[Adrian4X4]

Hi KevXtrail

Car is same year as yours, 2008, and has 106,000 miles with 5W30 oil.
A lot of people on here have had much higher miles on the T31 X-Trail without such an issue, but age may be a factor with mine just as much as mileage.

The first thing I'm going to look at now is the accessory drive belt with its various pulleys and belt tensioner. My clattering / light clonking sound increases when I engage the air conditioning, suggesting that it is the air conditioning compressor itself (hopefully not), the belt tensioner (more likely), any one of the other pulleys, or a fault that has been described in another thread (linked a few comments up) where a rubber insert on the main crankshaft pulley starts to degrade and crack causing it to rattle.

The recommended process of elimination is to release the tensioner, remove the accessory belt, then run the engine for a short period to see if the noise disappears. Obviously not too long as alternator and water pump will not be connected. When belt is off I'll spin the tensioner, idler and other component pulleys in turn by hand to see if any of them has bearing wear noise, roughness or looseness.

I haven't yet had a day off work with dry outdoors weather (Northern Ireland) to explore problem further :sad:
Hopefully that will happen on Tuesday and/or Wednesday.

Adrian

 

[Adrian4X4]

On Monday evening after work I removed the accessory drive belt from the crankshaft pulley and ran the engine for a short while without it.
I believe the clattering noise goes away so at least it is not an internal problem such as timing chain guides etc.
Here is the result of my assessment of each pulley which doesn't make me all that much wiser:
- Tensioner has some noise when spun and a little lateral movement but not severe. Certainly the bearing is not on the verge of breakup or anything like that.
- Idler is silent without any looseness.
- Power steering pulley turns quietly and has no lateral movement.
- Alternator pulley spins freely with no lateral movement.
- Air conditioning pulley spins freely and quietly as far as I can ascertain, but has some lateral movement and noise if I try to shake it with force.
- Main crankshaft pulley obviously cannot be spun by hand. It does have a small lateral movement if force is used. However according to another thread it has a rubber insert (for damping purposes I take it) so some lateral movement I judge is to be expected. Rubber insert cannot be seen, pulley appears to be in at least two pieces with a metal outer disk/plate tightened over the actual grooved pulley wheel hiding it from view.

So at least there is nothing in dire need of urgent replacement, none of the bearings are on the verge of collapse.
So I may consider fitting a new tensioner to see what happens.
Drive belt itself is in good condition with no cracking or splitting.

 

[Ahto42]

The some noise is amplified while engine running. How old is the belt? any wearing marks?

 

[Adrian4X4]

Ahto42
I don't know how long the belt has been on the car. It was there when I bought the car in 2018 and car's previous service in the logbook suggests belt has been on the car for at least 39,000 miles / five years minimum, perhaps much longer. Belt has no cracking or obvious wear and when I compared it beside a new belt, it wasn't any longer, so it hadn't stretched.

Yesterday I fitted a new tensioner (from Schaeffler) and accessory drive belt (from Micro-V). Total price from my local motor factor was £70.72 and quality of tensioner and belt appear to be good.

The job was very easy indeed once the small plastic panel was removed (seven push in clips) and the front part of the wheel arch plastic interior guard was removed (five hex screws and a couple of push in clips). The tensioner has only two small bolts and neither were difficult to remove. Just take a couple of photos to remind you how belt is fitted as it does go around six different items! I will put a diagram below that I found online. Its not perfectly to scale but its ok. The tensioner and idler sit much closer to the crankshaft pulley in reality.

The unusual knocking noise now appears to have gone. Hopefully that's the end of that issue.

PS/I am however aware of a small click when I engage the air conditioning and a slight drop in engine revs which lasts a couple of seconds before stabilising. I did not notice any change before when air conditioning was turned on or off, but perhaps I just missed it.

 

[Adrian4X4]

Folks, I know this sequence of events is somewhat hard to explain but after a couple of weeks of normality, my chattering sound has returned, and is becoming quite loud again at times.

The fact that the new belt and tensioner I fitted suppressed the sound for a period of time, does suggest that the problem still lies within the accessory drive belt area. So it looks like I will have to strip off the plastic covers and take off drive belt for the third time to examine all pulleys again.

The sound does appear to come from one of the front mounted components, ie the alternator or air conditioning compressor, and not the crankshaft pulley which is described in other threads to be a known problem. Albeit, major lateral vibration / movement in the crank pulley could extend via belt to other pulleys.

Today, with the engine running I tried one of the Youtube suggested methods to help narrow down source of sound ie pressing a long metal item against each reachable component and pressing other end to my ear. I could only do this with the alternator (which sounded fine) and the air conditioning compressor. Quite worryingly the sound is accentuated when I listen to the air conditioning compressor using the above method, so that is a possible source.

