White_Disco

Active Member

• Sep 17, 2015

• #1

Been trying to diagnose this knocking noise on my 300tdi for a few weeks now, it's got 222,000 miles on the clock. Or is it a normal sound that I'm over reacting too? Thanks.

 

jamesmartin

Well-Known Member

• Sep 17, 2015

• #2

its not normal have you checked push rods ,valve caps etc,sounds to be cam speed but could be vac pump

 

TD5James

Member

• Sep 17, 2015

• #3

Could be # 1 injector knock ( loosen injector fuel pipe at injector while engine is running to where it leaks and see if noise changes do each injector one at a time if the noise goes away it is that injector that is bad )
#2 rocker arm clearance, bad rocker arm and/or worn cam etc. ( remove valve cover and check procedure to long to write down here, check RAVE )
hope this helps
# 3 check vac pump

 

Last edited: Sep 17, 2015

White_Disco

Active Member

• Sep 17, 2015

• #4

Thanks guys, I'll check all of the above points.

 

Paul D

Old, nackered 'n broke, but the Landy is fine . :)

Events Planner

• Sep 17, 2015

• #5

Missing nut/stud in exhaust manifold .. mine was the nearest to the bulkhead .. Couldn't find it for ages 'cos it sounds so obviously like a knock, not a blowing exhaust ..

 

White_Disco

Active Member

• Sep 17, 2015

• #6

I'll double check the studs, I've changed the manifold gasket so hopefully all still in place.

 

cosmicjohn

Member

• Sep 19, 2015

• #7

vac pump just done mine little push rod in it gets worn and taps like a bucket of bolts put a long bar screw driver on the vac pump put ear to the end and give it a rev and you will hear it

 

steveo

Well-Known Member

• Sep 19, 2015

• #8

I have the same knock, nothing has fallen off yet though

seems to be from the turbo side of the block, goes away as soon as its revved.

I will also follow the tips above

 

T

theflyingvegetable

Member

• Sep 19, 2015

• #9

Paul D said:

Missing nut/stud in exhaust manifold .. mine was the nearest to the bulkhead .. Couldn't find it for ages 'cos it sounds so obviously like a knock, not a blowing exhaust ..

Click to expand...

Mine too.

 

White_Disco

Active Member

• Sep 19, 2015

• #10

Looks like it's the vac pump, it's the only thing making a noise when I listen using a length of fish tank tube. Nothing from the rocker cover or injectors.no loss of power. I have changed the manifold gasket and decat down pipe during the course of the investigation. I'm very glad it's not the engine itself but annoyed that the £100+ wabco pump i fitted 5 years ago has started to play up. I'm tempted to fit a pattern part this time. Or I read something about fitting an alternator from a lorry with the a combined vacuum pump on it's then belt driven and blanking off the cam driven vac pump. Don't know how realistic this is, has anyone done it? Thanks for all the suggestions too btw. Amazing what a short video can do to diagnose strange noises!

 

D

discosrme

Member

• Sep 19, 2015

• #11

I have read somewhere people have fitted Vw/Audi electric vac pumps.

 

White_Disco

Active Member

• Sep 29, 2015

• #12

Saga update: I've changed the Vac pump, but it has not fixed the knocking noise, could've sworn that was where the noise was coming from. Oh well I have a spare now!! I have just bought some timing pins so I thought I would have a go at checking the timing. Lo and behold, I can't put the flywheel locking pin in when the Injection pump is locked. Could this explain the knocking sound? There's no excess smoke. This all started when towing a trailer to Cornwall, going up a motorway hill there was a lurch, the oil light came on but for a minute but then went off and we carried on and eventually noticed this new noise which seems louder at idle. I took some pics: in the flywheel hole, you can see an oily smudge where the locking pin misses the groove by about 4mm