Metallic Rattle Under Acceleration '14 Forester

[Daskuppler]

Hello Everyone,

 

I seek your advice, yet again.  I have a 2014 Forester with 115k on it and it has recently developed a metallic sounding rattle in the front end.  The best I can tell is it's coming from driver front, but it is a little hard to pinpoint.  The noise is only present right as the gas peddle is pressed and last for about a second.  It sounds very similar to the traction control system, but it is not activating.  I scanned for codes, and there are no codes (apart from the SRS code I have discussed in a previous thread, my scan tool can read all Subaru modules).

If it makes sense, the noise does not sound like it is internal to anything (there is no apparent dampening to the noise).  It's a little hard to explain, but the noise is very clear, it does not sound like it it is a CV join or anything else covered by a boot, or inside of another component.

Recent work which as been done:

New brakes and rotors all around (Powerstop Z26) Noise was present prior to this or right about the time of replacement.

Brake system flush (I did passenger front, driver rear, driver front, passenger rear).  I used Motul 5.1 fluid. Noise was present prior to this or right about the time.

Front wheel hub assemblies (Subaru OEM) Noise was present prior to this or right about the time.

Transmission drain and fill (5 qts of Subaru CVT II fluid was drained and filled with CVT temperature between 90 and 115 degrees.) The noise appeared about 5k after this.  One previous drain and fill was apparently done with Castrol CVT fluid.

PCV valve (noise was present before replacement).

 

The brakes and hubs were done all at the same time.

The engine also seems to hesitate/stumble periodically when taking off from idle.  This issues seems to have started or been greatly worsened after the CVT drain and fill.  Would it be beneficial to have the system flushed by Subaru since Castrol fluid was used for one change interval?

 

I did an oil change today using Motul 8100 0w-20 and a new oil filter.  This did not help the issue.

[1 Lucky Texan]

does it also happen parked?

seems like heat shields could be a possibility.

[forester2002s]

+1 on rattling heat-shields. Does the sound still appear when stationary in Parked mode?

The best (only?) way to check for loose heat-shields is to get under the car and shake the exhaust system to check for loose parts.

[Daskuppler]

1 hour ago, 1 Lucky Texan said:

does it also happen parked?

seems like heat shields could be a possibility.

It does not happen in park, only under load for a brief second and not every time (though it occurs more often than not).

[idosubaru]

Heat shield. Just the beginning so it's light and hard to find.

Does it do it when pressing the gas pedal to *maintain speed, but not accelerate*?   For instance when climbing a hill - the gas pedal has to be pressed further to maintain speed up the grade.  Does it do it then? 

Is it ever louder or softer or always the exact same noise no matter the speed? 

If you replicate the conditions that make the noise (pressing gas pedal a certain amount) - but do so while turning left and right - does it still do it?

Does it do it from a stand still, downshifting from any speed, when pressing gas to accelerate to pass or up hill? 
 

Have the engine or trans ever been removed?

[Daskuppler]

25 minutes ago, idosubaru said:

Heat shield. Just the beginning so it's light and hard to find.

Does it do it when pressing the gas pedal to *maintain speed, but not accelerate*?   For instance when climbing a hill - the gas pedal has to be pressed further to maintain speed up the grade.  Does it do it then? 

Is it ever louder or softer or always the exact same noise no matter the speed? 

If you replicate the conditions that make the noise (pressing gas pedal a certain amount) - but do so while turning left and right - does it still do it?

Does it do it from a stand still, downshifting from any speed, when pressing gas to accelerate to pass or up hill? 
 

Have the engine or trans ever been removed?

Turning does not make it worse or better.  If anything it is less prevalent when wheels are turned. 

 

Slight increases in pedal actuation do not trigger the noise (maintaining speed up a hill).  It does do it periodically when passing.

The noise is not always the same intensity.

To my knowledge, the engine and transmission have never been removed.  The car was purchased with 30k miles on it and was supposed to be clean, but I noticed when installing the lightbar a while back that the passenger side of the front bumper had been dented behind the plastic so I'm not entirely certain of the accuracy of the history/Carfax.

That being said, bringing up the light bar makes me wonder if something there is loose.  I'll have to check it this evening.

[idosubaru]

Does the "metallic sounding rattle" have any cyclical nature to it like it's something spinning or it's of random frequency or random vibration?

