I am in the hunt for a used second gen justa for my teenage daughter. I'm trying to avoid the N12 engines and she has her heart set on Horizon Blue, so that is forcing me to the 2011's.

I have seen several that are in the 60 - 100K mileage range. Driving one of them, I noticed that the gas cap suggested 89 octane. Most pumps in my area have either 87 or 93 with the 93 generally being .40 more per gallon. Given these conditions, I would bet that there is a high likelihood that a prior owner would pump the 87.

I have read up on the issues with octane and I always put "top tier" 93 in my S. What I'm curious about is the damages that could occur to an engine over tens of thousands of miles running low octane fuel. I know the ECU will adjust to the lower octane and the prior owner didn't notice an issue and thought it was fine and kept putting it in to save some cash.

Are there any telltale signs to look for that show a lower octane had been run? Is this really a concern? Could something explode on it down the road even after feeding it the proper fuel?

 

Shouldn't be an issue unless the fuel is really low octane. The ECU receives input from the knock sensor and retards the ignition timing. No harm done.

 

agree

 

Get a qualified PPI done to eliminate those and other concerns.

 

From experience learned the hard way, not using Top Tier fuel will eventually terminate the knock sensor. Make sure she understands that.
http://www.toptiergas.com/

 

Hi Minnie,

I do plan on having the PPI done before purchasing. We test drove one a week or so ago and had a PPI done on it at a MINI dealership. They found issues that would be obvious through external visual inspection, like a leaking front main seal and water pump. But nothing on their checklist would give any sense of how the engine was running. This was in a state without emissions inspections.

Since I'll be flying up to the state where the cars are (I have a business trip), it isn't practical for me to bring any tools along with me. Otherwise, I'd pull the plugs and have a look as well as take a crawl under the car.

The cars I am interested in are in a state that requires emissions testing. Would the MINI dealership do a different type of inspection in this case? What would I ask them to do to get a better sense of the internal health of the engine?

Thanks for your advice.

 

I am curious what you have against the N12 motor? I have a 08 base with a N12 I purchased in Aug of 15 with 120k on it and now has 156k running great on 87 octane I drive it about 450 miles a week with no issues.

 

Hey Scott,

I'm not dead set against the N12 nor the N14 for that matter. This will be for my daughter who will be heading hundreds of miles off to school soon. From reading this forum, I have gathered that the N12 is less problem prone than the N14 and the N16/18's have been better with some of the issues that plagued the earlier engines. I may be affected by "forum paranoia", though.

I'm happy to hear yours has been good to you. I certainly hope you can get another 100K out of it.