What do I do after putting diesel in my tank?

We accidentally put 12 gall. of diesel into our 2002 toyota highlander. It stalled about a mile later. We towed it home and drained the gas tank. Now what? I have lots of Sea Foam that I use in all my gas for my small engines

How did you accidentlelly put 12 gall. of diesel in the tank?

How do you plan to dispose of this contaminated diesel fuel you drained ?

My son, who just got his license thursday, took a friend, who has no car or license, with him and his buddy could not get the other pumps to work, so he proceeded down the line to the diesel one. Trust me, this boy is a nice boy but far from the sharpest tool in the shed.
Ok, there you have it… Any advise would be appreciated. I own 2 Bicycle shops/not a car guy, but can usually fumble my way through it.


What brand of gas station was it a diesel pump should not fit in a gas tank? Thank you for telling us what happened we get quite a few poster’s on here with same problem & when asked how they did it not reply.

You know, I looked up Clems Gas Station 93422 and it does not say what brand gas it is. We think it is a 76 station. Should I just try putting a couple gallons of gas in it after I figure out what to drain it into, add some Sea Foam or some other additive?


Never heard of clems but did find a bp a while back that the diesel pump would fit in a gas tank. If it was me I would put at least 5 gall. or more along with sea foam and drive it for a while it may smoke for a while but clear up in time.

Ignore the additives. Put fresh gas in, hook a hose to fuel pressure test port and key the car to on, not start a few times to purge the fuel lines. Remove and try and start it. Should work. If not, the sparkplugs may be fouled. Replace them. If you want to add Sea Foam after it runs, go right ahead.

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Thanks, it worked. Took a bit of turning over to get it running but finally started. Smoked a bit during first drive. Sat in driveway for an hour or two then started right up but struggled until it warmed up. We’ll see where it goes from here. Seems like it might still be trying to burn off some diesel, so I am confident that it is on the mend.
Thanks again for the help,


Now you should make sure this new driver knows how to check oil , what the check engine light means , how to check tire pressure and just what fuel and octane go in the vehicle.

People force the diesel nozzle into the filler pipe all the time, it is only 1/16" larger than the gasoline nozzle. The large Diesel nozzle for commercial trucks is not used on the passenger vehicle pumps.

Yesterday we had a Lexus LC 500 in the shop with diesel in the tank, that is a $105,000 sports car. Wealthy people make the same mistakes as other people.

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Ok, he just drove the car 12 miles to a friends. Did not want to start for his drive home. It finally started and stayed running and he drove home. Now check engine light is on. ???
Thanks again for any advise.


Did you drain all of the fuel from the tank or most of it?

Keith, I’d guess this is a residual effect of the diesel. My Audi threw a couple of codes after running Sea Foam through the intake. I cleared them and all was OK. I’d suggest reading the codes and posting them here so we can advise. Auto parts stores will read them for free. In the form “P1234” please.

All fuel drained. Replaced with new fuel. Ran this morning and it seems to be running well. Smokey at first. Added some Sea Foam and ripped around town. Check engine light is still on. I have a neighbor with plug in diagnostic devise. Will check the check engine light problem after work today and let you know.