Before panicking, try to determine whether this actually happened, or might the engine just be misbehaving ? What colour was the hose that you put into the tank, green (petrol) or black (diesel) ? If you can't remember, take off the filler-cap and sniff (hopefully you can tell the difference) :-)

Adding correct fuel without draining the wrong stuff would be a 'dirty' solution but might be enough. By the way, you should put fuel into the tank, not the engine .... :-)

More info needed to weigh up pros and cons of this gamble. Age? Mileage? Current diesel petrol ratio in tank? From the info there could have been 1 gallon of diesel left - now has an additional circa 3 gallons of petrol (I still think in old units). There is a slight tendency for petrol to float on top of diesel, so there may have been sufficient lubrication for the fuel system to avoid terminal damage on the way home. Personally, I wouldn't gamble just adding diesel, I would remove as much fuel as possible first. If syphoning is impossible I would jack it up on blocks and look for a fuel pipe connexion to undo and drain off as much as possible before adding diesel.

Do you still have the receipt from the petrol station? It will show what you purchased, petrol or diesel.

I have done this with a diesel Renault Clio and, after agonising for a bit, just topped it off with more diesel, but I think it was about 20-25% petrol, perhaps a more favorable proportion, and, critically, it was a HIRE CAR.

No apparent problem over the following quick Highland tour, though they seemed to spend a long time looking at it when I brought it back

If I had been in Taiwan, where its still widely available, I'd have also chucked a bottle of 2-stroke oil in the tank. I considered using motor oil but decided not to, though on a nonDFP engine (I don't know if this was, though I suppose I could work it out from the date) this would probably have been worth doing.

On my own car with 75% petrol I would drain the tank for sure.

By contrast, when I put diesel in the tank of MY Nissan Sunny, I got a tow home and drained the tank, which had a drain plug.

Edited by edlithgow on 13/02/2022 at 23:31