Dear Doc,

This might seem like an odd question, but does diesel go off? Stupidly, I filled my CR-V with diesel just before the lockdown was introduced and the car has been off the road ever since. By the time the lockdown has been lifted, it could be three or four months of inactivity for the car.

My wife says it will be fine, but I’m sure I remember you saying something about shelf life and not storing diesel for a long period of time.

Please let me know – there’s no rush!

Cheers,

Mick Jones

Hello Mick,

You have a good memory. I’ve searched my records, but I can’t find a response about fuel, which suggests it stems from the days when I was using a quill.

It’s not an odd question. Given the price of oil, I’m tempted to buy an old tanker and store a load of diesel in the garden. Sadly, I don’t think my wife would be too keen on the idea.

Anyway, I understand your concerns about the 58 litres of diesel sitting in your Honda’s tank, not least because you would have filled up before the prices plummeted. There’s no need to worry just yet. Diesel can sit in the tank for up to a year without a problem, so it’s not going to go off. Petrol has a shorter shelf life of up to six months.

After a year, the diesel has the potential to clog filters and cause damage to the engine, so I definitely wouldn’t recommend using it then. In the meantime, I’d suggest running the car for about 20 minutes every fortnight, just to keep the battery topped up and the engine working. I’d also suggest moving the car a few inches, but I’d refer you to my response to Max, which I’ll attach to this email to save you waiting for the magazine.

As an aside, did you know that it’s illegal to store more than 30 litres of petrol at home, but there are no restrictions when it comes to diesel? Maybe that diesel tanker idea isn’t so bad after all.

Stay safe and enjoy using that CR-V when the lockdown is lifted.

Kind Regards,

Doc