DMF/Inlet manifold link

[clightowler]

Hi all, just want to throw a coal on the proverbial fire and get everyone elses thoughts.

Recently replaced Inlet manifold after usual swirl valve failure, and have now got smooth acceleration right through the rev range and not the kick from the turbo at 2000 rpm as before (good 3mm vertical movement on old swirl flaps so must have been leaking boost massively).

The DMF has also started rattling for the last couple of thousand miles, and I was wondering if the kick from the turbo could have been increasing the strain on the DMF. I am aware that snatching the clutch etc has been suspected of causing prem failure and this is doing a similar thing really.

Wish I had had a bit more experience of this engine when I bought it as the kick has been there since buying it 2 1/2 yr ago, so it must have been knackered from the start!

Any how hwtas your thoughts, could the inlet manifold fault causing the turbo 'kick' be a key cause of the DMF failure?

[MickAP]

What mileage?

My thoughts are....The manifold and DMF all seem to go at the same time, or last the same amount of time. I think my swirl and DMF seem to be more noticeably deteriorating over the last 3k. Cars done 69k.

Mick

[GazVXLINE170]

The thing that really kills them is starting the engine without pressing the clutch and driving in too high a gear - labouring the engine. This puts additional strains on the DMF. The DMF actually does it's job under 1,000rpm when vibrations are more voilent. Yes it still has to deal with the torque spikes in the lower revs but there are alot who have had swirl valve issues but the DMF is fine. My DMF has been rattling, and lasted as such for ages which I put down to starting the engine with the clutch pressed and driving using the gears properly.

Btw, to the OP i'm not saying you drive your car badly. The theory you mention could prove the driving in too high a gear theory.

[clightowler]

Btw, to the OP i'm not saying you drive your car badly. The theory you mention could prove the driving in too high a gear theory.

No offence taken lol, I am actually a SAFED trained instructor for HGV, and practice what I preach when driving. have also always depressed clutch when starting as matter of course, I was taught to drive that way to begin with so its just habit now, unfortunatley, I dont know what damage had already been done as I bought the car second hand with 32K on the clock.

Car is now on 85k, but in all honesty the manifold would appear to have been shot when I got it as the car always had the kick at 2000rpm (which has now gone) and there has always been a slight rattle from gearbox area when starting cold, both of which reported at the time but Tech 2 said"no Fault Found" and with my only experience of common rail from 3 years earlier was hard to argue the case with Vx master Monke....Err Technician lol.

My reasoning comes from the clutch down on start argument, as the DMF will be subjected to the similar surge of Torque as on startup (although not as great). In reality, even if there is a link, its not as if anything can really be done about it as it would be hard to prove conclusively and Vx arent likely to do anything either lol.