Elusive ticking noise from outside the engine.

[justflick]

I'm familiar with all sorts of ticking, knocking and tapping sounds- valves, rod knock, piston slap, bearing noises etc.. My '02 5spd legacy with 80k on it has been making a noise since I've had it that is entirely new to me though.

So here's the gist of it.
There is a ticking noise that only occurs under about 10%-20% throttle and when cruising.
The noise appears when hot or cold, and disappears when coasting down or accelerating even mildly.
Here's why I think it's not the engine internals -the sound is not constant at all and actually cuts out with an extremely regular pattern. Every 15 ticks or so, it disappears. Imagine hitting mute for a tiny instant 60 times per minute.
The sound is in every gear and exactly follows the engine RPMs. (shifting from 5th to 4th causes the frequency to bump up)
I'm thinking it's a solenoid of some sort.
Since the car only makes the sound when it's moving and at a very specific throttle position, it's been damn near impossible to investigate.
The reason I'm chasing the source so much though is that the throttle value that causes it happens to be exactly at cruising speed! I'm constantly having to vary my speed to avoid this sound and it's fairly maddening.

The video I'm attaching isn't the best since audio artifacts and road noise almost completely cover the sound. But if you listen closely at the 0:17 to 0:20 mark, that is the most apparent time in the video.
http://youtu.be/_lBOBcQ5alE

Ideas?

(recent work I've done with no effect good or bad: plugs, wires, TB, new idler pulleys)

[chuckthefuk]

Hmmm..

Have you tried to replicate the ticking noise without moving. As in letting the car warm up opening the hood and revving the throttle?

Is the noise still there?

I am trying to figure out if its a mechanical rotational issue from your drivetrain or specifically the motor.

I'll toss out some suggestions..

1) Sometimes the timing belt tensioner 'bracket' is damaged.. bad threads or broken bolt. This would cause a ticking/banging since its hitting the drive side head. Its usually noticeable at idle but you never know.

2) Valve's need to be adjusted.. Lots of DIY for it or have a qualified mechanic adjust it for you.

...

Just to double check.. you are not throwing any codes? no CEL/MIL? I watched the video and your cluster looked fine.. but have you experienced any issues in the past?

-Chuck

[justflick]

Thanks for the input. When I figure this out I'll most definitely post my solution in case other people are searching with similar symptoms.
Anyhow.
I've tried getting it to tick in the driveway and have never managed, even if for just a split second.
OBD says there are no active or pending faults and all self monitoring tests have been completed. (everybody with >$100 of tools should own an ELM32 unit. They're amazing!)
When I bought the car, it was occasionally misfiring/stumbling but I cured that right away with new plugs and wires. The plugs weren't terrible but I think the dielectric on the wires was well past expiration.

It really is an odd thing. I would think without a doubt that it was a worn sleeve bearing if it was a constant tapping when cruising.
As long as it's not a terrible idea for this type of motor, the next best troubleshooting step I can think of is to disable each cylinders' plug and injector one at a time, take it for a drive and see how it reacts.

[chuckthefuk]

Well the problem with that is if you cant replicate the problem in your driveway then how do you expect to narrow it down by just pulling the wires..

....

I want to blame the CV or Driveline or Brakes.. but its iffy.. I read your other posts describing this issue on those other subaru forums...

Maybe someone can chime in..

-Chuck

[justflick]

My line of thinking is that if I drive the car on cyl #'s 234,134,124,123 and the ticking disappears for only one combination, then there is at least that much less searching to do.
I wouldn't call it impossible that the problem is between the clutch and output shaft of the transmission. At this point it's still a broad search so thanks.
And yeah, you caught me cross-posting to legacygt.
I've only had this car for about three weeks and was still shopping for an active forum that didn't include everything under the sun.
SL-i seems more relevent to my car so I think I'll be staying put :D

[justflick]

After about 5 sessions of troubleshooting, I caved and took it to Subaru for diagnosis.
Their response "It's not internal to the engine, and we have no idea what it is"
$90 is worth knowing that an engine swap isn't necessarily around the corner, and at least I know that far more experienced techs can't figure this out either.
I hate saying it, but I think I'm just going to learn to ignore the ticking.

