D40 Engines & Gear change rpm.

Hi all,
I'm after some opinions from D40 Diesel owners
Ive heard people talking about there diesel engines loosening up over time and performing better and revving out smoother than when it was new,
What differences have you noticed over time with the behaviour of your engine,
Revs....Performance....ect

I'm about to hit the 10,000 km's and have not noticed any change as yet.

Id also be interested to know what rpm you change gears in your D40,
When not towing i generally change around 2500rpm,

Id be interested in any feedback.

I heard too that it would change at 10,000kms, Im over 30k now and havent noticed any difference in power economy or feel. I change anywhere between 2000 and 3500, usually around 3000 I guess.

There is no exact figure for an engine loosening up and it's not just diesels that do it, some are extremely noticeable and some just happen gradually over time which makes them less noticeable. In general all parts will loosen up at some stage as to what effect they have there is no definite rule.

I haven't noticed any major differences in mine since new but then mine was getting what I consider to be decent economy, was quiet enough and rode well enough from the day I brought it. I have had previous cars loosen up and appear to change nearly over night but it hasn't happened to every car I've owned.

As for gear changes mines an auto (so probably no use to your figures) and on the road I can usually get it to change before 2000rpm unless I stomp the loud peddle but since I'm never in a rush to get anywhere I don't do it often. According to scangauge I can drive for a full day on the road and not have the revs go higher than 2100 rpm. Towing is a bit different for me because on the road I really only tow a 4m tinnie or a 7 x 5 box trailer and neither stress the vehicle out much. On the farm towing the tandem and tri axle trailers around it's a bit different but then speed isn't an issue when they are on the back and 30kph on the road is about our regular speeds between farms.

I haven't noticed any change in mine either. 45k's.

I rev out first a fair bit because of the huge gap in ratio's, from there I try and keep the revs at 2000 rpm after each subsequent change.

Since the ratio's are spaced differently, there is no real "magic number" to change at. If the ratio's were linear, then you might be able to pick a change point and shift there at each change.

Depending on circumstances I find myself shifting at different revs to suit. For example, in most circumstances I use first gear to just get moving, then shift into second very early. Once into second, up to around 3K, then 3rd to 2.5K, 4th to same point, 5th to under 2.5K etc. That is assuming that I am accelerating up to cruising speed of over 80km/h.

But again, depending on circumstances...with a light load on board, there are times I skip gears....eg start in 2nd on downhill.....2nd, 4th, 6th.....or 1st, 2nd, 4th etc....modify revs accordingly.

Since the ratio's are spaced differently, there is no real "magic number" to change at. If the ratio's were linear (evenly spaced), then you might be able to pick a change point and shift there at each change.

Depending on circumstances I find myself shifting at different revs to suit. For example, in most circumstances I use first gear to just get moving, then shift into second very early. Once into second, up to around 3K, then 3rd to 2.5K, 4th to same point, 5th to under 2.5K etc. That is assuming that I am accelerating up to cruising speed of over 80km/h.

But again, depending on circumstances...with a light load on board, there are times I skip gears....eg start in 2nd on downhill.....2nd, 4th, 6th.....or 1st, 2nd, 4th etc....modify revs accordingly.

I have an auto R51 Pathfinder as well as my ZD30 Nav. There was no magic figure where it sudenly loosened up but I did notice around 15,000km that it was cruising up a particular daily hill in top gear with the torque converter locked up from bottom to top where earlier it used to unlock the converter every time.

Now at 150,000km without any noticeable loss of performance, oil use or excessive smoke.

Matt76 said:

I heard too that it would change at 10,000kms, Im over 30k now and havent noticed any difference in power economy or feel. I change anywhere between 2000 and 3500, usually around 3000 I guess.

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That's why i ask if it loosens up a bit over time,
I find my engine is screaming at around 3000rpm so I'm surprised to hear people changing at 3500 - 4000,
I understand it all depends on the driving conditions but being my first diesel maybe im just not used to the high revs, my mate always telling me that its fine to rev em out because diesels love it? and im a bit confused considering the red line starts at 5000rpm.

On another thing is it OK to use cruise control when towing?

I've only had mine for 3500k but try to change at a point that drops it back to 2000 revs as that is were it seems most comfortable kicking off from.
I've been wondering about the magical 10,000 loosening also.
I suspect it may be somethng to do with the ( also mythical ?) tweak to the ECU when you get your 10k service.
I recently had the earth strap off the battery - dicking about with the damn bluetooth dont ask - and I swear the engine has a new found sweetness - something to do maybe with ecu re-set ? I dunno. All a mystery to me.

Ankaz said:

On another thing is it OK to use cruise control when towing?

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There is probably many opinions on this and like the gear change issue there is probably no right answer for everyone.

As far as I'm concerned if you listen to what your vehicle is telling you while it's running you'll soon get an idea of just whether you can do such things. Towing in hilly conditions I wouldn't bother using cruise because I can drive a lot more economical than George can but on a fairly flat road where speed is fairly constant and it's constant for longer periods of time I wouldn't hesitate to use cruise when I was towing.

Jardsoooo said:

I've been wondering about the magical 10,000 loosening also

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HMMMM nothing magical here most diesel engines are only just starting to get run in at 100'000 and by that time the owner usually has had enough of the vehicle and trades it in

Mine has done 120k now and its starting to become free'r if you like and the economy is getting back to where it should be now that I clear the codes via the battery and not the peddle code clearing procedure

Cheers Marty

I noticed a change at about 1500kms that was when the egr blank went in.
Engine is alot better between idle and 1500 rpm. still only 4000 kms

Cheers Phil.

rebuilt engines

Ankaz said:

Hi all,
I'm after some opinions from D40 Diesel owners
Ive heard people talking about there diesel engines loosening up over time and performing better and revving out smoother than when it was new,
What differences have you noticed over time with the behaviour of your engine,
Revs....Performance....ect

I'm about to hit the 10,000 km's and have not noticed any change as yet.

Id also be interested to know what rpm you change gears in your D40,
When not towing i generally change around 2500rpm,

Id be interested in any feedback.

Click to expand...

My newest rpm is 2900. For me it is the fastest one I've got.

Im trying to find out how easy other navs are reving out as my is screaming at 3000 rpm in 3rd and makes a pretty wierd sound above say 2500 in 4,5 and 6th any info would be helpul. Thanx

You might be hearing the turbo spool up loudly by those revs could be what it is. Most the time you will be on boost but I find I can start to hear it between 2500-3500rpm spinning nicely.

good timing that i only just saw this thread, i don't drive ours very often, maybe a couple times a week.
car went in for it's 10k service on friday and i hadn't driven it for probably 1500km, drove into karratha today and mentioned to the missus that it seemed to pull a bit stronger than i remembered, she then said she'd thought the same over the last week or so but thought she was imagining it.
i think cause i don't drive it too often it's maybe a bit more noticeable than if you were driving it everyday as no doubt any changes would be very gradual.

I rarely go over 3k.

Tend to change around the 2.5k-3k rpm.
And I agree at 3k it sounds like its revving it's nuts off.

Cool, its not the turbo spooling i can hear that from about 2000 to 2500 rpm.