No Oil Dip-stick with new car engine.. How does it know?

Started by Cunning Plan, January 07, 2015, 01:11:59 PM

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Cunning Plan

I was playing with a new Mini (not mine), F55 1.5d to be exact and there is no oil dip-stick, instead you have to use the on-board computer to run an oil check, which then displays the results on the centre console screen, similar to this one, but imagine an image of a dipstick with a level indicated on it:



That bit is quite simple, you would think a sensor just detects how much oil there is and displays it on the screen, however, to measure the oil, you have to have the car running and in neutral, which then prompts the system to start checking the oil.

On older engines, I have always waited for the car to cool and the oil to return to the sump to get an accurate measurement of exactly how much oil is in the sump and therefore, available to the engine. My understanding is, if the engine is running or has just been run, the oil will be distributed around the engine, in the journals, head, passageways, turbo etc, so the amount in the actual sump will appear to be lower.

So, how do new engines, without dip-sticks measure oil?  
1968 VW T2 Bay Bus (currently being restored and upgraded)
1999 Jeep Cherokee XJ (modern classic daily driver)

Big Mouse

I suspect its measuring pressure rather than amount. Fluctuation in the pressure would indicate a leak therefore it needs oil. That raises the question of how do you know when you've fed it the right amount of oil? the only way is to drain it, fit a new filter and top up with the recommend amount of oil.

Oil level problems with new (2007+) minis is well covered on the interweb

Roadkill

It might have a level sensor - like in a fuel tank ?

And, in fairness, oil level with the motor NOT running is kinda pointless . . . You could put 10 litres of oil in the engine but, if when running, it only is using 1 litre, then the other 9 litres is extra weight and drag on the motor (within reason).

Cunning Plan

Quoting: Big Mouse
I suspect its measuring pressure rather than amount. Fluctuation in the pressure would indicate a leak therefore it needs oil.


That makes sense.

So do you think it is drawing oil through a 'device' which expects X amount of oil to pass through in X time, if it is less by pressure, then you have less oil?

I will take a picture of the dash display when it has completed the check, it seems to know exactly the amount of oil in the system. It even shows a dip-stick with a level on it, so the oil can be somewhere between the minimum and maximum mark.

Quoting: Big Mouse
That raises the question of how do you know when you've fed it the right amount of oil? the only way is to drain it, fit a new filter and top up with the recommend amount of oil.


For oil changes, I guess it would be the same as any other car in that you would already know the amount of oil to put in by looking at technical specifications.

I *think* for top-ups, the computer display will tell you how much to put back in. Total guess at the moment though as the car is at maximum level.

Quoting: Roadkill
It might have a level sensor - like in a fuel tank ?


That would work if the engine is 'off', otherwise the oil would be fluctuating with every movement of the crank, right?

Quoting: Roadkill
And, in fairness, oil level with the motor NOT running is kinda pointless . . . You could put 10 litres of oil in the engine but, if when running, it only is using 1 litre, then the other 9 litres is extra weight and drag on the motor (within reason).


I understand what you are saying, that the engine will only use X amount at any given time. However, the oil is not just for lubrication, it is also for cooling, so my understanding is, if we pretend that the oil is a solid cube, once one cube has gone around the system, the next cube is cooler in the sump waiting to go around next.

With that in mind, the engine has been specified to need, for example, 6 litres of oil as the engineers have worked out that 2 litres are required to go around the engine at any one time, 1 litre is in the filter being cleaned and 3 litres are in the sump cooling and providing lubricant to the bottom of the crank.

1968 VW T2 Bay Bus (currently being restored and upgraded)
1999 Jeep Cherokee XJ (modern classic daily driver)

art b

This forum needs, ''YOU'' posting,Not just reading ! :moon:

Cunning Plan

Quoting: art b
I prefer to pull my dipstick out..


MKB urban legend 'Say Lubricant two times in one post and ArtB will appear'

1968 VW T2 Bay Bus (currently being restored and upgraded)
1999 Jeep Cherokee XJ (modern classic daily driver)

art b

This forum needs, ''YOU'' posting,Not just reading ! :moon:

art b

i cant believe how much the mini depreciates ..

it seems to be down to dodgy electrics and oil issues .
This forum needs, ''YOU'' posting,Not just reading ! :moon:

Cunning Plan

Quoting: art b
i cant believe how much the mini depreciates ..


Example? I found that they hold their value as much as a VW, in-fact, almost identical second-hand prices when comparing age and mileage and certainly no where near the amount dropped by Fords, Shitrons, Pugs etc.

Quoting: art b
it seems to be down to dodgy electrics and oil issues .


The new shape (F55/F56) are completely BMW Mini, the Diesels are made in Austria, no more Peugeot crap!
1968 VW T2 Bay Bus (currently being restored and upgraded)
1999 Jeep Cherokee XJ (modern classic daily driver)

Roadkill

Quoting: Cunning Plan
I understand what you are saying, that the engine will only use X amount at any given time. However, the oil is not just for lubrication, it is also for cooling, so my understanding is, if we pretend that the oil is a solid cube, once one cube has gone around the system, the next cube is cooler in the sump waiting to go around next.


True, but by introducing an oil cooler (for example) you could cool the oil more efficiently.

That's starting to get away from the original point, though . . .

Cunning Plan

Where is Incursus, he might know how it works?

Doesn't he work with new car electronics?
1968 VW T2 Bay Bus (currently being restored and upgraded)
1999 Jeep Cherokee XJ (modern classic daily driver)

Roadkill


Incursus

Quoting: Cunning Plan
Where is Incursus, he might know how it works?

Doesn't he work with new car electronics


Yeah.. Infotainment...

Quoting: Roadkill
. . . and his wife has a new Mini, too


Pretty sure it has a dip stick.. tis a couple of years old now though.  Renaults have had electric oil level sensors for years, my brothers mid 90's Laguna showed you the oil level on start up iirc

Roadkill

The Renault did it with the engine off, though, before you started the motor.


Cunning Plan

Quoting: Incursus
Pretty sure it has a dip stick..


I got a chance to have a proper look at the car today and it DOES still have a dip-stick in the engine bay! The car is packed full of electronics, so I guess it gives the owner a choice of how to check the engine, especially if you do not know anything about engines.  

\" target=\"_blank\" rel=\"nofollow\">http://www.sensorsmag.com/sensors/leak-level/a-dozen-ways-measure-fluid-level-and-how-they-work-1067


Interesting link, thanks.


Here it is working anyway:



1968 VW T2 Bay Bus (currently being restored and upgraded)
1999 Jeep Cherokee XJ (modern classic daily driver)