V70: Engine Car doesn't decelerate

[Zedster]

I am new to autos and new to deisels, have driven manual perol cars for last 45 years. Earlier this year I bought a D3 V70 Auto 2011. I am not sure whether it is normal for deisel autos but when I take my foot off the accelerator from a fixed speed say, 60, 50, 40 etc. The car barely slows down and it is impossible to coast to an island for example the car is going way to fast even if coating from 50mph from 300-400m away, so I find myself always having to use the brake pedal. I find it quite alarming, is this normal?

If I contrast my petrol manuals if I take my foot off the accelerator at say 60mph I immediately notice the car is slowing down and I seldom need to use the brake pedal with careful driving. I find that impossible to achieve with my V70.

It may or may not be associated but when I first had the car I was averaging 46mpg, 3000 miles later I am struggling to get 40mpg no matter how carefully I try to drive it (I mostly drive on country roads). My 3.0L petrol Z4 consistently turns in over 40mpg.

Anyone any ideas?

[Simmy]

standard for auto box you will need to re learn how to drive with the auto box i hardly ever brake to slow down my trip computer shows 65 plus on a run 48 round town . iknow these are not true figures but its an indecation if you can replicate these figures most of the time

[Tatsfield]

If you car has Sports mode, try flicking the lever into Sports and seeing if the transmission ECU elects to drop a gear to slow the car. Some do and some, including mine, do not. If not, while in Sports mode, flick the selector into a lower gear manually and see if that drops a gear. You need to experiment with the box to work out the most effective ways of driving it to get it to do what you need. The AW box is robust but dim and I do miss the intelligent ZF box that I had on my previous car. Sadly Volvo do not use ZF for transmissions.

Diesel engines are not great at engine braking and coupled with the AW box it is an area where Volvos are not as good as some others.

[ferg55]

Lots of factors coming together in your V70 explain why this is quite normal:

• heavy car = momentum
• diesel engine = low rpm compared to petrol
• AW (aka Geartronic) auto box likes to remain in a high gear, especially if not in Sports mode (ref Tatsfield's comment)
• You're likely going faster in your V70 in the first place, because it's bigger and feels slower.

You get used to it, especially on motorways which become effortless

[apersson850]

Originally Posted by Tatsfield

Sadly Volvo do not use ZF for transmissions.

They did try, though. When Volvo first wanted an automatic gearbox, that could sit beside a transversal engine in a front wheel drive car (the 850), they asked ZF to build it. After a while, ZF replied that such a gearbox was impossible to design and build.
Volvo then asked Aisin-Warner, who built the AW 50-42LE.
After that, Volvo have continued with AW gearboxes for this configuration, in spite of ZF today also being able to make them. Perhaps they took the AW box apart to learn how to do it? I don't know.

Anyway, in drive mode, the AW TG-80 SC/SD trannys tend to sometimes disconnect the lockup when you let go of the accelerator, in which case you are more or less free-rolling during coasting. After a while, it may re-apply the lock, to make the engine go fast enough not to need any fuel at all to rotate (above 1500 r/min).
Selecting sports mode will normally shift down earlier and also apply the lock-up more aggressively, sacrificing comfort. Driven with reasonable care my XC70 D5 AWD automatic will indicate around 6 l/100 km average consumption.
If there's no traffic around to annoy, I typically let go of the accelerator some 700-500 meters before a roundabout, for example. With, say, 90 km/h at that time, I'm normally down to some 40-50 km/h at the roundabout, which may be appropriate to pass it, depending on the size of it.

[Ian21401]

My own car is a 1992, 940 petrol engine with the usual engine braking when the throttle is released.
I occasionally drive my daughter’s XC70 AWD D5 automatic which I believe has the AW gearbox. As the above poster has indicated, I usually “lift off” quite early, it not ridiculously early, to allow the car to slow down somewhat and then use the brakes to bring the car down to the desired speed. However, my daughter tends to use the brakes more than I do. At least it appears so when I’m the passenger. It’s a slightly different driving style compared to a manual.

[yostumpy]

Originally Posted by Ian21401

My own car is a 1992, 940 petrol engine with the usual engine braking when the throttle is released.
I occasionally drive my daughter’s XC70 AWD D5 automatic which I believe has the AW gearbox. As the above poster has indicated, I usually “lift off” quite early, it not ridiculously early, to allow the car to slow down somewhat and then use the brakes to bring the car down to the desired speed. However, my daughter tends to use the brakes more than I do. At least it appears so when I’m the passenger. It’s a slightly different driving style compared to a manual.

Ah! this driving style that your daughter has , could be the reason that these cars eat brake pads and discs, because folks drive them in the wrong way. Nowadays, when following other cars, I have noticed, whatever car/gearbox, that peeps don't engine brake anymore. pedal is either stop or go, nothing in between, and people hit the brake now when they think, about anything, as the lights seem to be on and off for no apparent reason, (men and women). Learn to read the road ahead, and you hardly need to touch the brakes at all, even in an XC70.

[Ian21401]

Originally Posted by yostumpy

Ah! this driving style that your daughter has , could be the reason that these cars eat brake pads and discs, because folks drive them in the wrong way. Nowadays, when following other cars, I have noticed, whatever car/gearbox, that peeps don't engine brake anymore. pedal is either stop or go, nothing in between, and people hit the brake now when they think, about anything, as the lights seem to be on and off for no apparent reason, (men and women). Learn to read the road ahead, and you hardly need to touch the brakes at all, even in an XC70.

I must defend my daughter’s driving style as she is a trained class 1 Advanced driver, (as am I ) so doesn’t fall into the category that you describe, she just doesn’t do it quite the way I would.
However I do agree with your general observation of the brake lights of preceding vehicles constantly being on and off. It also fits in with the fact that many drivers simply drive far too close to the vehicle in front.

[apersson850]

My brake pads typically last about 200000 km in my XC70 D5 AWD automatic.
I have replaced all four discs now, due to wear, but now my car is near 370000 km on the clock.

[Tatsfield]

I previously drove auto 2+2 coupes where the auto transmission allowed for engine braking in very much the same way as a manual box when used in a sport driving manner. My XC70 makes you work quite hard to use the engine for braking but the system is well adapted to acceleration. So driving my previous cars would entail dropping gears for bends or overtaking and changing up afterwards and not using the brakes very much at all, while the XC70 still demands that I use the brakes to decelerate the car if I drop into Sports mode or even if I use the gear selection override. It's a heavy car, diesel engines don't engine brake as well as petrol engines and the AW box, despite having a Sports mode, really has no sporting pretensions. I expect heavier brake wear with the XC70 than I had with my coupes.