[Garrison]

You could always try seafoaming it. It silenced the lifters in my 300z, and it helped out my suburu's idle considerably. At the very least you aren't doing any harm to your car by doing it *(Assuming you pour it in slowly and don't hydrolock your engine)*

[Huffer]

Stupid question - does it only happen when the wheels are turning?

Might be the ABS tone wheel.

[Hinyo]

I HAVE THE SAME PROBLEM!!!!! let me know if you guys figure it out

[justflick]

I actually did run about a half can of seafoam in through the intake about a week ago. It seems to have quieted the cold clatter a bit, but the problem I'm chasing down is still unfazed.
As far as it being an issue with the ABS, the techs suspected the transmission until they put the car up on a lift and spun the wheels up to find no hint of the noise. Somehow, it only appears when the car is *actually* moving. I wouldn't call ABS totally ruled out since they tested the car with the suspension unloaded which I suppose could change the thing they are testing.
In about a month I hope to pull the heads since the gaskets are seeping oil, I think that will be a good time to give the intake manifold a good inspection and cleaning.
haha maybe the next step is to throw the car on a dyno for an hour.

[TGX4776]

I had the same problem and it turned out to be loose heat shielding above the exhaust.

[justflick]

welp, It seems that Chuckthefuk was on to something thinking it was the driveline/cv/wheelbearing.
I was also wrong in thinking the the ticking tracked the engine RPMs as it's obviously 100% locked to wheel speed.
After being told by a Subaru tech that the engine is fine, I figured It was safe again to thrash the motor a bit.
at about 5500 RPMs in third gear while climbing to highway speeds, I heard a clunk and the ticking instantly became louder as well as more persistent. In addition to being louder, it happens outside of the light throttle zone that it was restricted to before.
In fact, I put the car in neutral and turned off the engine at about 20mph and the sound did not disappear. (abandoned lot)
I suspected the viscous coupling until I drove in tight circles with no effect.
My list of places to look is now the front diff, crown wheel/pinion, CV and wheel hub.
Before it was hard to tell exactly where it came from, but now it is clearly slightly to the right side of the transmission.
Coasting in gear causes everything to go 100% quiet.
Coasting in neutral causes the sound to become very obvious with the clutch engaged or disengaged.
I really hope it's not an internal transmission issue. The fact that neutral causes the sound makes me hesitant to think it's the CV or wheel hub but it's not impossible either.
[bummer]

[justflick]

I put new gear oil in and the noise is about 80% quieter. The oil level was touching 'F' prior to all of this happening.
There weren't any chunks stuck to the drain plug, just the usual grey goo.
At any rate, I think I'll have to baby the car and start saving for a used transmission. It seems if you're patient and can wait for a deal, they are quite a bit cheaper than I'd thought.
At least it isn't the engine :D

[chuckthefuk]

$250 can have you a gently used replacement.. lots of part outs / for sale threads.

Glad to hear its not the motor...

Good luck
-Chuck

[Dead91silvia]

When I watched the vid, I instantly thought it was like a leaf of something stuck somewhere... haha...

Depending on what on what part of the trans has the problem, it could last a long time. It might just be that you have a binding coming off of a CV joint also, but if you changed the fluid then maybe not... Still really odd though...

[sacharc]

Could it be shifter related ?
I have a similar problem but really less noisy.
Check out this video (not mine)
http://www.youtube.com/watch?v=d5ysGJFjzC8

[justflick]

Not only is the car still going, I have enough money stashed that I figured I'd quit babying the transmission and just put it out of it's misery already.
I did a bunch of 0-80mph pulls, shifting near redline, **AND THE SOUND IS GONE**(?!?)
It's down to about 5% of it's original level. It's so quiet now that I can't tell if the sound is actually there or if I'm just searching so hard to hear it, that I'm imagining it.
I'm still hanging onto that transmission fund, because, why the hell not, but seriously I thought I'd get to see the transmission grenade after how loud it used to be.
(disclaimer: I don't recommend Italian tune-ups for transmissions unless replacing the whole unit is an option you're cool with)