Engine Knocking/tapping

[mothertruka]

Hi guys,

I have a 2007 manual Navara STX diesel turbo. Car has developed a loud knocking sound when car is cold. As soon as it warms up the sound dies away.
It sounds like its coming from the bottom of the engine close to the gearbox.
I cant tell whether it is coming from inside the engine itself or an external source.

The car drives fine and as I said as soon as it warms up it sounds like any other diesel but when cold, it is quite a loud knocking sound. Another thing to note is that it idles a little rough when this sound comes on.

If you guys have any ideas on what it could be or can reccomend someone who specialises in diesel motors please hit me up. I just want to get it fixed.

Thanks,

Adam

 

[Navmania]

Try this test first. Get a garden hose and with the bonnet open from the top and with the engine running at idle, spray water on the pulleys and fan belts at a steady pressure. Just trigger the hose on and off and see if the sound comes back. If it does then change your fan belts and check and grease the pulleys. If it doesn't make the noise then it could be the timing chain on its way out. Do the hose test first and see if it looks like it could be the chain then we can start throwing around ideas.

Cheers.

 

[doc]

I had a overrunning alternator pulley fail. It made all kinds of racket. Worth checking.

 

[mothertruka]

I will try the hose test and see if the pulleys/ fan belts are faulty tonight. Does that explain why the noise goes away when the car warms up? I was leaning more to an engine issue but I hope its not too serious.

I will have a look at the alternator pulley also.

Also if I cant locate the problem myself, Can anyone please reccomend a good diesel mechanic I can take it to. I am located in Melbourne, Essendon to be rpecise. Dont mind travelling for a good mechanic.

Thanks

Adam

 

[happy john]

They all are noisy under acceleration when cold it's more of a clatter but if you have had it a while and it's just started that's different try the hose test as said.

 

[Navmania]

It normally goes away once warm if it's the belts due to any moisture on them evaporating. Is it happening all the time or only on cold mornings or wet days. I found it did it on mine when I was doing a coolant change and it made the same sound as metal on metal like the timing chain rattling. If you get the noise with the hose it will only need fan belts changed and the pulleys inspected. Easy job to do yourself. We can guide you through it no worries.

 

[mothertruka]

Hey guys,

So I attempted the hose test. Not sure if I did it correctly but sound was still there with the water spraying or not. I have booked it in with Rankin Diesel in Bayswater. Has anyone ever used them before?

I have also realise that there is a pully screeching noise so not sure if it is related with the knocking or its just a pulley I need replaced.

Hopefully I can get a clear diagnosis of what is wrong once seen by Rankin Diesel.

Adam

 

[ericcs]

could very well be the alternator pulley as stated by DOC, had the same problem myself. couldn't find the run on noise, so took it to a dealer and when he started it the pulley fell off at his feet, so was an easy find in the end. had it fallen off while driving, it would have made a mess!

 

[doc]

<snip>. had it fallen off while driving, it would have made a mess!

Nah, mine fell off while driving. No harm done except to my pride.

That being said, the pulley was ****ed before it fell off...

 

[ericcs]

i had just finished a (100km/hr)2hr drive out heading west when mine let go. i suppose it could have been worse if the fan belt had flung it around the engine bay while cruising.
it must have been barely grabbing the alternator shaft as the alt. warning light never came on.
nissan showed a bit of good will, in supplying the parts free, as it was out of warranty, but only just1
eric

 

[vool104]

Has it got a heavy duty clutch up grade?

 

[mothertruka]

No heavy duty clutch upgrade. I have had the car for roughly 2 weeks.

The buyer supplied me with receipts and in 2012 the alternator pulley was replaced. Maybe they did a shit job, who knows. Hoping rankin diesel can tell me. I hear they are really good but really expensive.

Fingers crossed for me lads, I think I'm going to need the lube

 

[mothertruka]

Also have receipts for clutch and flywheel replaced in 2011. Price is $2200, is that normal, seems high.

 

[vool104]

That's a normal price for changing out the dual mass flywheel to a solid. Take into account if it has a heavy duty clutch they do rattle, the sound will be like a knock around the bell housing.