Reported economy in the toilet after air filter, oil and filter, and winter tyre change

[MrGreedy]

Recently done work as per the title (and mentioned in other threads on the forum).

New Hengst air filters (I didn't reset anything as I've read it will sort itself out).

Oil and filter change with Merc dealer oil and Bosch filter (also new orange turbo inlet seal).

Change from worn Conti Winter Contact tyres to Hankook icept Evo 3.

Not driven much since all the above, but this weekend I put some reasonable mileage on (several hours, average speed 50mph).

Whereas previously with the route and driving I took I would have expected a reported screen mpg of mid 60s, I got high 40s.

Today, super easy driving with high concentration hyper miling efforts on town outskirts/dual carriageway/ring road when I would have expected 50mpg I got 32mpg. Never, ever have I managed such shocking mpg on any drive anywhere.
Traffic was typical. No significant increase in stops starts or getting caught at every traffic light.

Could any of the items done to the car be the cause of a massive dip in economy?

 

[Skd884]

Tyres ?

Poor ratings and very noisey!



The newly fitted tyres on mine -

 

[W1ghty]

Very cold temperatures?
How is the thermostat?
Tyre pressures ?

 

[MrGreedy]

Very cold temperatures?
How is the thermostat?
Tyre pressures ?

Yes, it's cold, but I've driven round in these temps with no majors issues before on economy.

Thermostat was replaced Feb 2023. No issues that I can see with reported coolant temp. Gets up to near 90⁰C and stays rock solid.

Tyre pressures are 38psi all round, as they were before.

 

[BlackC55]

I would do an adaptation re-set on the engine first. Those tyres certainly wont help.

 

[MrGreedy]

Tyres ?

Poor ratings and very noisey!

View attachment 164836

Yes, they are not the best compared with summer or all season tyres, but they are full winter tyres for grip and this is compared with the winter tyres I've just replaced. I don't notice any noise difference except on concrete motorway, where if I listen carefully I can possibly detect a hum/buzz that maybe wasn't there before, but this is a 'can I hear something worse, I'm not sure?' level of noise, so not significant.

In 245/45/R17 the tyres are reported as:

Hankook iCept Evo 3
C for fuel
B for wet grip
72 dB for noise

Conti Winter Contact TS830 (so worse than what I've replaced them with)
D for fuel
C for wet grip
72dB for noise

By way of comparison, the Michelin Cross Climate 2 (one of best rated all season tyres) is very close to the Hankook at
C for fuel
B for wet grip
71dB for noise

So whilst I expect a very small difference between these and my summer tyres, I didn't expect a hugh drop of going from Conti winters to Hankook winters.
Could this realistically be a symptom of going from shallow (worn tread blocks) to full depth rubber?

 

[BlackC55]

Yes, they are not the best compared with summer or all season tyres, but they are full winter tyres for grip and this is compared with the winter tyres I've just replaced. I don't notice any noise difference except on concrete motorway, where if I listen carefully I can possibly detect a hum/buzz that maybe wasn't there before, but this is a 'can I hear something worse, I'm not sure?' level of noise, so not significant.

In 245/45/R17 the tyres are reported as:

Hankook iCept Evo 3
C for fuel
B for wet grip
72 dB for noise

Conti Winter Contact TS830 (so worse than what I've replaced them with)
D for fuel
C for wet grip
72dB for noise

By way of comparison, the Michelin Cross Climate 2 (one of best rated all season tyres) is very close to the Hankook at
C for fuel
B for wet grip
71dB for noise

So whilst I expect a very small difference between these and my summer tyres, I didn't expect a hugh drop of going from Conti winters to Hankook winters.
Could this realistically be a symptom of going from shallow (worn tread blocks) to full depth rubber?

It probably one of the factors.

 

[MrGreedy]

I would do an adaptation re-set on the engine first. Those tyres certainly wont help.

Gah, looking into this I have iCarsoft CR Pro v2. This doesn't do air filter resets.

I also need to fit a new headlight level sensor to the LHS rear suspension arm. V2 does do headlight adjustment either (although it does read the level correctly from live data).

I can see an improved diagnostic tool being purchased to help me with simple service tasks.

 

[BlackC55]

Gah, looking into this I have iCarsoft CR Pro v2. This doesn't do air filter resets.

I also need to fit a new headlight level sensor to the LHS rear suspension arm. V2 does do headlight adjustment either (although it does read the level correctly from live data).

I can see an improved diagnostic tool being purchased to help me with simple service tasks.

A better tool is going to be expensive and without an online connection to MB it will have limited uses.

Its often better value and easier to get it done by someone with the right equipment and knowledge.

 

[m80]

I get that there is some comparison to previous years low temperatures,
But not long since it feels like we are switched to winter diesel.
Recently I'm seeing a drop of what I reckon to be close on 10% worse economy.
But journey styles and all that, we can only estimate.

 

[OneForTheRoad]

Gah, looking into this I have iCarsoft CR Pro v2. This doesn't do air filter resets.

I also need to fit a new headlight level sensor to the LHS rear suspension arm. V2 does do headlight adjustment either (although it does read the level correctly from live data).

I can see an improved diagnostic tool being purchased to help me with simple service tasks.

I had the mb3 . It did air filter reset . For what it's worth.

 

[MrGreedy]

I had the mb3 . It did air filter reset . For what it's worth.

Yes, it's currently £260 for the CR Pro V3.0 and only £169 for the MB 3.0. I can guess that a good chunk of the £169 could be funded from the cost of getting my Merc specialist to reset the air filter and the ride level sensor. Once I've waited a month to get booked in with them (they are very busy!).

Unfortunately I'm not passing PCS for at least a month, otherwise I'd try booking in there.

 

[markjay]

https://www.tires-easy.com/blog/winter-tires-vs-fuel-efficiency/

"The fuel consumption average values can increase by 5% to 15% when using winter tires"

 

[Skd884]

I can never understand humans who fit winter tyres in the uk unless they reside in snow all year -