Different gear shift pattern in hot weather?

[Enobar]

A lot of you probably don’t have quite the same experience at high heat as I do but then Europe has had a few heatwaves too so maybe..

 

i started to notice last summer that I think the engine sounds slightly different in hot weather than cold - right from when I start the car.  I’ve also noticed recently though that the DSG seems to hang onto gears longer when it’s hot.  Today it was 47c where I live and I noticed the car hanging onto 3rd gear at 60kph, just shifting to 4h when I get to about 61 and ease off the throttle, and it sticks in 4th then when I drop back to 60.  When the weather is cooler, it would normally be a gear higher.

 

Anyone know of a logical reason for this behaviour or should I talk to the dealership?

 

 

[penguin17]

Viscosity/temp of gear box oil was my initial thought. Perhaps the DSG software/sensors monitor these things and adapt/perform accordingly, with component protection being priority (?)

 

OR yours is just broke! 

 

 

Edited 24 January, 2019 by penguin17

[JackySi]

My wild guess would be oil temperature.

 

P.S.: @penguin17 - That was just awesome timing!!!
 

Edited 24 January, 2019 by JackySi

[penguin17]

3 minutes ago, JackySi said:

My wild guess would be oil temperature.

 

P.S.: @penguin17 - That was just awesome timing!!!
 

My DSG oil must be warm 

[RickTT]

This is normal for DSG boxes in high heat ambient temp,  ie over 37'c ish (100'F)  if i remember correctly,  the gearbox holds onto the gears for longer due to the decreased efficiency of the turbo compared to if the ambient air temp is a cold 0'c.

 

Shifting at a very low rpm with very hot air intake could result in a stall, therefore the car protects this in the form of the DSG, Oil cooler plus various other facto algorithm's.   I know people have tried bigger intercoolers etc in the past, however its ECU related so needs to be coded out in the form of a map to over ride.

 

As air temperature increases, the density of the air, and the amount of oxygen it holds decreases. This means that the turbocharger has to work harder, spin faster and compress more air to produce the same amount of boost it would at lower temperatures.

 

 

[Enobar]

Thanks!  Great explanation