanks for the support.