Thanks for your replies, interesting reading. Hard to be precise on speed/rpm/conditions - I'll try and note next time I'm out in the van. Also hard to record noises - I'll try but the engine and road noise may over power it. Maybe its me (I'm "mechanically sensitive") - wife has never mentioned it..... (Though she once drove 20 miles came home and told me there was a noise from the front CV joint when actually it was a flat read tyre, but hey, she remembered what a CV joint was
That was on a car, totally unrelated)
Hi BurntMarmite
That's quite a new van, is it not still under warranty ?
From your description, this noise appears when you are asking the engine to produce high torque i.e. wide "throttle" opening, and is present (at least it's more audible) at lower RPM. The maximum torque is usually controlled by the ECU and is fairly flat (constant) from typically 1500 to 2500 RPM, after which it drops. Engine torque is multiplied by the gearbox, progressively more as you go down from 6th through to 1st gear. So if the problem is on the output side of the gearbox (drive shafts, wheel bearings, engine mounts etc) it will tend to be worse in lower gears. However, as you still have the problem in 6th gear, this suggests to me that the problem is much more likely to be associated with the engine/flywheel/clutch or gearbox input shaft.
I'm a bit dubious about the turbo causing your described noise, as given the very high speed they spin at any noises will tend to be more of a high pitched whine.
Is the noise more noticeable before the engine warms up ? My 2008 engine gives a faint tappety rattle if I give it too much throttle (e.g after changing to 6th a bit too early) whilst still cold. I presume this is because of some mechanical clearances being a tiny bit wider under these conditions
Yes under warranty, and will mention it when it goes in for service.
Yes, 1500 upwards but its probably flat from 1500-2000, deffo increase (and note change) at 2000rpm
Noise is common if, say, going around a roundabout in 3rd then pulling away, or if doing 50mph in 5th (or 55 in 6th) and hitting an incline and putting more power in to maintain speed, it starts to make the noise if revs drop.
Noise is there when hot, so not related to being cold
Get it into a dealer ..!!
Thanks
Yes, under warrantee, and will be going to dealer shortly for its first service (early) but I don't have much faith in dealers and trying to understand what it is I'm trying to say. (I've had branded dealers where they are unwilling to allow technicians/mechanics speak to the customer, you have to speak to a non technical receptionist who passes messages back and forth, only for the the problem not to be looked at correctly as they didn't understand and having to book back in. - that was FORD)
Nissan van dealer, no complaints to be fair.
Fiat, unknown as yet (!)
Excessively low revs with throttle applied will cause vibrations. Any motor driven at low revs with throttle will vibrate, suggesting you might like to change to a lower gear. You didn't indicate how low the revs were.
Ian.
By low revs, I'm talking 1500 maybe. I know the vibrations you mean, its not that