Heat shields are the most likely.  Usually due to damage from striking something, or rust. That's been said multiple times but you haven't commented on those. They're ubiquitous - I'd guess 50%+ of the 10 year or older vehicles around here have had loose heat shield noises.  There's more rust here but it can also be caused by striking debris, etc.

checking the aftermraket installed lightbar is a good thought. 

[1 Lucky Texan]

not a thumping? wondering about lower control arm's rear bushing.

[Daskuppler]

1 hour ago, 1 Lucky Texan said:

not a thumping? wondering about lower control arm's rear bushing.

Definitely not a thumping sound.  It's a very fast and brief metallic tap/rattle.

 

Is there a way I could check the bushings beyond a visual inspection?

[idosubaru]

27 minutes ago, Daskuppler said:

Definitely not a thumping sound.  It's a very fast and brief metallic tap/rattle.

 

Is there a way I could check the bushings beyond a visual inspection?

No, and a visual inspection will probably strike out if your symptoms are so light.  You'd need a pry bar and maybe to get the weight off the wheels. 

I'm pretty sure it's your heat shields since you keep ignoring those comments and questions.  lol

Is there a reason you've not responded to multiple heat shield mentions?

[Daskuppler]

8 hours ago, idosubaru said:

No, and a visual inspection will probably strike out if your symptoms are so light.  You'd need a pry bar and maybe to get the weight off the wheels. 

I'm pretty sure it's your heat shields since you keep ignoring those comments and questions.  lol

Is there a reason you've not responded to multiple heat shield mentions?

Haven't had a chance to look.

 

Best I can tell as of now is the the heat shields are good. One of the front plastic pieces on the undercarriage has had a few of the plastic clips pulled out. Pushing on the bullet results in a very similar noise. I ordered some clips/fasteners and will see if that fixes it.

[brus brother]

I have a 2008 OB with chronic, migratory and recurring heat shield issues. 135K miles in the rust belt.

Years ago when it first started, car was in for a free oil change at SOA. I always enjoy the up-sell conversation when in for the "free" service... "Sir, you are due for your headlight rotation. I see you have your kids in the car. You probably want to take care of this now." I always decline, telling them they are not my kids, so not my problem. Besides, I do most simple work myself and rotate the headlights as per manufacturers schedule of maintenance.

OK Back to the heat shield noise. The tech proceeded to bang around with his hand on the exhaust and once the noise was located (to my horror) he inserted a self tapping screw into the exhaust.

But what he actually  did was drill ONLY through the heat shield but NOT actually into the exhaust pipe, wedging the shield in place, eliminating the heat shield from rattling. Phew.

In the past I used stainless steel hose clamps (per USMB recommendations) where straight runs allowed but recently ran into a new loose heat shield on a bend that defied my attempts with a clamp.

Pulled out my nut driver and a self tapping screw and voila, NNM (noise no more.)

Sounds like OP may have figured out his noise but just wanted to tell an old timer's tale of yore.

Now, get off my lawn. ;-)

[idosubaru]

14 hours ago, Daskuppler said:

Haven't had a chance to look.

 

Best I can tell as of now is the the heat shields are good. One of the front plastic pieces on the undercarriage has had a few of the plastic clips pulled out. Pushing on the bullet results in a very similar noise. I ordered some clips/fasteners and will see if that fixes it.

Good find.

I’m not picturing how it’s mounted and it’s too hot to go outside and look but I’m wondering why it does it when pushing gas.  Seems like Undercover should be steering/incoming air direction or speed related not gas pedal related. Can’t picture any of those fasteners being connected to engine/trans mount that would shift under initial gas pedal torque.

Those plastic undercovers and clips get beat.  Clips often broken and missing. Hope that nails it. 

You might have good ears and a quiet car. I don’t think I’d have the luxury of noticing! 

Edited June 16, 2022 by idosubaru

[forester2002s]

I've noticed that engines twitch/move/jump when parked with the hood up.  A little surge of gas to raise revs causes this engine movement. It may only last a second .

This probably also happens when on the move, especially if the gas pedal is pressed down to speed the car up.

It doesn't take much to make the heat-shields make momentary contact with the exhaust-pipe. Rattle-Rattle!

