DSG affected by heatwave?

[manamp27]

The dsg in my vrs was acting oddly in today's 40 degree Sydney heat. I had it in 'normal' mode but it was holding gears as if it was in sport mode. Even when I tried to override it by using the paddles, once in auto it again held gears for far too long.

Anyone else experienced this?

[AdamD]

Yep, I've noticed that in my mum's Mk3 RS as well, in 40+ degree ambient. It was resolutely holding 5th until ~70km/h, although was happy to shift into 6th in manual mode with the paddles.

Curious behaviour, but I noticed it reverted to normal operation when the temperature dropped.

[h100vw]

I think heat can affect the DSG, hot/over hot oil becoming too thin. So the box stops shifting as well.

Had a mk6 GTI that played up in traffic until the DSG was serviced, may also be low oil level having some influence too.

[Spinifex]

Considering the engine oil temp stays around the 100-110 mark, I would assume the gearbox oil would also stay at a fairly constant temp, regardless of ambient conditions?

40 degrees is not such a hot ambient temp, considering these cars are exported all over the world, middle-east, india, etc, etc, where 40 degrees or more is considered average, not heat-wave.

If not, then VAG should invest in a gear-oil cooler on their vehicles.

[h100vw]

Considering the engine oil temp stays around the 100-110 mark, I would assume the gearbox oil would also stay at a fairly constant temp, regardless of ambient conditions?

40 degrees is not such a hot ambient temp, considering these cars are exported all over the world, middle-east, india, etc, etc, where 40 degrees or more is considered average, not heat-wave.

If not, then VAG should invest in a gear-oil cooler on their vehicles.

They do have a cooler but it doesn't mean that monster outside temps don't influence viscosity and hence operation of box.

https://www.google.com.au/search?q=dsg+oil+cooler&espv=2&biw=1280&bih=635&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiYyMKJlOvRAhUEo5QKHWquDg8Q_AUIBigB

Gavin

[Spinifex]

.....They do have a cooler but it doesn't mean that monster outside temps don't influence viscosity and hence operation of box....

Fully understood, but a difference of 5-10 degrees over "normal" ambient temps shouldn't affect an oil to that degree, considering the loads and usage involved.

I would understand this better, if we were talking 50 degrees difference in temp, but surely the transmission oil has a temp-range suitable for a greater variation than this?
ie: a car from Scandinavia and sub-zero temps being flogged in the Australian outback

If this was truly the case, any time someone has a fang through the mountains, or does a track day, would be increasing the internal oil-temp much more than an increase in ambient temp would affect it - considering the "remoteness" of the gearbox & cooler (ie, it's hidden underneath the car, surrounded by various bodywork and other insulating factors - not sitting on the roof in the absolute blazing sunlight absorbing ALL the ambient temperature)

I would suggest there's more to play at this than simple "hot weather" and I think the OP should get their car inspected.

Old/contaminated fluid is more likely the cause, than a few days of hotter weather.

[Spinifex]

I think heat can affect the DSG, hot/over hot oil becoming too thin. So the box stops shifting as well.

Had a mk6 GTI that played up in traffic until the DSG was serviced, may also be low oil level having some influence too.

I think this is more likely the cause, rather than the weather just being hot.

Or an issue with the oil-cooler..... normal auto-trannies are the same. Old fluid doesn't shift cleanly, and is more likely the cause, rather than just "hot" fluid.

The engineering of these things is such that the cooler should be easily able to handle the range of ambient temps for the geographic location of the vehicle..... ie: oil heaters for euro/scando cars, versus oil coolers for mexico, australia, etc, etc.

If the oil is getting too hot, the cooler is not doing it's job.

[h100vw]

I think this is more likely the cause, rather than the weather just being hot.

Or an issue with the oil-cooler..... normal auto-trannies are the same. Old fluid doesn't shift cleanly, and is more likely the cause, rather than just "hot" fluid.

The engineering of these things is such that the cooler should be easily able to handle the range of ambient temps for the geographic location of the vehicle..... ie: oil heaters for euro/scando cars, versus oil coolers for mexico, australia, etc, etc.

If the oil is getting too hot, the cooler is not doing it's job.

You'd be surprised how fast the oil heats up, ambient temp outside of 35 deg, could be much higher under the bonnet. Agreed the oil should tolerate this and for the most part does. There isnt a cold weather/hot weather oil.
Driving on an open road with 35degree temps is different to being stuck in traffic.

I have seen cars come off part way through happy laps with overheat codes and warning lights.

[manamp27]

Thanks for all the replies. The good news is that, with today's cooler weather, things were back to normal.

I rang the local Skoda/VW workshop and they advised that it's possible the prolonged stop/start driving in traffic caused the system to temporarily re-learn the shift points. Pfffft. I think it was the heat sending the system into a frenzy. Will keep an eye on it for now.

[VW Convert]

Thanks for all the replies. The good news is that, with today's cooler weather, things were back to normal.

I rang the local Skoda/VW workshop and they advised that it's possible the prolonged stop/start driving in traffic caused the system to temporarily re-learn the shift points. Pfffft. I think it was the heat sending the system into a frenzy. Will keep an eye on it for now.

I've been driving DSG equipped VWs (DQ250) for over 10 years, done over 200,000KM in that time and never experienced what you are describing. I don't buy the temperature affected theory.

Cheers

George

[AdamD]

I've driven literally dozens of DSGs, including several on the MQB platform, and many in high heat and on track. The only time I've experienced this behaviour is in the Skoda, in 40 degree ambient. The car was near-brand-new (oil did not require changing and the 'box did not require servicing), the gearbox was otherwise operating fine - shifts were smooth, clutch operation perfectly normal, etc etc. It had me moderately concerned at the time because the behaviour was new to me. As I said, manual shifting was perfectly normal - so clearly the gearbox was not preventing gearchanges, it was simply using a different shift programme for one reason or another. The shift patterns returned to normal on the next drive (next day) with ambients back in the 20s.

Minimising shifts to keep temps low seems like a legitimate explanation to me - although I've not experienced this in GTIs or Rs driven on track for extended periods. If anything, I'd put it down to the box going into a conservative shift mode to try and prevent a high oil temp condition.

[HPRS230]

Remember, you have lots of air flow on the track (100-200 km/h). Not so much when in traffic...

[adamtmitchell]

https://www.google.com.au/search?q=dsg+holding+gears+in+hot+weather

It seems to be pretty standard in recent generation VAG models with DSG gearboxes once you get up there temperature wise. I don't think it's anything to worry about unless you'll regularly be driving in 37+°C days.

[Martin]

One of the factors in deciding which gear to use is engine load
When the inlet air temperatures are high the ECU will be managing fuel mixture and advance differently - likely to have less power - that may force the use of a lower gear

[Davefonzi]

I'm glad I'm not the only one... I've experienced this happen on several occasions in my Skoda RS on high 30deg days. BTW, the car is only 6 months old.

Never noticed it on my TDI Golf 7 though...