How long does diesel fuel last before going bad

[chris72a]

Hey all, just curious as I havn't driven van for at least 4 months (maybe more) due to various reasons, anyway after replacing batteries and taking it for a drive it has an awful knock on start I was told by a diesel mechanic friend that it is probably the diesel gone bad and to drain the tank and put some fresh diesel in, Does this make sense, not much expertise here on the diesels.

Many Thanks
Chris.

[dumper]

I have worked n the construction plant industry and have had plant stud for over a year a and not had problems all we have done is make sure the tank is full to stop condensation in the tank to stop water build up I don't think it goes off like petroll

[DodgeRover]

Modern fuel does go off (due to the biodiesel content I think) I've seen black clumps in a full sealed clean drum that was stood for a year after filling from the pump when I went to get it.
That said it should still be ok after 4 months, if it hasn't got much in I would top the tank off with new stuff and throw a tin of injector cleaner in with it.

Is this one if the engines with a timing solenoid that fails? That makes them noisy.

[dozybee]

My Luton spends most of it's life as an office. The last fillup was April 2014. It starts/runs fine as of today.
I had better dip the tank and see what is lurking within. Any suggestions about biocides for diesel?

[DodgeRover]

Look up biocides and fuel stabilisers they do a lot for boats where it's supposed to be more of a problem, mind I've never seen cherry go off and we've put some very old stuff through the tractors.

[mclacr]

It grows a fungus if left. also water can condense on the tank walls and run to the bottom of the tank.

[DIESEL SAM]

Heard this from a diesel engineer friend if yo store fuel for a long time is to add a drop of JAYES FLUID to it and it stops it growing fungus !!