NT 2009 3.2 Noticable sound during load

[rwnaas]

Hello,

So I bought an NT 2009 3.2 147KW, very happy with the car but there is a rotating/humming sound coming at low idle during load (Car has 182K on it).

This is what I have done to see if it got better:
* I changed the aircon belt and the alternator belts, checked the pulleys.
* Changed to a high-quality oil and filter (Synt 5W-30)
* tried to turn off the aircon.
* Took a look through the oil cap to see the timing chain guide, which looks fine.

I also noticed after lifting up the vehicle with the engine running, that there was a ticking sound coming from between the engine and the automatic gearbox.

Chain tensioner was changed at Mitsubishi workshop in early 2018 (recall) with the previous owner when the car had about 160k on it.


If it was to be the valve lash, wouldn't it be noticeable during idle without load?
How much work to do adjust valves on this car, is it a guide out there?

Looking forward to your paj advises

[spot01]

A few thoughts:
- the tensioner recall was a few years before 2018 IIRC, so the previous owner took their time getting it done. (my guess is they ignored it until the car had to go in for the airbag recalls?). I wonder if any damage was done to the chain by leaving it for so long, although only a very small number of tensioners were actually faulty. You could ask the dealer whether the tensioner they removed passed or failed the test they do on it. If it failed, ask re what they did re checking the chain, etc.
- when was the auto fluid last changed? It was due at around 180k for normal use or at 90k & 180k if used for towing &/or severe conditions. Note quite a few people who have changed the fluid at these intervals have said it looked very bad & perhaps it should be done more often.
- the tappets take an experienced mechanic about 3 hours plus a kit of parts is required, so not a cheap job & probably not for DIY unless experienced - the high pressure fuel rails have to come off & are difficult to replace correctly. MMAL says every 30k, but some people suggest 60k. Note at the 6th removal the fuel rails need to be replaced at large $. If it has been done per the book, new rails are needed at 180k.


Of course the noise may be nothing to do with the above. These engines make a fair racket at the best of times, so difficult to diagnose without actually listening to it. Does the noise change if the engine is cold or hot?

[tiger99]

I have a low hum at idle and I know it’s the filter box fitted with an aftermarket air filter. I once changed to a genuine and the hum went away. Back to aftermarket now and the hum is back. You can test this by putting pressure with your hand on the air box whilst idling.

[rwnaas]

A few thoughts:
- the tensioner recall was a few years before 2018 IIRC, so the previous owner took their time getting it done. (my guess is they ignored it until the car had to go in for the airbag recalls?). I wonder if any damage was done to the chain by leaving it for so long, although only a very small number of tensioners were actually faulty. You could ask the dealer whether the tensioner they removed passed or failed the test they do on it. If it failed, ask re what they did re checking the chain, etc.
- when was the auto fluid last changed? It was due at around 180k for normal use or at 90k & 180k if used for towing &/or severe conditions. Note quite a few people who have changed the fluid at these intervals have said it looked very bad & perhaps it should be done more often.
- the tappets take an experienced mechanic about 3 hours plus a kit of parts is required, so not a cheap job & probably not for DIY unless experienced - the high pressure fuel rails have to come off & are difficult to replace correctly. MMAL says every 30k, but some people suggest 60k. Note at the 6th removal the fuel rails need to be replaced at large $. If it has been done per the book, new rails are needed at 180k.


Of course the noise may be nothing to do with the above. These engines make a fair racket at the best of times, so difficult to diagnose without actually listening to it. Does the noise change if the engine is cold or hot?

Thank you for your reply.

* You are right about that the tensioner was replaced together with the airbag recall, I tried to call the workshop regarding it but they did not have any data if it had passed the test.

* Auto fluid has been changed at 178k, that was a service from aftermarket workshop and they told me it was changed. If it really has been done am i unaware of, maybe I should change it myself.

* The noise is more noticeable when the engine is cold.

I will see if i can make a recording of the sound and post it here.

[rwnaas]

I have a low hum at idle and I know it’s the filter box fitted with an aftermarket air filter. I once changed to a genuine and the hum went away. Back to aftermarket now and the hum is back. You can test this by putting pressure with your hand on the air box whilst idling.

Thank you for your reply.

I also noticed this once I opened up the hood the first time I checked the vehicle, I changed the air filter from a random brand to a Bosch filter, and the shaking was gone but the sound I am trying to problem-solve was not.

[spot01]

Thank you for your reply.

* You are right about that the tensioner was replaced together with the airbag recall, I tried to call the workshop regarding it but they did not have any data if it had passed the test.

* Auto fluid has been changed at 178k, that was a service from aftermarket workshop and they told me it was changed. If it really has been done am i unaware of, maybe I should change it myself.

* The noise is more noticeable when the engine is cold.

I will see if i can make a recording of the sound and post it here.

The auto fluid is quite expensive as it must be the correct type, so I wouldn't change it unless you think it wasn't done or the wrong type was used? Ask them what brand & type of fluid was used. You should be able to check the colour & smell of the fluid via the filler (note this is a plug as these don't have a dipstick).


There is a separate page in the service handbook to record each time the fuel rails are removed to adjust the valves, although quite a few mechanics don't fill it out, making it unreliable unless it looks like they are all entered. If you know where the services were done they might be able to confirm the removals. I suspect many cars get to 180k without needing the rails replaced as the valves haven't been done 5 times before.

[rwnaas]

The auto fluid is quite expensive as it must be the correct type, so I wouldn't change it unless you think it wasn't done or the wrong type was used? Ask them what brand & type of fluid was used. You should be able to check the colour & smell of the fluid via the filler (note this is a plug as these don't have a dipstick).


There is a separate page in the service handbook to record each time the fuel rails are removed to adjust the valves, although quite a few mechanics don't fill it out, making it unreliable unless it looks like they are all entered. If you know where the services were done they might be able to confirm the removals. I suspect many cars get to 180k without needing the rails replaced as the valves haven't been done 5 times before.

As I am an importer of oil, that would not be any problem. I can change it to be secure, is it only a drain plug on bottom and a fill/level plug on the side? So I just drain the fluid and fill it up until oil comes out of the level/fill plug?

I could not find it in the service handbook, it's on Italian as well because it was imported in 2013..

[BruceandBobbi]

Wow. An Italian import in Norway.

[spot01]

As I am an importer of oil, that would not be any problem. I can change it to be secure, is it only a drain plug on bottom and a fill/level plug on the side? So I just drain the fluid and fill it up until oil comes out of the level/fill plug?

I could not find it in the service handbook, it's on Italian as well because it was imported in 2013..

I haven't done that task, but I think there is a procedure to follow.
Try here:

http://faq.out-club.ru/download/pajero_iv/maintenance/Service_Manual_2008_2013/2013/index_M1.htm

[rwnaas]

Wow. An Italian import in Norway.

Yes, not so often

I haven't done that task, but I think there is a procedure to follow.
Try here:
http://faq.out-club.ru/download/paje...3/index_M1.htm

Thank you for that, i will also try to make a recording of the sound.

[rwnaas]

Did a recording:

https://youtu.be/El_0PgC8HSs