[1 Lucky Texan]

I had a mystery noise for almost 2 years - turned out it was one of the bolts from after accessory belt change - I hadn't tightened it.

there's a product called Chassis Ears that might help with difficult noises.

Edited June 17, 2022 by 1 Lucky Texan

[Daskuppler]

I replaced about 4 broken clips and it did not resolve the issue.  I also noticed a rattling when the engine was started from cold (sounds like it's passenger side engine) followed by what sounds like valve chatter which went away after a couple seconds.

While driving around, I have noticed the noise seems to be most present when the engine hesitates which I have recently correlated to the oil consumption and puff of smoke.  Could this be valve chatter, poor oiling, etc?

[1 Lucky Texan]

hmmmm....maybe pull and compare plugs to see if a single cylinder is the problem and which one? maybe a 'dropped' valve guide or?????

[idosubaru]

7 hours ago, Daskuppler said:

I replaced about 4 broken clips and it did not resolve the issue.  I also noticed a rattling when the engine was started from cold (sounds like it's passenger side engine) followed by what sounds like valve chatter which went away after a couple seconds.

While driving around, I have noticed the noise seems to be most present when the engine hesitates which I have recently correlated to the oil consumption and puff of smoke.  Could this be valve chatter, poor oiling, etc?

Did you search for any TSBs or recalls? Some year FBs have broken valve spring issues. I think it’s just Impreza/Crosstek but I’d check. 

[Daskuppler]

11 hours ago, idosubaru said:

Did you search for any TSBs or recalls? Some year FBs have broken valve spring issues. I think it’s just Impreza/Crosstek but I’d check. 

All I am seeing regarding the engine is the oil consumption issue.  I'm going to call the dealership that performed the test and request a copy of their test since they told me the car did not burn a drop of oil while they performed the test.  After reading the service bulletin, they didn't follow the instructions so I'm hoping I can find a loophole to get a new engine since it is beyond my skill level to do that much work on this engine.

 

[idosubaru]

Can you have the oil test done again or at another dealer?

[Daskuppler]

On 6/20/2022 at 2:29 PM, idosubaru said:

Can you have the oil test done again or at another dealer?

I tried. SOA told be to pund sand, warranty expired at 100k or October 21,2021 whichever comes first. I'm past both....I called the dealership and asked for the vehicle's records.  I had to talk to a manager just to get them, but they won't do anything. They stand by their technician that the car did not burn a drop of oil during the test. They blamed it on a bad PCV valve which they replaced prior to the test.  I argued with them on at the time and they wouldn't do anything, apart from trying to hold the vehicle for safety issues because the brake fluid had gelled....which miraculously happened while they had the vehicle.

I'm still waiting for results from Blackstone but it looks like I'm SOL at this point. Subaru won't touch it, unless it's to work on it.

[Daskuppler]

This is Subaru's response:

 

Hi Andrew:

 

The vehicle is well beyond the terms of the warranty and our obligation to the vehicle has concluded. Subaru of America will have no further involvement. 

[GeneralDisorder]

I would have had just pulled the dipstick tube out of the pan and vampire pumped a quart of oil out of the thing for their stupid test. They want results.... no problem I got this. Hold my beer. 

GD

[Daskuppler]

2 hours ago, GeneralDisorder said:

I would have had just pulled the dipstick tube out of the pan and vampire pumped a quart of oil out of the thing for their stupid test. They want results.... no problem I got this. Hold my beer. 

GD

Hindsight is 20/20. I thought I had it in the bag with as much oil as I had to add. I did think about it at the time but didn't know if there was anything to prevent tampering.

 

What I wouldn't give for that little oil now.

We still have one EJ251 running strong at least.

[GeneralDisorder]

They usually paint mark the drain plug and put a tamper sticker over the dipstick - thus you unbolt the TUBE and lift it and the dipstick out of the pan and suck out an (alarming) amount of oil and then take it in. Instant short block replacement on Subaru's dime.

In no way is this an admission of having done this or assisted in doing this 

I'm ex-military. Someone says "Test" and my brain instantly starts down the path of how to rig the test. Especially when they send me out unsupervised...... all the tests in the military were open book. If you can't pass that kind of test you aren't trying at all. 

GD

Edited June 23, 2022 by GeneralDisorder