Intention is for this car to be a high mileage highway commuter (I'd like it to put out another 100k kms of relatively reliable use) - it's a '07 Justa and pre purchase research led me to believe the N12 was less problematic than the N14. I'm hoping a recent (contra)indication can be easily solved.

I have(and prior to purchase) searched the forums for N12 oil consumption/low oil pressure threads - they inevitably digress into N14 discussions without a lot of insight on N12 issues (PLEASE take that as a request to adhere to N12 pertinent commentary in this thread, even though there aren't a lot of them - thanks).

Scenario - topped up oil at work Saturday night using BMW full synthetic (roughly 300ml to bring it to the full mark). Picked up the missus Sunday morning, drove to the airport and at the last traffic light before the parking area experienced the 'low oil pressure' warning light (red dripping oil can) when at idle. Virtually as soon as it appeared, I gave it a brief throttle blip and it just as quickly disappeared (and did not reappear again up to the time I shut the engine off).....we are enjoying Vegas for a couple days, but my idyllic time here is being undermined by the niggling feeling that the warning light is just the beginning of some serious Mini health issues.....I have, in fact, spent hours tracking Vacuum pump threads, PCV threads (hard to imagine), oil filter threads, oil pump threads and ANY specific N12 threads I can find.

I guess I'm hoping someone can chime in with insight that will allow me to enjoy the next few days before I return home to see what is actually going on.....

 

Am assuming there is an oil pressure sensor in there someplace. How many miles on the engine?

 

Sorry, meant to include that detail .... ~129,000 kilometres or 80,000ish miles. Oil pressure sensor exists and was replaced by previous owner, as was the timing chain tensioner.

 

Are you losing coolant? Could be different, but I had a similar situation with a bike that showed low oil pressure light at idle when I throttled up it would disappear. Took me a while to figure out there was coolant plugging up the oil filter reducing pressure. The problem would go away when I changed the oil only to return a short time later... Do an oil change see if you can't see any coolant in the oil. You can also inspect the filter and see if it looks distorted.

 

An oil pressure issue could be a number of things, a failing oil pump creating low pressure at idle as these cars don't have oil "level" sensors. It sounds like the previous owner had the exact same problem and replaced the oil pressure switch and I seriously doubt any car could go through two of them in 80,000 miles. I believe something else is going on, did the previous owner say when he replaced the oil pressure switch and did you check your oil at the time your oil pressure light lit up?

 

Yes, previous owner replaced oil pressure sensor switch, and, no I did not check oil immediately after getting the low pressure warning (I had literally topped off the oil less than 20 miles earlier AND we were in a time crunch to catch our flight), however, oil level and coolant levels will be the first things I check upon arrival back in Calgary. My gut says failing oil pump, but it hasn't been a frequent occurrence that I can tell.......

 

Let us know the result of your findings. I've never seen an oil pump fail in my life. Ever. The gear lobes are chain driven off the crank and don't even touch. A pump failure would be pretty shocking to me, just sayin. If your slowly leaking coolant into the system it won't show any symptoms until the filter decides it's time.

 

You might try using something like Liqui-Moly Engine Detox or BG Engine Performance Restoration to clean out the oil channels that could be clogged or restricted. I also recommend Mini oil filters as I've heard those cheap filters falling apart clogging up the oil channels, this isn't the first time I heard of oil pumps failing in non-turbo and turbo Mini's. Nothing is immune to failure, there's a first time for everything.

 

No oil in coolant, no coolant in oil, no leaks (and completely dry underneath), oil is at full mark as topped up on Saturday. Can add more symptoms: does NOT happen when motor is cool, but does once warmed up and ONLY happens when < 1500 rpm (raise rpm above that and it goes away). Now thinking it may be a grounding issue....

 

That just means that your oil is low on pressure below 1500 rpms which could indicate a weak pump, clogged channels or another bad oil sending unit. I would expect that a failing oil pump would exhibit problems at low rpms rather than high rpms as the pump is driven off the crankshaft.

 

Well, I'd buy that if the same indications occurred when the engine and oil were not at operating temps - given that this doesn't happen until up to temperature (despite viscosity changes) I'm not buying it.

Further narrowing of symptoms: actually occurs only < 1000 rpm AND doesn't happen while driving an already warm car that was turned off and then restarted a few minutes later, although it does recur after some (unknown currently) duration of driving. Hooked up my code reader = 'No DTCs Present'

 

Sometimes it's hard to see, did you do an oil change? That would be the easiest first test. If a new filter doesn't change anything I would have to guess electrical like u say.

 

Oil change will happen Saturday. More researching indicates the symptoms I'm experiencing are similar to what the first gens went through when the oil bypass valve popped out of position inside the oil filter housing......at this point I don't even know if my N12 motor HAS the same bypass valve that was used in the previous model iterations. I'm sure someone here can tell me......?

Also, if I'm keeping this thing, what service manual is recommended? I'm gonna guess Bentley, but again, somebody here is going to KNOW......

 

It states in my Bentley Manual if tests show low oil pressure, indicates a worm or faulty oil pump or faulty pressure relief valve. Test oil pressure by removing oil pressure switch and installing oil pressure gauge in its place. It also says if red light is flashing indicating low oil pressure assume that oil pressure is low, stop engine and immediately make arrangements to test oil pressure.

The valve-train is first inline to suffer damage from low oil pressure and or low oil levels especially while sitting at a red light minutes on end, having plenty of oil in the crankcase isn't enough. If you must drive then I would suggest you rev it whenever stationary. The Bentley Manual is the one to get for sure, there is the older version and the newer updated version. Get the updated version if you can.

 

Roger to all that - thanks.

 

Well, oil change and a new BMW/Mini filter appears to have solved it .

If I was to guess - I'd suggest it was an aftermarket filter causing the issue. I pulled 4L of used oil that wasn't 'clean', but it also didn't look horrible by any means. We'll see what happens over the next few weeks and few thousand kilometres....

I'll update again here if it reappears.

 

That's what I thought...I'd bet you have a slow coolant leak into the oil system, theres no reason any filter would have flow problems unless it's getting soaked with water. When coolant passes through the filter it blocks it up. If it's a slow leak it may take a while.

When I had this problem on a bike you couldn't see any coolant in the oil at all the only way to tell was that the filter looked slightly distorted.

Keep checking your coolant level. Prolly needs a head gasket or something. This problem should resurface, if it gets fixed every time u change the oil filter then you'll know

 

It you haven't replaced those heat-exchanger gaskets yet its cheap insurance to do it now and makes sense to do the oil feed line to turbo, both should be considered a 50,000 mile service interval. For $25 you can send an oil sample to Blackstone Labs and have it tested for contaminates and find out real fast what's in your oil.

 

Is there a diy for heat exchanger gaskets somewhere? I haven't done this

 

I'm sorry I think I forgot this was an N12 engine, not sure if you even have a heat exchanger like the one on my MCS N14 engine that has both coolant and oil passing through shared gaskets.

 

Yes but would this be a recommended preventative maintenance item for those of us with n14s? Or would it just be too big of a ball ache?

 

It it still going good?

 

1600kms post oil and filter change = still good.

 

That's great!

It's worth keeping the oil filter in mind. That's another reason to use a high quality filter - less chance of a bad one.

 

For the couple bucks extra you pay for an OE filter it is 100% worth it, near every 2nd gen car we get in with an aftermarket filter in it has started to fail and crush, even with 5k mile intervals.