Assyst Plus

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Mactech

MB Enthusiast
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Porsche Macan S, BMW i3
Assyst Plus is a cunning little device which tells you when your next service is due. When my S class was new it told me there were 15K miles to an ‘A’ service.
Having done those miles now, I am still 6000 miles away from an ‘A’ service!
Whilst Mercedes say that the system takes into account ‘demands on the engine oil’ by such sensors as: Oil level and temp, Coolant temperature, Engine and road speed and engine load, I’m not sure that the algorithm is as complex as that.
Using just mileage, total fuel used (gives a good indication of how hard the engine is worked) and number of cold starts would give most if not all the information.
Does anybody know (or care!) what actual parameters are used?:confused:
 
This is briefly explained in the documents, didn't go and read it now but just wanted to add that it isn't just an algorithm, the car also has a sensor for oil quality (don't ask me how it works).
 
From one of the sensor manufacturer's web sites:

The sensor does not monitor a single parameter in the oil, such as water content. Additionally the sensor works on an index scale – it is not absolute. Contaminants such as Soot, Oxidation products, Water, Glycol, along with changes in TBN, alter the di-electric properties of an oil. The Oil condition sensor analyses a component part of the di-electric properties of the oil, known as the Tan-delta, which has been shown to change in proportion to the amount of contaminants, as above.

This measurement method is found to be sensitive to changes in contamination, but tolerant of variations in most widely available additive packages. It increases with the introduction of polar molecules such as Esters, Aldehydes and Ketones. Individual contaminants cannot be discretely identified.
 
Mine is crafty....It tells me I need a "A" service until a few 100 miles then it becomes a "B" one overnight.......think I will make sure oil is topped up lol
 
Assyst Plus is a cunning little device which tells you when your next service is due.

I would tend to call it mysterious rather than cunning.

And I think MB quite like to keep its workings obsfucated.
 
Assyst Plus is a cunning little device which tells you when your next service is due. When my S class was new it told me there were 15K miles to an ‘A’ service.
Having done those miles now, I am still 6000 miles away from an ‘A’ service!
What kind of use does the car get?

My C270CDi is pretty well only used for long motorway journeys and it would have gone over 20K mls for it'd first service, but I chickened out at 17K andbooked it in. Just before it went in, it flipped over to a B service. However the dealer happily carried out an A, but the car came back firmly calling for a B as its next service.
 
What kind of use does the car get?

My C270CDi is pretty well only used for long motorway journeys and it would have gone over 20K mls for it'd first service, but I chickened out at 17K andbooked it in. Just before it went in, it flipped over to a B service. However the dealer happily carried out an A, but the car came back firmly calling for a B as its next service.

My car gets used mostly for long journeys. During a week it will typically cover 600 miles with as little as 4 cold starts.
My wifes car (same V6 CDI) does about 200 miles a week with as many as 12 cold starts. That needed service at 15k and will need a 'D' service (so it says) at 30K. Because of her type of usage across the city, her fuel comsumption is 30 rather than 40mpg. Is Assyst cunning or cheeky...I'd love to know!:D
 
I'm not sure about the quality of this piece of advice that I was given by a Mercedes salesman.
I was told that I could extend the service interval by topping up with a litre of fresh oil when a service was nearly due and it would add another 1000 miles to the distance that the service was due.
I never put this to the test but would add up if oil quality was being measured, which I believe is the case.
I could never understand why my C class (180k) was due a service at 10K miles where most cars seem to be able to cope with around 12-15k.
My Audi is showing it's 1st service due at 19k!
 
I was told that I could extend the service interval by topping up with a litre of fresh oil when a service was nearly due and it would add another 1000 miles to the distance that the service was due.
Tis troo
 
I'm not sure about the quality of this piece of advice that I was given by a Mercedes salesman.
I was told that I could extend the service interval by topping up with a litre of fresh oil when a service was nearly due and it would add another 1000 miles to the distance that the service was due.
I never put this to the test but would add up if oil quality was being measured, which I believe is the case.
I could never understand why my C class (180k) was due a service at 10K miles where most cars seem to be able to cope with around 12-15k.
My Audi is showing it's 1st service due at 19k!

yes , ive seen the indicator go up after adding oil.
 
Sounds a good wheeze if you need to delay the service to fit with a schedule, but I'm not sure if you win much on overall costs.
If service cost are (and I'm taking a very rough average) £20 per 1000miles then adding £10 worth of oil to get another 1000 miles may seem atractive, but it has not offset any of the other wear factors on the car eg.brakes etc.
 
You can only add oil if there's space for it, of course! Otherwise you'll get the high oil level warning.

You could go the whole hog and suck the oil out and replace it - that should really stretch the interval out!!
 
You can only add oil if there's space for it, of course! Otherwise you'll get the high oil level warning.

You could go the whole hog and suck the oil out and replace it - that should really stretch the interval out!!


Hmmmm isnt that called a ...................service??:D
 
Hmmmm isnt that called a ...................service??:D

Don't be daft, it excludes all of the milk-more-money checks - ahem - I mean safety checks that are completed as part of a full service. :rolleyes:

:D
 
Yep, my Honda's due for a service- Actually overdue on time but well under on mileage. The standard main dealer price is £220 for a minor, and £300odd for a major. Wasn't terribly impressed with what this includes however- Oil change, a couple of filters, and loads of "Checks".

I think that, with 30k on the clock and a full main dealer history thus far I ought to bite the bullet, but still not happy! Wonder if they'd do an oil change and stamp the book?
 
My new W221 has the assyst in days not miles.
 
As ever the handbook is a mine of information:rolleyes:
'The service due date is displayed in days or kms depending on the distance travelled'
Since when? Too when? From what point? Frequent or infrequent use?

This system is so cunning we could pin a tail on it and call it a weasel!;):D
 

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