2012 D40 TD cold start rattle and whooshing noise under load - looking for advise

[Julian199]

Hey folks, new guy here.

I've scoured the internet for many months now, on and off, for the issues I am having. I'm pretty sure I've seen most threads on these topics, I've watched pretty much every YT video by West Yorkshire engine services, so I'm
at my whit's end somewhat. I will write about my symptoms objectively and will then add how I approached them. (There will be a TL;DR)

History:

I bought a 2012 D40 Navara in 01/2021 in QLD, Australia. Thai built 6 speed manual, YD25 with just under 160 000km on the clock. She didn't come with any history, which makes my decision to purchase questionable,
but I did get second hand warranty and it was at the height of the terrible covid induced second hand car market. It is what it is now, anyways.

The symptoms:

Around two months ago these things became really noticeable to me, whether or not they were there from the start I can't really say.

-There is a intermediate/repeating whooshing noise when driving. It becomes particularly apparent at around 1800rpm upwards, but only when taking the foot of the throttle.
I would not describe it as a knocking sound, if it didn't occur in it's repeating nature I'd swear it was regular engine noise. The intervals become shorter the higher I rev the engine.
At around 2000RPM I get around 3-4 'wooshes' per second, not sure if that helps. I don't have the impression that engine temperature has any effect on the noise at all. It occurs through all gears and independent of vehicle speed, but only when moving.
I'm uncertain whether or not the sound is there when the car is standing still in neutral. If yes, it is so quiet that it's almost impossible to distinguish from all the other diesel noises going on.
I know this is a symptom that has been written about many times in various forums, but due to the difficulty of explaining a sound in writing I was never really sure if those issues were the same.
Hence me trying to be as detailed as possible.

-Cold start: Oil pressure light comes on for a couple of seconds when I start her up, and has always done that since day one. Around the same time as the previous problem (I think), I've started noticing a very loud, distinctive 'metally' rattle for almost the exact same time as the oil pressure light is on, (between 5-10 seconds maybe, but it does go away if I press the accelerator). I do normally just let it warm up a bit after starting cold, without pressing the gas and after those initial seconds the engine sounds fine.

-There has been a hand full of times when she stalled on me after cold start, especially after not having been started for a few days or a week. The stalling happens during the rough idle, again within maybe 5-10 seconds with the oil pressure light on. Each time I waited a second or two, started again and she ran fine.

Apart from that I haven't had any issues, warning lights or anything else.

Here are my own thoughts and my (unsuccessful history) of trying to deal with these issues.

1. I had it looked at right after purchase by an acquaintance at a Nissan dealership who was under the impression that there were no audible timing chain issues. It was just a quick sound check, he had a look around the engine bay but the car was warm too, so I'm not relying too much on that. Keep in mind this was at least 6 months before I ever noticed any of the above mentioned issues.

2. They say 'never google your symptoms' and that's probably true for your car as well. After I started noticing my problems I was pretty sure that the issues came down to a stretched timing chain or a faulty injector.
A mate at the time said he saw a bit of black smoke which made me think it might be an injector fault. On the other hand I didn't feel like I ever experienced any significant power loss.

3. I brought the car to a my mechanic who did a couple of small unrelated things (rear break shoes etc.) and found an exhaust leak, which he welded up. I figured that would have been part of the sound (at least the whooshing noise while driving) and he said apart from that the car is fine. At that point I thought the issues were all resolved, but he did add, that the timing chain was noisy when I left. I presume he knew the sound was still there and he knows I'm getting paranoid, so he was trying to give me comfort of mind.

At the end of the day the symptoms are still there and this is keeping me up at night -> Diagnose_11Mar14.pdf (yd25.com.au)

My assumption now is, that this is a timing chain issue, and that if not addressed will probably rip my engine apart. This is where I am a bit lost. I can have my mechanic quote a chain replacement or a duplex upgrade for me, but he doesn't seem to think this is necessary. Considering it's a big expensive job I want a bit more input before I throw money out the window. I live somewhat remote and while there are a few other mechanics around, there are long waiting times. The guys I see have a good reputation and have been around for decades, so while that doesn't necessarily mean they don't make mistakes, I'm not referring to my dodgy uncle with a torque wrench.
I should also mention that I have very little experience around serious mechanical work, although I wouldn't be averse to learning it.

I'm sorry for this massive post, I just didn't have the feeling that other posts regarding these issues went into enough detail to narrow anything down.

