Don't play around with a coolant leak...you'll find yourself doing a head gasket job or more. Plastic parts are known to fail.
For oil, I run 10w-30 or 10w-40 depending on the weather. Turbos run hot, and these provide more protection at that range. Have used them for years in my turbo VW cars.

 

The oil that comes out will be less than what goes in because of what remains in the oil filter and other areas. I get about 3.5 qts out when the dipstick shows full. I alway measure the amount of oil that goes in. The level will be just above the top bubble on the dipstick after running the engine.

As for letting the oil level go low - these engines are very sensitive to starvation. The vacuum pump needs oil pressure to function. If oil pressure is lost, these have been know to seize which causes a total loss of the engine as it is connected to one of the cam shafts and if that stops rotating then you have a valve meets piston problem. With low oil level, pressure can be lost by hard cornering. Because of that I alway top the level off once the oil level gets to the bottom of the top bubble on the dipstick.

That expansion tank is a PIA, a royal PIA... I disconnect the vent line the is attached at the top and plug the nipple on the top of tank with a piece of hose with a plug in it. Then I carefully lift it and move towards the passenger side of the car. The other thing I do is to put the shifter into reverse to get the transmission shift levers out of the way.

 

Okay, I'll definitely keep it topped up going forward. I measured in about 4.4 qts and the dip stick shows full even with a brand new filter. I'll check again after a few drives.

As for the expansion tank, there's the connection hose on the bottom of the tank and the connection hose coming to the top left of the tank. The top left hose is quite long so plenty of slack on that without disconnecting. The hose connecting to the bottom of the expansion tank is what's really short; no slack whatsoever. So moving the tank up and over to the left puts pressure on that bottom hose, causing the leak. I would have to empty the tank of coolant in order to disconnect it. The other thing is this same hose partially obstructs the oil filter cap as well, so that was also quite difficult to replace.

I don't quite follow your advice about putting the shifter in reverse... I'll have to take a look.

 

I just move the tank out of the way with a rag underneath it, no need to drain it to change the oil. I top it off at oil change or whenever I move it. Level stays the same till I mess with it.

 

That is what it should read...

Unfortunately, disconnecting the hose from the bottom of that tank will cause antifreeze to drain from the engine. This is the worst design... No choice but to push the tank aside. With the original tank in my car I have a few drop come out that connection. Not sure if the connection could have been a little tighter. Since I had that tank and hose replaced, I have not seen anything. I change my oil 3 - 4 times a year, before each of the track events I go to, so that tank got a lot of moving around. I had it replaced as a preventative measure; it wasn’t leaking.

If you have a manual transmission there are 2 levers that come out of the top of the transmission and these also interfere with getting to the oil filter and removing it. These 2 levers move when you move the shifter in the car. If you put the shifter into the reverse location, it will move the levers on the top of the transmission into a more favorable location for getting to the oil filter. I think “reverse” is the correct location. If not, try different gear locations to seen which locates those transmission levers favorably.

 

Or doggy pee pads. I use them anytime I am working with fluids to catch any drips or spills.

 

Why depending on the weather (assuming you mean ambient temperature)?

The cooling system of modern engines keep the operating temperature within the ranges specified by the manufacturer, irrespective of ambient temperature.

BMW states that any approved engine oil can be used all year long and any ambient temperatures. If no approved engine oils are available, up to 1 liter (about 1 qt) of any ACEA A3/B4 can be used to fill up, as long as its viscosity is either: 0w-40, 0w-30, 5w-40 or 5w-30. They explicitly warn against the use of any other viscosity grades.

Also: how can you be sure that using a 10w-X oil will not damage the engine or have long-term negative side-effects?

 

Or if you don’t want to mess with the coolant tank, take your intake hose off from turbo to air box, makes some room and you can get at it that way, extension and swivel socket, I use pee pads under the oil filter housing, my mechanic got oil all over tranny on our first oil change, 2nd one I knew what was going to happen and kept the mess to a few drops this time. Whoever came up with this design needs a good 5 fingers to the face 😉

 

There is a link above to a BIMMERWORLD article on engine oils for BMWs, which should apply to MINIs as well. It explains a lot about oil.

