Lost 10mpg after visit to dealers

[Paulatic]

I've owned my Rapid Spaceback 1.6 crd for just over a year now. Bought as an ex demo from a dealer at 12 mths old. Ave fuel consumption has always been very good and usually in the sixties for most journeys.

Only problem I've ever had was water in the doors which was sorted.

However a couple of weeks ago the drivers side window got stuck down. Under warranty it went back to dealer for repair. A new motor fitted.

While it was in I got a new set of tyres fitted. Original ones were at 20,000 and getting close and had Firestone TZ300 fitted. I knew immediately on journey home mpg had fallen. After two weeks of doing usual journeys I now know I'm consistently loosing 10mpg. I've never seen the fuel gauge fall so fast!

My question is can this be due entirely from the tyres or can something have changed in Ecu while changing window motor?

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[67igor1]

For every job what is done at dealer site you should recive a confirmation...

[Kenny R]

Firestone TZ 300's have an F rating for fuel economy, which is pretty poor. What tyres were fitted previously?

[chrisgreen]

Kenny is right, the TZ 300's have a really low fuel economy rating, but an F rating is not enough on its own to knock 10mpg off fuel economy. I'm wondering if its a combination of new tyres and maybe not being inflated or balanced properly.

[eyegr]

Did they provide a reason for the motor failure? Did it have anything to do with the water in the door thing?

 

As for the tyres, as suggested, make sure to check the pressure. If it is low it will have large rolling friction hence the lower mileage.

[Paulatic]

Previously had a Dunlop, from new, fitted. I keep meaning to check what pressure they've left them I shouldn't assume they know what they are doing. It is something like a 15% decrease which I find hard to be due entirely to tyres.

Initially I had to go through Skoda Assist, the AA man who attended said the electrics are sealed in the door protected by polythene. So water shouldn't get to the motors. Google showed window failure, drivers side, to be a common fault with VW.

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Edited 8 December, 2015 by Paulatic

[eyegr]

Previously had a Dunlop, from new, fitted. I keep meaning to check what pressure they've left them I shouldn't assume they know what they are doing. It is something like a 15% decrease which I find hard to be due entirely to tyres.

Initially I had to go through Skoda Assist, the AA man who attended said the electrics are sealed in the door protected by polythene. So water shouldn't get to the motors. Google showed window failure, drivers side, to be a common fault with VW.

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How often do you use the driver's window? Sorry to bug you, I'm trying to figure out if it fails due to heavy use, no use or will fail regardless.

The motor costs over 100 pounds each, ouch.

[67igor1]

I've owned my Rapid Spaceback 1.6 crd for just over a year now.

...

I knew immediately on journey home mpg had fallen. After two weeks of doing usual journeys I now know I'm consistently loosing 10mpg. I've never seen the fuel gauge fall so fast!

New dealer tactics arrived... :peek:

 

"I was in my local Skoda dealership this morning, and was told by the service manager, that the softwear update would be carried out, automatically, whenever my car was in, unless I specifically requested it not to be done, every time the car was booked in.

He, not surprisingly, had no idea of what the update would be, nor any knock on effects to the BHP, MPG, EGR or DPF."

 

http://www.briskoda.net/forums/topic/379540-vw-emissions-scandal-thread-v2/?p=4462554

Edited 8 December, 2015 by 67igor1

[Paulatic]

How often do you use the driver's window? Sorry to bug you, I'm trying to figure out if it fails due to heavy use, no use or will fail regardless.

The motor costs over 100 pounds each, ouch.

I rarely open it but the OH does quite a lot to clean off the dew on a morning but she will do the lhs as often as the rhs. Apparently the relay mechanism is combined with the motor so whichever goes it's a complete unit. The drivers side door has never been bothered by retaining water. Just the back and passenger doors.

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[eyegr]

I rarely open it but the OH does quite a lot to clean off the dew on a morning but she will do the lhs as often as the rhs. Apparently the relay mechanism is combined with the motor so whichever goes it's a complete unit. The drivers side door has never been bothered by retaining water. Just the back and passenger doors.

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Thanks for the feedback. I also tend to keep it shut. If there is dew I spray water to clean it, I hate doing the up/down thing.

 

Now, if what 67igor1 said above is true, you should call the dealer and ask if they did any software update to your car's ECU.

Replacing the window motor has nothing to do with the ECU of course, except for the update now being a "default" action, as implied above.

 

I doubt that they did anything, just because I believe it is too early (by VW standards) to react on the emission scandals in Europe, but in any case you should ask (and please report back).

[67igor1]

... 10 mpg mean 16% down for your car economy and I don't belive that this is a result for tyres changed...

