Discovery 300 Tdi sudden ticking/tapping noise

[Cave Johnson]

Hi all.
About three weeks ago after a drive to the supermarket which had gone fine my car started to make a horrible, loud ticking/tapping noise on the way home. Had been driven slowly to the supermarket, though with the engine warmer a bit more briskly on the way home but by no means over-revving it and certainly not thrashing it from cold.
The noise came on all of a sudden, no loss of power to be felt, just a loud noise which doesn't seem to get louder when the oil filler cap is removed. But the noise does rise and fall with the revs so I was thinking something to do with the cam possibly, or maybe a snapped valve spring?
Someone told me it could be a blocked injector but I can't see that making such a horrendous sound. Any ideas what it could be and the best ways of checking?
Not in too much of a rush so may do the work myself as I have a V8 to play with for now. Thanks.

 

[jamesmartin]

vacuum pump or valve cap

 

[Cave Johnson]

The vacuum pump for the brakes? How would one test to see if it is that, would it be a case of pumping the brakes and then keeping them held and start the vehicle or would that not be suitable to see if that's where the noise originates?
If it is a valve cap, is it a case of rocker cover off, replace and all good or would there be a likelyhood of engine damage?
Thanks.

 

[jamesmartin]

valve cap cover off and look at point between valve and rocker ,they have little cap between ,if broken or missing you can either fit another or remove all they are not necessary and before valve stem heads burr vehicle will be long scrapped ,set tappets after number nine method a nd 8 thou feeler guage,with vac pump undo 6 x 10 mm spanner size bolts .hold a piece of stiff card or similar over hole not rag as dont want risk of wrapping round cam ,run engine if vac noise gone err3539 new one no if needed

 

[Cave Johnson]

Hi, thanks for the advice will check it over.

 

[Cave Johnson]

Hi all, this is the developments so far:

1) Having figured that for the cost of a replacement, a vacuum pump would be a cheap fix, decided to run the vehicle to the auto parts store to buy a new unit. Started the vehicle, the ticking/tapping was there, set off, not sure if it's a case of my memory being bad due to spending more time driving the V8 recently, but could have sworn the Tdi was more vibey on tickover and the clutch bite point had moved (too close to top of the pedal travel) but didn't appear to slip. As revs rose so did the noise so kept the revs as low as possible while driving to the auto parts store. After maybe half a mile noticed the noise start to quieten, then disappear completely when the clutch pedal was fully pressed in (something that didn't make any difference before, but now it was quietening it down). Got to the store by which point the noise had completely disappeared. Very annoying. Local mechanic is next to the auto parts store so called in and had him take a look, he took it for a fairly long drive but we couldn't get the car to replicate the noise.

2) Based on what the mechanic told me, it most likely won't be the vacuum pump as if that was the case, the brake pedal would go hard or spongy and the brakes on my Tdi are consistantly sharp with alot of feedback (recently spent alot of money overhauling them with drilled/grooved discs, sintered pads, new hydraulic components, pipes, everything new apart from calipers which were given new seals and cleaned up.

3) On way back home noise came back, this time though the gearbox wouldn't change up, nor would it change down. I was stuck in 4th gear and had to pull over, with the engine at tickover the car could just about be shifted into 1st. Then it seemed to clear itself, slick operation again and the noise gone.

Now, the noise when under the bonnet did seem to be the back of the engine but lower than the rocker cover but couldn't for the life of me pinpoint it exactly where.
If it was the gearbox I could understand it quietening down with the clutch in as it would take load off of it, but why did it not make a difference when the noise first appeared when pressing the clutch didn't make any difference to the noise?
If it were clutch it'd make more sense, as I can't be sure but the car certainly feels less.. eager. Though I can't be sure it's not just disappointment after driving a 3.9 V8 for a few weeks and then going back to a diesel. Thing is though, the car has had in the last 12 months:

FULL brake system overhaul.
New heavy duty clutch kit (including release bearing, HD clutch fork, friction plate etc..)
Full stainless steel exhaust system.
EGR Removal

The car seems to be less reliable the more that is spent on it. Does anyone here have any idea what it could be from this new information?

