Best practice in driving an Auto...

g60renshaw · Post by **g60renshaw** » Fri Feb 18, 2011 1:05 pm

Having always driven manual cars for the last 15 years and with all the gearbox horror stories of the X5, I was thinking as I drove to work today, what is best practice on driving autos?

On all my manual cars I have always been mechanically concious of not riding the clutch, taking the car out of gear and letting the clutch out where possible, not slipping the clutch etc..
While I was sitting at a junction today I put the car in Neutral as I figured surely this better for the gearbox than it loading up against the brakes in Drive....

So anyone got any thoughts?

Jay

X5Sport · Post by **X5Sport** » Fri Feb 18, 2011 1:20 pm

The only thing that I have always done, regardless of Auto or Manual is allowed the whole system to warm up properly before using larger amounts of acceleration, and also allowing the car to cool a bit when coming off a motorway for example so everything gets a chance to settle rather than just being switched off whilst still very hot.

Other than that I occasionally slip it into N when I'm going to be stationary - more to stop the driver behind geting glare from all the brake lights - than letting the strain of the transmission. Whether it makes a real difference I don't know, as it could just as easily be putting extra wear on the selectors that control the 'N' or 'D' systems. If it's a long hold then I'm more likely to switch the the engine off with the system in P.

Different people have differing views and opinions so it's an interesting question you pose, and the answers should hopefully prompt some debate here - what is the 'right' way to treat and auto?

gobiman · Post by **gobiman** » Fri Feb 18, 2011 2:15 pm

I am told that the warm-up point is crucial for longevity and that caning it before the engine oil (and other fluids) have warmed has a wholly disproportionate effect on wear.
The other bit of advice I had was never pull off the motorway with a red hot turbo and switch off immediately - allow a couple of minutes for oil circulation and cooling - for example in services. Probably sensible for any car but turbos are particularly vulnerable.
Don't know how accurate the advice is but sounds sensible.

g60renshaw · Post by **g60renshaw** » Fri Feb 18, 2011 2:19 pm

To be honest although valid and quite correct the warm up and cool down thing is something I have always done on all my cars anyway as its obviously as relevant to the engine as it is the gearbox. My query is more specifically about treatment of the autobox.

pvw10 · Post by **pvw10** » Fri Feb 18, 2011 4:25 pm

Warm ups are crucial for sure.
Unsure of the "right way" but i always select neutral if i am stationary for more than about 15 secs, the car feels uncomfortable to me sat on the gears/brakes. I mentioned this to an official tech once and he suggested it was better for the car this way with little wear on the selector as the movement "is far less than in a manual", this made sense to me, so i do it.

jap scrap · Post by **jap scrap** » Fri Feb 18, 2011 8:03 pm

Interesting topic looking forward to seeing a few replys on this because i am not long driving an auto as well always had manual cars.

IanP · Post by **IanP** » Fri Feb 18, 2011 9:09 pm

My last auto would not change up to top until the gearbox oil had got to 65C which was interesting when pulling onto a main road with a cold engine. This was to keep the load off the box, and was a design feature. If you keep the box in gear with the brakes on then it may overheat, for instance the old style stall test on auto boxes couldnt be carried out for too long because of this.
As mentioned earlier, I like to let the engine/box cool down if possible after a good motorway run because of the amount of residual heat in the systems, and if the engine is turbo'ed then it really needs to idle after a good thrash or the seals will get cooked or the oilways will get choked with carbon. Replacing blown turbos keeps my mate in business!!!!

Sundayjumper · Post by **Sundayjumper** » Sun Feb 20, 2011 10:14 am

I tend to put mine in neutral when stationary too, but seeing as it's done 108k miles and I've no idea how it was treated by the previous owners, anything I do now is not going to undo damage that's already been done.

ChewingBacca · Post by **ChewingBacca** » Sun Feb 20, 2011 10:35 am

The only thing under stress when holding on the brake is the fluid in the torque converter.

The likelihood of the torque converter overheating is negligible as its designed to cope with all loads and power conditions placed upon the drive train. Sat on the brake at 800 rpm is nothing compared to normal driving.

Lets face it, this car isn't the smoothest automatic to select gears, so leaving it in gear must be better than the sudden shock load against the brakes when selecting drive, but again the torque converter minimises the affect of this.

RE the turbo, ok give some consideration to heat but the worse thing you can ever do is blip the pedal then shut off. This spins up the turbo then cuts the oil pressure. Not good on bearings with parts running at tens of thousands rpm.

X5Sport · Post by **X5Sport** » Sun Feb 20, 2011 11:06 am

What was the thinking behind 'blipping' the throttle? I remember my Dad doing it, but I never have. Was it something needed for carburettor based cars to leave petrol vapour in the cylinders for easier starting? Fuel injection systems should not need that though - and a diesel engine would just burn it anyway as the fuel is cutoff at switch off but the engine will use it until it runs out.

ChewingBacca · Post by **ChewingBacca** » Sun Feb 20, 2011 11:44 am

Yes that's the back ground behind it. I come across people in all sorts of cars who just can't resist a bit of engine growl. Younger people with big bore pipes are typical.

lezmtaylor · Post by **lezmtaylor** » Sun Feb 20, 2011 12:26 pm

The idea of blipping the throttle, then switching off the engine,was to charge the cylinders with petrol fuel ready for the next start up.
Absolutely futile operation , as the fuel in the cylinders had evaporated due to hot engine !!!!!!!!!!!!!!
I am approaching the 3 score years and 10, and remember my Father telling me to do this, he could never understand the petrol evapouration thingy.
Also this habit washes the bores with petrol and effectively gets rid of the oil lubricating the cyl bores , resulting in excessive cylinder wear.
Lez

ChewingBacca · Post by **ChewingBacca** » Sun Feb 20, 2011 12:44 pm

I had an uncle who would also pull the choke out to further enrich the mixture.

X5Sport · Post by **X5Sport** » Sun Feb 20, 2011 4:13 pm

The fuel evaporation issue is just so obvious! As is the fact that flooding the bore with fuel removing the oil. Perhaps that's why older engines didn't last so well. Perhaps it's that I've never owned a car with a manual choke, they've all been autochoke. To start you pressed the throttle to the floor, let it off again and then started them. I guess some of us are just more mechanically aware than some, especialoy those who just see their cars as a tool. How times change......

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