Gear shifting with diesel

[en13]

Hi all,

I asked this in a different thread but no one seems to have answers so I'm back to you diesel experts

I have the habit of getting into neutral when I'm slowing down towards traffic lights- is this good/bad for a diesel engine? My mech says to just drive it like I do a petrol car- which is what I tend to do, go neutral whenever I can at short distances (I know it's unsafe in high speeds etc.). I've also heard it can wear out brake pads faster than normal. But I'm just asking in terms of the diesel engine- does this do anything bad to the engine?

I've also been trying to rev it a bit (as suggested by brackie in 'interesting articles > running in a diesel')- for example, using 4th gear to go at 100km/h, 3rd gear at 70km/h... is this too much strain on the engine? I've also done things like if I'm at say, 80km/h and 4th gear, I go to neutral for 4 seconds and then bring down to 3rd gear, rev it up again and repeat the process. I'm trying to vary the revs but I don't really know if this is the best way to do it?

is this okay and is it correct?

i'm what you would probably call a 'gentle' driver.. i don't particularly like to rev the engine but after all that i've read, babying it will have its consequences so i'd rather be 'cruel' to be kind.

any help is greatly appreciated; i still get a bit scared when i drive it- i feel like i'm going to choke it if i strain it too much but i just have to learn how to change my driving style.

thanks everyone!
and btw, i am TOTALLY enjoying my car- it's so fast!

[cetane]

Your post suggests that you car is new and is being run in.

If this is the case then it's important to vary the revs and work the engine hard on occasions in order to bed in the rings. Over-revving isn't good and nor is consistently under-revving. Sitting on a constant speed in the same gear is a sure recipe for glazing the cylinders and eventually causing low compression/oil burning problems down the track. Be gentle with the motor until the OIL is hot. Don't make the mistake of thinking that because the WATER temperature is in the mid-range the oil is hot. But don't "baby" the engine either because if you're too gentle then the rings won't seal. You won't "strain" the engine by occasionally and sensibly taking it up the gears at speed. The important thing is to work it and not to hold it at constant revs. Forget you have a cruise control until it's bedded in.

As far as putting her into "angel" as you pull up to lights etc... Don't do it. Pistons and big end bearings need to be bedded in evenly so even though you're bedding in on the thrust side, you need to use the engine as a brake in order to bed in on the non-thrust side. When I was a diesel fitter I could always tell the driving style of the driver of a truck by the way in which the engine components were worn when I stripped an engine down. A driver who used the engine as a brake would have even wear on the cylinders and big end shells. In those days (crash gearboxes and difficult down changes) lots of drivers pushed her into neutral and used the brakes to slow down. These engines always had more wear on the thrust side of the pistons and cylinders and on the top big end bearing shell. I bet their brake linings took a hammering.

Anyway... just my thoughts and I take no responsibility for any consequences that may occur should you decide to act upon them.

[STV4SYT]

Im assuming it is manual, dont want to be putting DSG into neutral when moving.

It is sllihtly different to driving a pertol car (assuming it is manual) as the usable rev range is a lot less than a petrol car, so u shift lower down than you are used to and more frequenly in the twisty stuff unfortunately (hence my DSG choice) but in comparison to a petrol u can normally take off with little or even no revs on the engine as opposed to having to match it in a petrol car. basically if u are doing it right the car will be smooth, if u are doing it wrong it will not be happy so u need to try a diferent approach.

btw, its a diesel, coasting to the lights isnt going to save that much fuel and i have to say, im a big fan of engine braking anyway.

[en13]

thanks for that cetane! and yes, it's a new car, just 2 days old!

so you're suggesting to always be in gear, even when slowing down- does it matter if i'm clutching down or not? i've this bad bad habit of clutching when i brake!

do you think i'm going alright with the gears in those speeds- 4th @ 100km/h and 3rd @ 70km? it doesn't even bring me up to 3500rmps... any thoughts on shifting to neutral for a bit before getting into gear (not braking). that really helps me vary the revs and i feel a bit like a mad woman if i speed up then slow down etc.. i'm also totally not used to the speed of the car!

yeah i read the running in thread, i only rev it if the oil temp is 90 (middle line). before that i go a bit slower and keep it less than 2500rmps.

of course, no responsibility attributed- just wanted some advice. i plan to keep her well and good!

[jets]

btw, its a diesel, coasting to the lights isnt going to save that much fuel and i have to say, im a big fan of engine braking anyway.

Actually coasting in neutral will use more fuel. When the engine is on the overun the fuel is shut off. When idling some fuel is used. This can be read on your display on the instrument.

[Mischa]

if you put it in neutral or have the clutch in, the engine will have to burn fuel to keep it ticking over.

if you have it in gear while coasting and use engine braking, the velocity of the car will keep the engine turning over while burning ZERO fuel.

whats the point in sticking it in neutral? just lazy? if so thats alright if you dont care about fuel consumption and premature brake wear. but it would be better all round for your car to keep it in gear all the way to stop.

simply revving the engine isnt going to seal your rings. you have to use hard acceleration to do so. so accelerate hard to the speed limit whenever you can but try not to go above 3800 revs in the first 1000kms.

oh and once your car is run in (around 1500kms) dont be afraid to stick it in 5th at around 60km and 6th at around 75. it barely burns any fuel using this method.

[Spoddy]

oh and once your car is run in (around 1500kms) don't be afraid to stick it in 5th at around 60km and 6th at around 75. it barely burns any fuel using this method.

1500? This is a diesel remember

Another question, at some point, because a diesel loves work and work under load, when should firm acceleration be turned into very firm acceleration under load like up a steep hill in a tall gear?

[Mischa]

1500? This is a diesel remember

well you know what i mean... run in enough to be able to drive it fairly normally. its not fully run in till 50000kms

[gregozedobe]

For slowing down I would be leaving the car in gear with the clutch out, changing down gears as I go. Aim for being in a gear that you could accelerate in if you had to (ie keeping the revs above 1400 or so after you have let the clutch out). Someday this habit may just save your life if you ever need to get out of someone's way.

If I am driving up a steep hill I would be keeping the revs above 2000. Just because a TDI will pull up a steep hill at 1400 or 1600 rpm doesn't mean it is good for the engine to do so.

If driving on the flat or downhill it is acceptable to run at low revs (unless you are still trying to run the engine in).

I am happy to use full throttle on a warm engine and regularly run it up to 3500 right from the very beginning (ie less than 100Km on the odometer), and up to 4000rpm once the car has done 1000Km.

I am firmly of the opinion that the best way to run an engine in is by allowing it to work, but there are many and varied opinions on the best way to run engines in (particularly diesels). Try a search on this and other VW forums and you'll see what I mean.

[Bazzamon]

I ran my 2 day old 1.9 dsg in by going on a 2000km driving 3 day holiday. By doing this you can often give the motor a variety of working conditions. I kept my revs below 2500rpm. I now nearly a year later I ahve the sweetest running little diesel motor. no oil consumed til 13000km & its down about 3 mm dipped when cold. Bazza