NT Diesel Intermittent Noise When Cold

[Stacho]

CATS, may I ask which pulley you mention? Was it the tensioner pulley on the a/c belt? If so, was it easy to remove, I.e just the single centre bolt? No nuts to catch on the back? Bit of a ball ache to get the whole pulley mount bracket off as that appears integral with the ac compressor mount. So if I can just spin one bolt out and replace with a Dayco pulley or similar then I’ll give it a crack. By the way, I tightened the drive belts as I found them pretty loose and haven’t heard the knocking sound since, but yet to be conclusive on that as it’s intermittent and I haven’t driven enough since to judge it. Will post back if/when I remove that pulley and have any conclusive evidence of its failure and/or contribution to the noise.

[CATs 4x4]

Stacho

Sorry cant help unfortunately. I had the job done by my independent mechanic so not sure how much work it entails.

It is the top crankshaft pulley I am refering to by the way. Not the other pulleys on there. It should be reasonably easy to check once you have removed the air intake pipe I would think??

CATS

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[_jp_]

The noise I'm getting sounds like its coming more from the side near the AC compressor and its tension pulley, rather than the top crankshaft pulley that CATs mentioned.

So far I've only noticed the noise 3 times in about 3 weeks.

[Morville]

My thinking is that the belts have gone hard and need replacing. A test for belt noise is to spray a fine mist of water over the belts with the engine running and see if the noise goes. Watch your fingers though.
Peter

[Stacho]

Stacho

Sorry cant help unfortunately. I had the job done by my independent mechanic so not sure how much work it entails.

It is the top crankshaft pulley I am refering to by the way. Not the other pulleys on there. It should be reasonably easy to check once you have removed the air intake pipe I would think??

CATS

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Not sure what you mean by top crankshaft pulley? You mean the one above the crankshaft as in the water pump pulley?
I also checked my belts for cracking and they look in great condition. I still haven’t heard the knocking since tightening the belts too, but its prominent on really cold mornings and it hasn’t been that cold since. So far so good though.

[CATs 4x4]

Sorry. I meant the MAIN crankshaft pulley. So no not the waterpump but the normal standard crankshaft pulley.
We are thus talking about the same one.

CATS


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[Stacho]

Oh ok. Thanks CATS, that clears it up.

[Vicbitter]

Yeah I've copped this noise a few times, only when really cold I've noticed. Once warmed up, all gone.
I imagine that since new to now (65000km so far) the engine has had little sounds like this pop up here and there.
Like recently I changed my oil using a 5w30 synthetic oil, and being still cold here, valves are seemingly louder.
Going to change to a thicker oil this weekend.

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[Stacho]

Hey mate. I ended up replacing the tensioner pulley and tightening the belts and the knocking went away. I still have a slight squeaking sound but right now haven’t been concerned. So tighten belts and replace that little pulley ($20) and you’ll be sweet.

[csimic]

Idler puley

Hi I had a similar thing and it ended up being and idler pulley on the air conditioner or serpentine belt one or the other I replaced all the belts and pulleys and no more noise. Just a thought.

[Mike DiD]

When I had a Petrol Pajero, it started making a banging noise when under load when totally cold, during its first winter.

The MMA Regional Service Manager agreed it did sound like a big-end bearing failing.

We were both relieved when they tracked it down to the Airconditioner Compressor hoses slapping together - once they had warmed up, they were softer and no more noise. They strapped the two hoses together and that stopped the noise when cold also.

[Xrsteve]

I have the same thing intermittent. On the odd occasion it happens I touch the throttle a light Rev and when it goes back to idle it’s gone lol. Can’t be to much all recalls etc done.

Adds character

[Tronic72]

similar issue on mine - was belts.

How many km's ? Sorry if i missed that.

I took mine in at about 125,000 with similar issue and mechanic said might be belts. We changed all belts and its a lot quieter. Its odd because it sounded mechanical and internal and I didn't think belts would be the culprit and only replaced them because he said they were due and was a cheap option to test.

[Woodzy]

I've got a very similar rattle noise that I cannot figure out either, nor can my mechanic. It does sound similar but would love it if anyone had any suggestions? Is way more noticeable inside the cabin and seems to be most prevalent on the rear drivers side of the engine!

My mechanic has checked the timing chain and apparently it's in pretty good nick. Has suggested the injectors but I don't have issues with the cold start, rough idle or high fuel consumption..

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[Allan2]

Replace the fan/alternator belt just make sure they are a matched pair, while you are there might as well replace the airconditioner belt also check the tensioner bearing with the belt off. Tighten them until you can only twist then 1/4 of a turn with your fingers at their longest distance between pulleys. The manufacturer will tell you they won't stretch but they do be prepared to re tension them some time later.
Regards Allan.