You are correct that the engine is designed to maintain its temperature above a certain point. Depending on the MINI (Gen 1 vs Gen 2 vs Gen 3) this can have a bit of a range, when looking at water temperature.

However, when the engine cold, it is the ambient temperature that determines the oil viscosity for that low temperature. That is whether you would use a “10w - X”, “5w - X” or “0w - X oil. The first number in that sequence is only the low temperature viscosity of the oil; it has no affect on the high temperature (operating temperature) viscosity. Also note that a lot of choice in the viscosity of the oil, these days, is a function of fuel economy requirements. A thinner oil flows more easily and there are lower pumping loses, which translates into better fuel economy.

BMW/MINI also designs these engines to operators at sub zero (F) temperatures where a 5w oil will act like a 10w oil at milder temperatures.

That said, a step up by one viscosity level will have no affect on the engine, especially in the lower temperature number where the engine does little of its operations. Add in the wear of an older engine (clearances open up) and milder climate (the original poster of that statement is from a southern US state), it may actually be good to step up to a 10w - X oil. Can I point to certified test to this point - No - But I am sure if you do a Goggle search you will find the same.


BMW/MINI does a lot to “protect” their warrantee and is fond of using any excuse they can to “void” it. If you have engine problems of any kind and they find out you used an “unapproved”, they can use that to void your warranty. That doesn’t mean if you do something other than what the book says that you will have damage in the long term.

Bottom line is, if you use a high quality oil of the grades they say, you will be fine. If you run a 10w - X oil, you might loose a little in the way of gas mileage, but nothing else.

 

I fear I didn't ask my question precisely enough. Apologies for that and please allow me a second try:

1. Since the operating (not startup!) temperature of the engine is kept within the same range, irrespective of ambient temperature, why do you use an Xw-30 oil for low ambient temperatures and an Xw-40 oil for warmer temperatures?
(As you have correctly explained, the first identifier is irrelevant for regular operating temperatures)

2. Engine wear during cold starts is not insignificant. So for an engine that is allowed to cool down completely between usage and especially for one being subjected to frequent cold starts compared to total running time at standard operating temperatures, getting the cold, thick, drained down oil as fast as possible to all friction areas is paramount. The "thinner" (i.e. lower "w" identifier) an oil is, the better in this respect. So,

a. if we assume that BMW requires 0w and 5w oils for a technical reason: how do you know that a 10w oil will not increase engine wear (or indeed incur damage in the long term) during the cold start phases and that it is able to provide the lubrication at cold temperatures engineers took for granted when designing the engine?

b. And even if a 10w (or higher still) oil will not (substantially/significantly) increase engine wear during cold start phases: Won't the lubricating abilities of a 0w or 5w oil during this time not be higher and faster applicable? What is the benefit of using a 10w-X instead of a 5w-X and especially 0w-X oil (provided using either of them is not restricted by the manufacturer)?

 

Car manufacturers will do a lot of research to see which oil will be the best for their engines for general use i.e day to day driving in normal conditions.

If you go to the extremes conditions i.e track days, worn out engine etc... then it might be worth considering other grade oil other than the OE spec.

 

Not to be a conspiracy theorist, but manufacturers only want the car to last through the warranty period. 5 years, 60k or whatever. They make their money on parts, labor, and new cars...

 

Then why do you adopt their way of argument in this case?

Yet there are things like extended warranty periods, government induced and mandatory recalls, brand value and reputation, growing (or withering) customer loyalty, compliance laws (especially the penalties they induce) and very powerful laws protecting moral principles in trade.

 

I’ll give you that these are interesting questions.

The N18 engine management system includes an oil temperature reading. When the engine is cold (sat overnight, say) I have found that when it is cold out (pick a temp: 10 deg F) it takes a lot longer for the oil to come up to temperature (~180 deg F) than when it is is warm out (say 60 deg F). So, a bit of a guess... It would be reasonable to assume that a Xw - 30 oil would do better (flow and lubricate) during that temperature transition time from cold to hot engine than would a Xw - 40 oil. As either is acceptable, then it won’t hurt.

