I have searched the threads but apparently, no one else is as dumb as me. With everything else that is happening today, I went to COSTCO for gas and remembered to clean the screen of the gas pump, wrap the gas handle and then pumped 12 gallons of regular into my 2003 XK8. The car only has 13,800 total miles on it so it is a "low timer" in terms of wear and tear. What should I do if anything? What will happen, if anything? Does anyone else need me to fill their car for them? STUPID!

 

Just be sensible in the way you drive it until you can fill again. At least you didn't fill with diesel.

 

'Distracted filling', probably not the last time that happens in the near future. Your nearest auto store probably has some form of octane boost (or you could pour grain alcohol into the tank which is probably a waste of grain alcohol).

On the other hand, how much is it actually pinging (on the way home from COSTCO or otherwise)? Of course, I have three moderate mileage cars, but I'd probably just wait it out if I couldn't hear pinging or it was just occasionally (such as on full pedal).

 

Don't worry about it. Modern auto's have computers that automatically adjust the engine to meet the octane of the fuel used. It may not adjust it completely to the prescribed octane, but it will get it close enough that you wont know the difference if you drive the car in a reasonable manner. And if you are concerned, after driving for a period of time to allow the gas gage to come off full, then just add the higher octane to the tank. Do that a couple of times, then forget it and enjoy your Jag. At the next fill up, add the proper grade.

Chuck-----Of course I've never added the wrong fuel before. And if you believe that, I have a "Dead Cow" I'll sell you.

 

A different level of 'distraction' required with this one because of the need to shove the wide nozzle into the narrow hole. May want to check this driver for 'meth exposure', but reminded me of a 'Fifth Gear' episode...

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When I bought my used xkr off a lot, the dealer proudly proclaimed, "And we even filled the tank for you!"
You can guess where this is going.
It really took the wind out of that first drive.
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On the good side, Costo is a "top tier" gas station. Gas brands do not matter, the "top tier" does. it keeps everything clean and sparkly inside.

Just curious how much did you have to pay to get such a low mileage car? Did you take if to the shop and have them check all the rubber components?

 

How bad is regular gas in the US that you have to worry about using it?

 

Tis the octane rating, the tendency to incorrectly combust under typical petrol powered engine combustion/spark.

In the US, this is reported one way ((R+M)/2 for those who read pumps, also known as AKI, the antiknock index). In Europe, it is reported another way (RON, or the just the 'R' part of (R+M)/2)).

The numbers are not the same. Europe's octane numbers are about 4-6 higher for exactly the same formulation.

In any case, the engine was designed for fairly high octane, but, as noted above, has some capacity to deal with this. I'd be surprised, however, if there was not some pinging in the XK8/R on 'US Regular', usually 87 octane (91-92 in Europe) at high loads since it was designed for premium (93 in the US, ~97 in Europe). Probably inconsequential in the short term, and could be modified with a small decrease in performance, though maybe worse in the XKR.

So, 'regular' is good gas in the US, highly regulated as in Europe, but 'regular' is marginal for these engines.

 

Scott, Let me answer several comments in one post. I noticed no knocking at all after my mistake. Of course, I only put 11.? gallons in so it did mix with the older proper gas. I am not a spirited driver with this car and I noticed no real difference during my 25 mile drive home. I will mix in the correct gas as it starts to be consumed but, as you noticed from my mileage, I don't drive the car too much.

Now, as to the cost it was entirely too much! The car is perfect and appeared to have not been driven at all. It was more than a 10 and it had every possible option that was offered in 2003. I have a tendency to collect cars with extremely low mileage and this one only had 12,000 when I got it. Never-the-less, I paid $21K which was probably $6,000 too much.

I also have a 2010 Aston Martin that came with 14,000 miles on it and was also perfect in every way. In that case, I did really well, as I bought it from the AM dealer in San Diego, and they are nothing short of AMAZING. I have put 400 miles on it in the year that I have owned it so it does not get driven much. But WOW, what a car!

I have a 1975 MGB with 4,500 miles on it that I have owned it for about 35 years. It did spend some time in my airplane hanger so it was not driven much. I had a Delorean that came with 6,500 miles and belonged to John's wife! I also have a 2015 Corvette that I bought new and it only has 1,800 miles.

In short, I always buy new for my drivers.....Lexus and Audi but the toy's are normally low mileage "finds" with the exception of the Corvette which was made to order at the factory in 2015.

 

Holy Cow! This is what will HAPPEN! - nothing- you may suffer a slight decrease in mileage. My wife drove mine
for a year and right when I took back “my” car from her we were at the gas station- you can guess the conversation from there.
She had always used lowest octane she could find. Never an issue and she has a heavy foot.

 

scott,

a thought/ question comes to mind...methanol seperation...it can take as little as 3 months for fuel to separate when sitting...it will also draw moisture out of the air and settle to the bottom of a tank...(more frequently in boats on the water)...so, what do you do as a preventative ? be aware it can cause severe engine damage when it gets sucked up into the engine.
suggestions: 1) octane booster for the xk 2) seafoam "motor treatment"/ stabil 360..etc... IN ABUNDANCE for all your cars...you cannot use these too excessively in any gas engine.
you will likely be surprised in a performance increase as they, additionally, clean your injectors/ carbs and internal engine (valves, chambers).

ps... i covet thy collection ;-)

max & XKRFACE

 

exscussa.... ethenol....

max