However the air conditioning system is working great and has not given any trouble otherwise. When I examined all pulleys a few weeks ago with belt off, the air con pulley was quiet when rotated but it did have very slight side to side movement if I tried to shake it.

Does anyone know if the air conditioning pulley itself can be replaced, or do I have to replace the whole compressor when its working fine otherwise?

 

[Ahto42]

Pulley or bearing can be replaced. I sell many AC clutch bearings, even to main dealers.

 

[Adrian4X4]

I took the plastic cover off this evening again to check each of the accessories connected to the drive belt as I needed peace of mind that nothing critical is about to fail and leave me without the car to travel daily to work.

I removed the belt (very easy for me in that I have done it a few times now!) and checked each component again to see if anything has worsened.

Tensioner - new (see earlier post)
Idler - bearing is silent
Alternator - rotates freely and bearing is silent
Water pump - rotates freely with no internal noise and bearing is silent
Air conditioning - rotates with some resistance (probably normal), however bearing is silent and there is no noise from inside when rotated by hand. Pulley however has slight lateral movement if I try to shake it but nothing critical found.
Crankshaft pulley - also has slight lateral movement if I try to shake it. Again this may be normal (feel free to correct me) as pulley has a rubber insert which I take it acts as sound and vibration dampener.

So, nothing jumps out as needing immediate attention. I will continue to drive car to see if problem worsens and it becomes more obvious where the source of the rattle lies. When engine is running, it does appear to most likely come from the air conditioning compressor. However, the bearing as I have said above is quiet. So if the air con is the source of the noise, it could be something internal to the compressor. Not good news.

The only other possibility is that the fault stems from the crankshaft pulley rubber starting to separate (as described in another linked thread). Lateral vibration from the crank pulley could in turn be inducing a similar vibration in the air conditioning pulley through the belt. One cannot see if this is the case as rubber insert in the crank pulley is covered by an outer plate so would only be visible if pulley removed and that is too big a job for me right now.

I cannot throw any further money at the issue presently without further clues. Based on above, car appears safe to drive for now with critical components such as water pump and alternator all fine. I'll drive for a further period to see if problem worsens enough to help me narrow down.

I actually put the old drive belt back on this evening. If things worsen, its better to damage the old belt and keep my new belt on the shelf for later.

The saga continues...

 

[Adrian4X4]

Update....

A few hundred miles of daily commute later, and, yes, the noise has gone away again!

Stange, but true.

My engine and all components now sound totally normal.

I had pretty well narrowed down the rattle to my air conditioning compressor, something inside it, not the pulley or the clutch. So it must just have been a bit dry with little use during lockdown.

It now sounds fine again.

 

[Ahto42]

Mine started doing same noise. And now yt has more info.

The problem is alternator overun pulley. Sometimes they get stuck, mine was not, but still made the noise.


Searched the part nr and the Russian forum had same solution for that noise.
Nissan part nr 23151-JG71B/ INA OEM F-552305
INA 535015310 aftermarket
You need a special tool to remove it. Maybe it can be done without taking the alternator out. But it comes out very quickly if you have the tools.

Start from removing the right fron wheel, remove the inner liner, now you have access to the belt and tensioner.
With long T50 with a 10mm hex and a very long 10mm closed end spanner(like it is ment to do) or 15mm very long spanner to loosen the belt , 3mm hex to lock the tensioner.
Take a photo from the belt before you take it of, then it is easier to put it back. Or print it from the service manual.
Search M9R belt on YT.



In the engine room, remove the inlet hose, but it a side, and the plastic pipe.
Remove the bracket that holds the coolant hose and the plastic inlet pipe- 2x13mm bolts.

Now disconnect the alternator. If you want, then for the safe side, remove the neg battery cable. I was very careful and put a working glove over the big positive cable, as on bottom right on the photo.
Remember, it is always HOT.

The alternator it self has 2 13mm long bolts. Got them both loose from the top, the bottom bolt is better accesible from the wheel arch. Top bolt come out but for bottom, frame is in the way. use a small pry bar to get the aleternator loose, turn it o you can remove the bottom bolt.
Now wigle the alternator out.

Unfortunally there is no way to lock the alternator shaft. Used an impact to loosen it. Or use helping hands to lock the cooling fans with a screwdriver.

Left was from the factory, Made in China
Right is the aftermarket one.

Now but everything back in reverse order.

 

[Adrian4X4]

Ahto42

Many thanks for your excellent post above.
This will also be very useful to many others too.
I had been off the forum for a long time as my car had been off the road for timing chain repair - I'm sure you read about that in my other post.
Hopefully I will be back on the road soon.