TLDR: My 2012 Diesel Navara D40 has a repetitive whooshing noise, only while driving (coming off the accelerator). There is also a loud, metal rattle for 5-10 seconds after cold start, along with a handful of stalls I have experienced, also only during cold start. After 'google researching my car troubles' (as you do) I am wondering if I am being paranoid or if it's sensible assuming that these are timing chain issues that will have a dramatic ending if I don't start putting money into fixing it.

 

[Old.Tony]

Welcome to the forum.

It actually sounds like you might have a couple of issues that need attention.

First off the bat: I'd look at the next oil change and perhaps do it sooner rather than later. Drive the car first to warm up the oil, add some engine flush that contains a high detergent component and follow its instructions (which will be "run the engine a bit more" ). Change the oil and use a good low-ash (and maybe even synthetic) oil designed for diesel engines (the oil itself has additional detergents in it). I'm thinking about this because the extended rattle may be due to oil not reaching the tensioners quickly, which might be an indication of a blocked oil path or even tensioners that have accumulated some residue causing them to get a little sticky. That's something you really want to avoid, because if the chain lets go, your engine will suffer catastrophic damage.

I'd also take a look at boost pressures. Either whack a mechanic's workshop analyser on and drive the car around so the noise is made, or get yourself a cheap bluetooth OBD adapter (ELM327) from eBay and grab the data from the ECU using an app like Torque (Android). Monitor the boost pressure - under very mild acceleration you shouldn't see over about 10-12psi, and it should peak somewhere around 21-22psi. You certainly shouldn't see much over that (and worse, it shouldn't ever go "negative" or read "vacuum" ). The sound you are hearing could be the turbo overboosting but we won't know until you've driven it with the data being monitored.

While you're monitoring the boost pressure, add a "fuel rail pressure" monitor. Drive the car down a hill and take your foot off the loud pedal. Fuel rail pressure should drop to zero. Does the engine still make the noise?

 

[Julian199]

Thanks for the quick reply,

I ordered one of those scanners and will get some engine flush as well. I should get the scanner some time next week, so I'll post my updates then.

I've heard people say that engine flush can lead to seals being exposed that were previously covered in grit and dirt, which might lead to leaks. Is that something you would be worried about?

I guess that concern makes sense for older cars with high kilometers, not sure where mine fits on that scale. Plus, a leak is better than a blown engine I guess

 

[[email protected]]

could you have 2 issues 1st air supply to manifold has massive leak disconnected etc (or at turbo) 2nd perhaps also your radiator fan is intermittent

 

[Old.Tony]

^ That raises something I've often forgotten about: cracked radiator fan blades. Have actually seen some cracked at the root, allowing the blades to flex a little more. Too much flex and that fan's going to eat the radiator.

But yes could be a boost leak too. Look for black oily emissions in the charge air hose (all of the hosing and intercooler and connections between the turbocharger and the inlet manifold).

 

[jerome4506]

I had a whooshing noise on my D40 and it was a split in the intercooler hose from the intercooler to motor caused lack of power and black smoke. The split was close to the radiator fan so presume the fan and positive air coming out of the hose were making the Whooshing noise.

 

[Julian199]

So a quick update here:
I will do a proper test drive including a
downhill stretch on the weekend and post any further findings:

I immediately noticed that calculated boost goes into the negative whenever I take the foot off the throttle.

Fuel rail never seems to dip below ~4500psi but I only drove a flat stretch for about 10min and let it idle for a bit at the end.

Pic is calculated boost

 

[ahtisham56]

So a quick update here:
I will do a proper test drive including a
downhill stretch on the weekend and post any further findings:

I immediately noticed that calculated boost goes into the negative whenever I take the foot off the throttle.

Fuel rail never seems to dip below ~4500psi but I only drove a flat stretch for about 10min and let it idle for a bit at the end.

Pic is calculated boost

View attachment 35995

Hi
I am also looking for j2534 scanner for my navara 2008, which scan is this?

 

[Scott52]

Like post #6 I had the whooshing noise and it was also the intercooler pipe. In my case one clamp on the short rubber hose joining piece that connects the metal pipe to the intercooler had slipped off. This joining piece is behind the grille on the passenger side.

As far as the timing chain goes the best way to find out if it's a problem is to have a look and measure the clearance between the chain side plates. Three years ago I had concerns about my timing chain so I removed the EGR pipe then the plastic timing chain cover. There are good instructions here: Manual Method

My concerns were warranted because some of the chain links were measuring 0.75mm compared to the service limit of 0.50mm. The guides were also worn so I bought the dual row kit from www.yd25.com.au.