Knocking

[c5greener]

Hi, my C5 X7 2.0 hdi  (2010)  has just started knocking when I raise the revs -  my wife was driving it today, and said it was really rattly, and then when she stopped to open a gate it cut out  and she struggled to restart it. About 5 minutes later she tried again and it started. AA  chap came out to it, started the car and revved it slightly. It sounds like a bottom end knock, he first of all thought there is probably a problem with the crank/bearings. After he towed me home, he must of been thinking on the way back and said it would be worth checking the timing belt, in case it has jumped a tooth. Could a timing issue like this cause  the engine to sound like a bottom end knock? 

[Johndouglas]

Yes it could.   First time I ever changed a Citroen timing belt I managed to get it set up one tooth out.   When I started it, although it ran ok, it sounded like a bag of nails.     How many miles has it done?

[c5greener]

Hi, the cars done 100k  cambelt changed at 70k 

[andymarve]

DMF perhaps? Mine knocked terribly when it went. Had the clutch replaced at the same time. The car, a 2008 C5 (X7) 2.0 HDI, had done about 150,000 at the time. The cambelt was done January this year at 160,000. 5000 miles on and the car's running lovely.

[c5greener]

Did you feel any vibration, or just the knocking sound?

[c5greener]

I have just noticed lots of air bubbles in the clear section of pipe going from the fuel filter housing - this doesn't seem normal to me, would this cause the loud engine knock I'm experiencing? 

[Johndouglas]

Does the knocking noise alter when the clutch pedal is depressed?

[c5greener]

Does the knocking noise alter when the clutch pedal is depressed?

No I wouldn't say there was much difference.  But on start up first thing this morning the engine was struggling to maintain steady revs and I could then feel vibration through the clutch pedal.  Still a bit concerned about all this air in the fuel!

[Johndouglas]

When was the fuel filter last changed?

[c5greener]

When was the fuel filter last changed?

6 months ago   5k miles.  There has been some developments since my last post. Took the car for a run again - the rattling got worse, and then there was some squealing; a bit like metal to metal which when a depressed the clutch - the squealing slowly reduced to nothing, managed to limp the car home - starting to think this is probably the Dual mass flywheel. what do you think. 

[Johndouglas]

I think you're right. It's your DMF or the clutch assembly that's at fault. Since the biggest expense is removing the gearbox first, it's as well to change the clutch assembly and the DMF. Time for a bank loan... :o

[andymarve]

I know it's a lot, but a local indy garage done mine plus clutch, crankshaft oil seal and n/s cv boot for £600. Citroen wanted over a grand just to do the dmf and clutch. So my advice if you're not doing it yourself would be to ring around.

[MikeLane]

Did you replace it with a new DMF or the Valeo conversion (solid flywheel + clutch plate with "long" springs)? Had mine replaced (car stopped on double yellows - very popular!) with the conversion and so far it's fine, just had to get used to slightly different feel.

 

Should have said that it knocked a lot for about 400 miles before failing completely!

Edited September 28, 2015 by MikeLane

[andymarve]

I replaced mine with the dmf.