What's the noise?

[10G]

What's the noise you hear from the motor when your just rolling along under light throttle, sounds like a loose chain. It normally goes away if you put a bit of load on the motor.

Something tells me it's pinging (or the diesel equiv) or a loose timing chain or similar.

[Bidja]

Cosh where do you start. Check oil level/pressure. Heat shield over turbo not loose?
Could possible be injector pump. Think you changed out belt tensioner a while back.
Just guessing, it is not a metallic ringing noise is it? Any difference hot/cold?

[mudnut]

Does it do it when the vehicle is stationary?

[10G]

Did it this morning (does it everyday), just out of the shed, cruising down a very very slight, almost flat street, 40kmh, in 3rd, very lightly touching the go peddle. If I push harder on the go peddle, it gets louder for about 1/2 a second then it goes. It's that very common noise you hear from diesels, sounds like a loose chain in the motor or something.

I only ask as it got worse all of a sudden after I added some oil to the motor.

[Plasnart]

G'day 10G, do you have the 4.2 diesel? If so it's common to virtually all of them.

Have a read here:

http://www.nissanpatrol.com.au/forums/showthread.php?18896-Rattle-or-Vibration-4-2-turbo&highlight=rollover

[10G]

G'day 10G, do you have the 4.2 diesel? If so it's common to virtually all of them.

Have a read here:

http://www.nissanpatrol.com.au/forums/showthread.php?18896-Rattle-or-Vibration-4-2-turbo&highlight=rollover

no mate, 3 litre. thanks for your help. Just read that thread and that noise sounds just like my noise. I hear it everywhere from diesels.

[10G]

So something's not quite right.

About 2 weeks back more than usual oil began coming through the catch can, I've been trialling letting it vent to atsmosphere post catch can, not been having problems, then noticed one morning I had a small pool of oil on the floor & the catch can barely had anything in it.

Next, this 'pinging' / gear lash noise increased, I am now hearing it when I didn't ever hear it before.

This week EGT's have gone up by 60 - 80 degrees.

I've noticed the exhaust seems to be noisier, more drone coming into the cabin.

Fuel usage has increased.

Boost always sat at 15, dropped when off the accelerator, but almost always sat at 15, now it's sitting at around 5-6, it does go up when you put your put your foot down but hardly gets above 12.

Coming home tonight, in 4th at about 70kmh up a very slight rise, put my foot to the floor. Boost at 4, speed increased marginally, boost stayed at 4 didn't budge.

I've also noticed that it'll pull ok in 3rd, but when I shift into 4th it just dies.

This is intermittant as well.

138,000ks, ZD30, dawse & needle valves, EGR block, catch can, 3" exhaust.

Would it be any use to remove power to the ecu to reset it?

I'm thinking a vacuum leak??????

[10G]

Took off for work this morning, EGT up to high 400s on a cool morning, boost getting up to 5. Turned around and put it in the shed.

[Touses]

Had similar happen over a new year trip.
Strange noise suddenly. Lack of power, low boost and noise increasing under load.
Turned out to be hose from turbo to manifold had slipped off the turbo. Clamp was never quite right and failed at that moment.
New clamp, all good.

Not saying for sure but could be a boost leak due to split hose or dodgy clamp.

[10G]

Yep, I'm going to over all the hoses on the weekend.

[Bidja]

As per edit note

For the noise, when it is happening at idle, open the needle valve gradually and does it stop?

[10G]

If CRD check that the VNT solenoid is still plugged in. CRD require it to be plugged in when Dawes/needle installed even though VNT solenoid is bypassed(vac).
Also check vac lines as you said and at idle have a look and see if the actuator rod is in the up most position (lever hitting stop). Check to see if the actuator rod lock nut has not come loose an allowed the actuator rod length to increase. If too long eng will become very laggy and exhaust will get more of a throaty sound and higher EGTs. The witness line up marks on the the adjuster thumb wheel to actuator rod will indicate any movement. Best leave it alone if looks like it has not moved.

For the noise, when it is happening at idle, open the needle valve gradually and does it stop?

Thanks Bidja, I'll check all that out over the weekend. Much appreciated.

[drgtr]

Is it manual? If its manual then thats the standard gearbox chatter. Sounds like rattle or pinging .

[vidya31]

Got the solution for the noise.

[10G]

Seems this is normal. It was enhanced by the vacuum leak that I had. Once I fixed the leak, the rattle almost went away.