Thanks

 

[jamesmartin]

did this noise start after h/d clutch fitted ,check gearbox oil,noisy vac pump doesnt make poor brake,spongy the guy dosent understand vac pumps hard if not pumping,was gearstickj stiff when not getting gears

 

[Cave Johnson]

The ticking/tapping noise only happened after fitment of the clutch, never did it before but it wasn't immediately after the clutch fitment, it's probably done about 600-700 miles since the clutch was fitted.
The car had a rattle before the clutch was fitted (I bought the HD clutch to stop it) as I thought it was the springs on the friction plate but I'm thinking that maybe the gearbox has a dodgy bearing somewhere.
Am I looking for just level in the gearbox or any metallic particulates in the oil (do they have a magnetic plug like MX bikes?)
Gearstick was not stiff when not getting gears. It moved from the neautral position across the 'gate' fine but would not slot into position for any gear up or down, as though there was nowhere for it to go, but when pulled over, it could be squeezed into first without too much fuss, then it was fine.

 

[jamesmartin]

ticky noise is h/d clutch may reduce given time change oil in gear box put in mtf ,brg noise in gearbox is whirring noise sump plug has magnet and will be covered in filings thats normal

 

[Cave Johnson]

Hi, thanks very much for the advice. I'll change the oil in the gearbox and think I'll also check the clutch system has been bled properly as pedal is lighter than my friends 300 Tdi clutch. Will keep updated on if noise goes, thanks.

 

[Amer]

ticky noise is h/d clutch may reduce given time change oil in gear box put in mtf ,brg noise in gearbox is whirring noise sump plug has magnet and will be covered in filings thats normal

Hey James,
I am having the same problem, even though I have a new vacuum pump,new vavle caps , recently done engine head and replace injectors with new ones. An still getting the taping nosie. I really don't know what else should I do!

 

[Dippypud]

Hey James,
I am having the same problem, even though I have a new vacuum pump,new vavle caps , recently done engine head and replace injectors with new ones. An still getting the taping nosie. I really don't know what else should I do!

Check lift pump function and manifold for leaks ...

 

[jamesmartin]

Hey James,
I am having the same problem, even though I have a new vacuum pump,new vavle caps , recently done engine head and replace injectors with new ones. An still getting the taping nosie. I really don't know what else should I do!

does it go if you raise the revs or press the clutch pedal

 

[Amer]

does it go if you raise the revs or press the clutch pedal

Yes if i raise the revs it becomes louder

 

[Dippypud]

Yes if i raise the revs it becomes louder

Dunt go then ...

 

[jamesmartin]

Yes if i raise the revs it becomes louder

yes ?you mean pressing clutch pedal has no effect and raising revs makes it louder, is this noise since doing the head

 

[Amer]

Check lift pump function and manifold for leaks ...

Left pump seems to be okay and nothing around the manifold. The only oily area i got is around the injector 3,2,1 and rear end of the engine ,

 

[Amer]

yes ?you mean pressing clutch pedal has no effect and raising revs makes it louder, is this noise since doing the head

Indeed clutch pedal has no effect. But raising revs males it louder. Yes since the time I have done engine head it keeps tapping infact it's been bothering me since i have start using this engine

 

[Dippypud]

Left pump seems to be okay and nothing around the manifold. The only oily area i got is around the injector 3,2,1 and rear end of the engine ,

Manifold should not leak liquid ... try listening with a stethoscope type device ...piece of hose etc ... take care of the moving engine parts though ...

 

[jamesmartin]

Indeed clutch pedal has no effect. But raising revs males it louder. Yes since the time I have done engine head it keeps tapping infact it's been bothering me since i have start using this engine

which head gasket did you use ,was head skimmed and piston height checked, are all the tappet adjuster nuts have the same amount of thread poking out above