Old Petrol

[dhpaul]

I have just drained about 20 lites of unleaded petrol from my classic so I can do some extensive work on it. Now my question is can I use this petrol, which is 12 months old ? I was thinking of adding it to newly bought petrol in a Ford Focus, say 5 litres of "old" to 20 litres of "new". Does anyone have any thoughts on this, is it a good idea, should there be any problems?

[JPB]

There's every chance you'll get away with it mixed at that, but I'd strain it as it pours, just to take any obvious nasties out. It's almost certain to have gone off to some extent so expect a little pinking, or not depending on whither it reduces the fresh petrol's octane level to below that which the engine management can compensate for.
If it pinks badly, then reduce the amount you use in a fresh tankful to the point where it doesn't. Either way it will do no physical harm unless this is one of the new 1 litre, 3 cylinder Focii which, as suggested by the one I've just seen with its head off and a nicely holed piston, aren't as tolerant of poor fuel as older engines.

[Luxobarge]

I doubt it will pink in a Focus, the knock sensors will take care of that - it's what they are for.

Go for it, mixed as you suggest.

I use old petrol in the lawnmower, never had any problems.

[JPB]

They are, but take a look at the Ford service bulletins surrounding the 1 litre engines. They're weird and if the frequency shift is "outwith operating parameters" then the ECU is supposed to limp it in but clearly doesn't always do so, this is the second they'd had with the same piston having been holed and both cars had been collected roughly the same time after being filled at the forecourt of the same fuel supplier.
Weird little engines these, there's a belt where the timing chain should have been: Running in oil!
Only the French, etc.


I simply didn't want to suggest - unconditionally - that the o/p would get away with this if his car has this engine whereas the older, larger capacity ones will probably run just fine on something brewed in the woods.
Lawnmower comparison 2: I ran mine (a '60s Diesel-engined Allett whose original Reliant 850cc petrol motor was sold to be fitted to a trike) on a used engine oil/turps mix and that seemed to work. Free engine, tight owner, etc.

[Luxobarge]

You're telling me they do a 1-litre Focus???

[TerryG]

It's the new "ecoboost" version. I had one as a hire car a few weeks ago through work. To say the least it is RUBBISH! (slow, not as economical as my 2.0 diesel, slow, you have to rev it to the top of the range for it to move at all, slow, sounds awful, slow, as smooth as falling down stairs, slow, ermmmmm............ oh, and i think i forgot to mention, SLOW!)

[Richard Moss]

I was given a Rover 820 that had been standing unused for 3 years plus. After a jump start and a few seconds for the tappets to pump up it ran perfectly and drove perfectly.

[JPB]

You're telling me they do a 1-litre Focus???

Sorry to break it to you!
Terry, are you saying that the 1 litre Focus isn't very quick? Well that's shocked me I must say. That formula works pretty well in the VW Up, the Suzuki Alto and of course that class-leading classic performance vehicle the Fordson Super Dexta though admittedly the last has a 2.5 litre IL3, fuelled by Diesel so the Focus was always going to struggle to keep up with one of those.

I was given a Rover 820 that had been standing unused for 3 years plus. After a jump start and a few seconds for the tappets to pump up it ran perfectly and drove perfectly.

Did the same with a Series 1 Land Rover that had been standing in long grass for a decade or so. In the case of that one, we fitted a fresh set of points, a fully charged battery borrowed from the TK horsebox and then, first piston OTT, away she went and sounded as sweet as could be, albeit with some blue smoke that cleared once the rings had loosened themselves a little but that was in 1986 and that old fuel was leaded 2 star which tended not to deteriorate with standing around. Sadly, that old thing was only started so that the owners of the land could drive it out of its resting place and straight onto the scrapman's waiting recovery vehicle.

In your case with the modern (as in more modern than that S1 Landy and modern enough to have remained viable for production a good long while after it was killed off) Rover, I suspect that their engine management systems used more complex decay patterns as their data source rather than the A/F waveform sensor that does the job in that Focus and many other, cheaper and more modern engines simply by reading a single, 6.4KHz waveform from sensors that "listen" to the block. The former would theoretically be much more adept at coping with greater deviations in fuel quality as well as other relevant parameters where the simple audio sensor is by its very nature more restricted but - like many other things in more modern cars - cheaper to make and use and that would be great if cheaper equated to more reliable. Sadly, it doesn't and we see more and more modern engines - almost always the less conventional ones - suffering from faults that were present because designing them out would have cost an extra 0.07p per unit during the production engineer's meeting with the official holder of the purse strings!

[megadethmaniac]

ok so buy super unleaded and dilute that with the old fuel. small amounts at a time, I`d fill it up drive 30 miles and then top back up to full with the old fuel and I doubt that the car will notice any difference. And by dong that you probably wont`t either