A side point, I find that oil temperature, while driving normally, runs pretty steady. However, on the track the oil temp in my R56 runs about 30 deg F hotter than when driving normally. A Xw - 40 weight oil helps with that.

I think you are referring to the time between starting the engine and when there is oil pressure. This is a critical time. Yes, the faster oil pressure comes up the better it is on the engine. However, this isn’t like the old days before synthetic oil when it took, like, forever for oil pressure to come up on a cold engine. You wanted to be really careful to not rev or load the engine before then. With the modern synthetic oils, the oil pressure seems to come up almost instantaneously with starting the engine; when the light goes out, the engine has oil pressure. Also note that, when cold, a 10w synthetic oil is much thinner than a 10w conventional oil when you are looking at low ambient temperatures (say 10 or 20 deg F). So, I wonder how much of an issues that cold start wear is with these oils? This I don’t know.

I could only offer a guess to these and there are a lot of variables to consider. In particular you would have to know what cold start temperature the engine was designed for. If it was minus 40 deg F, that would be a lot different from it being a plus 40 deg F design. Yes, made up numbers, but if the engine was designed for -40 deg F, and it is only cold started at +40 deg and above, then a 10w at +40 deg F might be thinner than a 5w oil at -40 deg F. Without knowing that design temp and the typical start up temperature, it would be hard to say what the wear difference might be with different weight oils. As for the original comment about using a 10w - X oil, the person is in a warmer climate. So, maybe it has no effect on wear, if the design temp is much lower than that?

Not sure this helps much. This is just some comments to think about.

As was noted, the safest option is to do what the manufacture recommends for daily driving.

 

This is actually an argument for using lower "w" grade oils. An engine oil with a lower first identifier will have better lubrication characteristics during this transition period than an otherwise identical oil with a higher first identifier. The second identifier's "effect" on this is less.

Absolutely. I do not argue against the use of higher viscosity oils if required/beneficial and I certainly did not intend to question their advantages. Indeed, I prefer better long term wear characteristics than lower fuel consumption. I just think that if the 10w-40 oil is better for your engine and usecase than the 10w-30 oil, then it could and should be used all-year round (since their characteristics during cold starts will be pretty much the same).

Irrespective of the actual ambient temperatures, location of the user, usage and load of the engine, etc.:

Will a lower "w" grade oil not work better (i.e. faster and with more "cold temperature buffer") than a higher "w" grade oil at any given situation, both on startup and the transition phase? What are the advantages of using a 10w-X oil when being able to use a 0w-X oil (with the same second identifier and all other characteristics being equal)?

In short: By using a 10w-30 oil in winter you lose both the benefits of the -40 oil during operating temperatures while at the same time barely increasing cold startup performance. Wouldn't using a 0w-40 or 5w-40 (or even the 10w-40) make more sense?

A good, factual discussion always advances both sides, whatever the outcome! :-)
Peculiar example from the past

 

The only thing I will add is that bearings such as the ones in an engine rely on 3 things from the oil in order to work... Pressure, viscosity and flow rate. Each of these affects the other. If viscosity goes up, flow rate could go down. Pressure in the center of the bearing could remain the same, but because the flow rate is lower, the pressure at the edge of the bearing could be low resulting in the integrated pressure force being too low to support the load. Conversely if viscosity is lower, then flow rate could go up, but pressure drops and, again the integrated force is too low to support the load. I guess my point is there are no simple answers to your questions.

On the side - doing the track stuff I do I have had the chance to meet some very interesting people, including one of the principle people with Red Line oil. I had a very interesting half hour discussion with him. Different subject (very high oil temps, which at the time I didn’t know what caused them), but interesting no the less. The bits and piece of information like this I pick up give me a greater and greater appreciation for how complex all of this is.

Cheers.

 

With the manual transmission, this is what it looks like to change the oil with the transmission in neutral:


R56 transmission in neutral

If you put the transmission into reverse, you will see that you have a bit more room to work. Of course the coolant overflow tank has not been moved in these pictures.



R56 transmission in reverse.

You can see that the transmission lever has rotated to the right a bit (this is looking down while standing in front of the car). This change in location of that lever adds room to remove the oil filter and cap.