To say No (DP put petrol instead of diesel in car)

[NotAHousewifeFromCheshire]

DP has just phoned from Gatwick where he is picking up 1 of his DC . His DD (18) is with him.
He has broken down which has now transpired he has put petrol in the car instead of diesel.
He is obviously off the scale pissed off & suggested I should come to collect them (via Uber) so they don’t have to wait.
The journey is 45 minutes each way.

I don’t have the money to spend.

AIBU to say no ?

I'm shocked at the prices for draining the fuel tank on here. Both my father and mother in law have done in this- petrol in a diesel. Our local garage charged them £30 to drain and clean the tank and engine. Maybe it's because they always do all our family cars, MOT's, repairs etc that it's cheaper? But the prices quoted here have been an eye opener.

I can understand him panicking a little, if dc had a 6 hour flight, they've probably been hanging around airports and travelling 12+ hours, he probably just wanted to get them home. I think the sensible thing would have been to say I'm getting the dc an uber home whilst I wait. I don't understand the you getting in one and doubling the cost of the journey? I don't really see what you could have done except phone for recovery like you did?

I don't know why the pumps and filler pipes are set up to prevent the opposite. If they made the diesel holes smaller and the petrol nozzles bigger, this would prevent the 'worse' mistake from being made.

The reason why petrol nozzles are smaller is that when leaded and unleaded fuel were both available, and diesel cars were relatively rare, cars which required unleaded fuel had smaller fillers to prevent leaded fuel being put into cars with catalytic convertors. Unleaded fuel in a car which needs leaded won't do any harm in small amounts: if your car has run on leaded since forever and you put one tank of unleaded in it, then it will either do no damage or do damage so minor it is unlikely to matter over the lifetime of the car. Conversely, if you put leaded fuel in a car with a catalytic convertor, it will rapidly kill the catalyst. Hence the filler size: unleaded fuel was served from smaller nozzles, cars with catalysts had smaller fillers.

Eighteen years or so after the last tank of four star was pumped, we could use different nozzle sizes for other purposes. But we can't, because there are a lot of cars (ie, for practical purposes, all petrol-engined cars made in the last 25 years) with smaller filler holes, which petrol pumps have to fit.

Well I don't class myself as a dickhead, think i am a rather nice well balanced person but I admit I have the tendency to not always pay close attention and to do things out of habit.
I have put Unleaded fuel into my diesel engine - not just once but twice!
The first time I didn't even know I had done it. I filled car up at my parents and drove 60miles home, admittedly thinking the car wasn't running quite right but it got me home, 3 days later it was in for a service and I got a phone call telling me it had been misfueled - something I emphatically denied until i found my garage receipt and then i couldn't deny it. Because the car had driven it had speed the fuel throughout the engine and the garage refused to let me have it back until i had arranged it to be corrected at a quote of £4-5,000 However my car insurance covered it as the car was deemed to be of sufficient value to warrant paying for the replacement engine, the excess cost us £200.
I was scared every time I put fuel in for a few months checking and double checking until I was talking to DH as I got out at local garage and just put the fuel in.......£7 of unleaded in when I realised my error - I was mortified, DH was not impressed at all but the cashier gave him a phone number of a rescue service to come and 'sort it'. 2hours later the tank had been drained and we were £180 lighter. The rescue guy also sold us a device that sounds an alarm when the fuel cap is opened, and trust me it works!!
Bother rescue guy and the cashier told me it happens several times a week - who knew so many 'dickheads' were about

@Ivebeenaroundtheblock

The two nozzles are angled differently. And different diameters.

Well yes, the different diameter is key. As i said above, i can see how one is smaller than the other, but not how the diameter (and angle) can prevent unleaded being pumped into a diesel. Still waiting fir the explanation....

I believe you can put up to about 10 percent unleaded into diesel but it is not a good idea as it is then getting a bit 'thin' to keep the injector pump lubricated properly.
OP's DP didn't really NEED Uber or whatever but with the mad panic of a 'failed' car and responsibilities to the younger ones another brain to help come up with a 'best' plan was probably necessary.
I would have gone out to my DP if necessary, but after a discussion of a plan.

After a million nosey parker questions from me
the man who drained my husbands tank told us that they sell the fuel on. Can't remember the arrangement or who buys it.

If you had spotted you were putting unleaded in with only say 10 Litres you could just fill the remaining with diesel and get away with it.