[RickTT]

Is it due to now your in the winter season, more stop start traffic, lights on, wipers, colder, heaters, short runs on cold engine etc etc... ?????

[brad1.8T]

Who buys tyres from a dealer?

 

I'd bet they've done a a software update.  We went from 8L/100km to 10L/100km in our Captiva with a transmission software update

[Paulatic]

Is it due to now your in the winter season, more stop start traffic, lights on, wipers, colder, heaters, short runs on cold engine etc etc... ?????

I live in SW Scotland, we don't have any stop start traffic. A trip to the nearest shop is nearly 20 Miles All my use is regular most often from cold, that is why I've monitored it for a couple of weeks and EVERY journey is down 10 mpg.

Edit: to correct spelling, bloody autocorrect.

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Edited 9 December, 2015 by Paulatic

[chrisgreen]

Cold weather will have an impact on mpg of course, but unless you are regularly running at freezing temperatures or in snow, the mpg drop off should not be that pronounced on a modern car.

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[Paulatic]

Who buys tyres from a dealer?

Not something I've ever done before. Reason I did was

the car needed a set anyway and the car was sitting there anyway while I already had a car supplied by them, at no cost to me.

I could have saved a couple of pounds a corner by taking the hire car back picking up my own and then driving off to a tyre services. Sitting in some gloomy reception area with sh**e coffee while it was done.

IMO the time was better spent at home for the money [emoji1]

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[chrisgreen]

One of the plus points of buying tyres at Costco (apart from good value tyres) - great food and drink on offer from the cafe while they do your wheels

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[Paulatic]

Invoice states "no campaign" issues.

Just spoke to dealer and they say again nothing was done other than window and tyres.

I've checked tyre pressures and they are correct so my advise to anyone is don't buy Firestone TZ300 tyres. They will work out very expensive.

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[Ootohere]

Have you checked and set your own tyre pressure. (& reset the TPMS.)

Have you checked the Tyre Size as now on, and are they a like for like replacement.

(obviously the new tyres will not be identical in rolling circumference to the ones they replaced, but usually that accounts for 1-3 mpg difference 

from brand / tread type etc.)

http://kouki.co.uk/utilities/visual-tyre-size-calculator

 

Then Zero the Miles etc, and do a Brim to Brim Fuel check and see just how much difference you really have on Average MPG..

[chrisgreen]

I'm also confused as to why a main dealer did no fit like-for-like tyres. They should have fitted Dunlops (still the factory spec for this car), or did you expressly ask for a cheaper or different tyre?

[Ootohere]

I did not mean like for like, brand etc.

I meant like for like size on the tyre walls.

 

Many considered by some 'cheap tyres' are a huge improvement over Skoda OME 'Cheap / crap' tyres.

[RickTT]

ps.. on my BMW E60, my MPG went down 6mpg over the winter while running winter rubber plus the cold element.

 

But thats also taking into account going from the weight of a 18 inch rim to a 16 inch rim too. (of course same rolling radius)

Edited 9 December, 2015 by RickTT

[chrisgreen]

I did not mean like for like, brand etc.

I meant like for like size on the tyre walls.

 

Many considered by some 'cheap tyres' are a huge improvement over Skoda OME 'Cheap / crap' tyres.

Yep - I know you meant actual tyre size (and you are right, it is important to check the dealer did not inadvertently fit a different profile). I'm focused on the brand choice though. The factory Dunlop tyres are fine, just bloody noisy, and should have been the default tyre offered by the main dealer unless the OP asked for something else. Curious if the OP did in fact request a different tyre or if the dealership stiffed him by selling him a questionable set of boots of its choosing (possibly because they were already in the workshop and it wanted rid of them).

[MickA]

Seems like a combo of temp drop and tyres to me. Looking at where the OP lives it would suggest that. I've had a couple of diesels in the not too distance past, a CDTi VX and another rather older VX with the 6 pot BMW TD lump in it. The MPG did drop off quite noticably in the winter months, especially on shorter runs as the engines takes an age to get to temp.

[eyegr]

Seems like a combo of temp drop and tyres to me. Looking at where the OP lives it would suggest that. I've had a couple of diesels in the not too distance past, a CDTi VX and another rather older VX with the 6 pot BMW TD lump in it. The MPG did drop off quite noticably in the winter months, especially on shorter runs as the engines takes an age to get to temp.

 

As the winter kicks in, I also noticed a ~0.5L/100km increase (sorry for the metric units :p ) in the consumption of my diesel. For someone who mainly does short trips it should be very noticeable.

 

Now, GoneOffskiroottoot's is an apposite remark as it never crossed my mind that there may be a difference in the tyre size. A larger diameter wheel would travel more distance per revolution, leading the car computer to think it travels less, hence lower mileage.