Ray_QT

When I picked up an ordered Q5 TDI earlier this year, the salesman told me two things:

1) Always use the electronic brake when parking, even if you're on an even and perfectly flat surface because the transmission is very sensitive and could be damaged.

2) Always leave the A/C on at all times, regardless of the outside temperature because the A/C system does other things such as regulating humidity. Moreover, it won’t affect your gas mileage.

Question: Are those statements true? I have use the electronic brake religiously but I was wondering if there could be some additional wear using it all the time, even in my garage? As for the A/C, how come gas mileage is not affected slightly?

Don Keener

1) I never use the parking brake... Its flat as a board here in Florida. However... I think it activates automatically when you shut the car off... This is why you need VagCom to change the brakes... to release the brake. Im sure someone will confirm or dispute this.

2) The HVAC does dehumidify but dont run it if you are driving around with the windows open... It will try to cool the outside world and will be unsuccessful at doing so and burn fuel needlessly. I think your salesman exaggerates.

ex-quattro PETE

That's bull. There is even a display in the dashboard computer that shows you how much additional fuel (per hour) is being used by various accessories, including AC.

However, it is kind of true that at highway speeds, you're typically better off to just run AC than to drive with windows down.

kreativecid

I like when the car reminds you to roll the window up due to turbulence and better mpg with windows up and a/c on. My computer shows about 1/8 gallon use with a/c on; presumably windows down at speed uses more gas.

stash64

(1) could be true. If the car was hit when parked, I imagine the transmission would take more abuse if the brake was not on.


(2) is definitely not. If the A/C is running and removing humidity, the compressor is creating drag on the engine. I've been out of engineering school for a long while now, but I think the energy balance equation is still one of the key "laws" of physics.

timlocke

I always use the parking brake. After 40 years driving manual transmission cars it is a difficult habit to get out of AND use prevents it seizing up in our snowy, salty winters.

I leave the AC on all the time and the windows closed... I don't open the sunroof either. I find the buffeting at speed very annoying.

NorthValley

Ditto...except for 40 years driving and snowy winters!

motoguy128

It's mostly true and a good general statement. The parking brake is a bit extreme, but safety wise, you shouldn't trust the parking lock on the tranny and engine compression to hold to the car in place. It's not a bad habit.

My Honda CRV made a horrible clunk when you shifted out of park when on even a mild grade.

motoguy128

Honestly, I'm not sure why the parking brake doesn't just engage with Park now that it's electronic.

rdA4WtQ5

With the old mechanical cable parking brakes, if it isn't used regularly, it will rarely work when needed. good to use them every time. Our sealed electric belt driven parking brakes are much less problematic with non-use.
Probably a good idea on hills and with slippery winter conditions.