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Subaru Outback Diesel 5MT 2008
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Discussion Starter · #1 ·
I've owned my 2008 Diesel Outback for some months now, but there are still some things I don't understand.
  1. When driving 50-110km/h I sometimes get a high pitch, metallic clicking sound. It sounds like a loose screw, vibrating fast. It lasts for a couple of seconds, sometimes longer. Is this the DPF regen or the injectors calibrating? Should I look more into this?
  2. What does a DPF regen sound or feel like? How can you tell that it is happening?
  3. I also have some hesitation when flooring the pedal (to merge on the highway). It's like the engine is taking a one second timeout. This happens in the high rev range. I've heard about injectors being a bit wonky, could it be a fuel related problem?
FYI: My Outback was registered and probably made, before May 2008. Subaru had some crankshaft problems with their engines then. I've done 179000km without any engine problems.
I'm sorry for posting about my Outback here, but there isn't a diesel section on the outback forums. :(
 

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2012 Forester 2.0D 6MT
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33 Posts
No problem, I'm sure you'll get some help here.

1. That doesn't sound normal at all. Could you get a video/recording of it? It's not injectors calibrating - that happens at idle. It's not DPF regen - they typically only cause a slight but noticeable drop in power and sometimes a different exhaust sound.
2. See the previous. I know that some of the very early Subaru diesels in the EU have a totally passive DPF - no sensors and I think no regen process. But from memory they were only in the Legacy.
3. Does it reach the usual level of power after the hesitation? Has your fuel filter been changed recently? Try that first. It's not a difficult job to DIY. Some other possible causes are a seized EGR, clogged intake manifold, or VNT turbine vanes seized.
 

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Subaru Outback Diesel 5MT 2008
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Discussion Starter · #3 ·
No problem, I'm sure you'll get some help here.
1. That doesn't sound normal at all. Could you get a video/recording of it? It's not injectors calibrating - that happens at idle. It's not DPF regen - they typically only cause a slight but noticeable drop in power and sometimes a different exhaust sound.
I'll try to get in on video, but it happens somewhat rarely, so it may take some time.
2. See the previous. I know that some of the very early Subaru diesels in the EU have a totally passive DPF - no sensors and I think no regen process. But from memory they were only in the Legacy.
I don't know if I have a passive or active DPF. Any way to tell from looking at the engine? It's Euro 4L if that means anything.
3. Does it reach the usual level of power after the hesitation? Has your fuel filter been changed recently? Try that first. It's not a difficult job to DIY. Some other possible causes are a seized EGR, clogged intake manifold, or VNT turbine vanes seized.
It reaches it's usual amount of power after the hesitation. The car had a service 2000km ago, and the mechanic has swapped out the diesel filter. (But you never know with mechanics). EGR, intake manifold and VNT turboes sounds like a pain in the donkey, and way above my skills. For now, I just won't floor it.

Thanks for the help, I'll get the sound on video ASAP :)
 

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Subaru Outback Diesel 5MT 2008
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Discussion Starter · #4 ·
@notnothing

Success: I managed to record the sound.
Failure: My phone had a hard time picking it up.

Here is the sound. I tried to remove some of the background noise, but it isn't perfect. Neither is the quality.

Some more about the sound. It hasn't happened in 1st or 2nd gear, but it has happened from 3rd to 5th. It only happens when going up long hills or slopes. I used cruise control, so it had a steady throttle. It's more pronounced and "sharper" IRL, you won't miss it, but the phone picked up the wind and tyre noise instead :rolleyes:. I also met a guy with a clapped out, riced out, blacked out diesel Impreza when taking a break from all the driving. He said it might be one of the injectors, so I've already bought a can of Tunap 984.

Hopefully that might fix the hesitation problem, since that might be related to not enough diesel entering the engine. (And hopefully not something expensive)
 

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2010 Forester Diesel 6sp Manual
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203 Posts
Check out my post about mysterious rattle

After that I had one exhaust shield clamp rust off and that caused weird noises also.

Under load it could also be
Maybe dual mass flywheel? Clutch disc?
Try slightly press clutch next time, maybe the noise changes
 

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Subaru Outback Diesel 5MT 2008
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Discussion Starter · #6 ·
Check out my post about mysterious rattle

After that I had one exhaust shield clamp rust off and that caused weird noises also.

Under load it could also be
Maybe dual mass flywheel? Clutch disc?
Try slightly press clutch next time, maybe the noise changes
It stops the moment I press in the clutch actually. But that might be because the CC disengages. I'll test more and take a look at the turbo.
 

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Subaru Outback Diesel 5MT 2008
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Discussion Starter · #7 ·
Under load it could also be
Maybe dual mass flywheel? Clutch disc?
Try slightly press clutch next time, maybe the noise changes
You were right about the clutch stuff. I got the noise 4 times today. 3 times while doing 90km/h in 5th gear going up a long hill. And once doing 80km/h in 4th, also uphill. Pressing the clutch slightly, past the dead-point the noise would stop. I wasn't using CC, so I still had the throttle applied when pressing the clutch.
 
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