Comment by kotaKat
> I reckon it'll be more than fine for older diesel engines
There's always the risk of getting your fuel tank dipped if you're on road. Moreso for trucks, but some jurisdictions will set up inspections and check for dyed fuel and tear you an absolute new one when they catch it.
The exit of off road events is a common place to check this. So much so that there is a reputation in the off road community and now they don't even need to check often anymore since nobody is stupid enough to risk driving a truck that has ever had off road fuel in it there.