Uphill engine clanking sound 1996 Legacy ej22

[rendoll911]

The car: 1996 Legacy, 90,000 miles, 4EAT transmission, new plugs at 60k, new fuel filter at 70k.

 

Symptoms: Loud metal on metal clanking sound when driving up steep hills. The sound is like the sound of a crinkling can but repetitive.  Only happens up hills when RPMs are slowing because of increased load from road grade steepening. If I let up on the gas the sound stops and if I floor it and the transmission shifts down the sound stops. The sound is audible with the windows up and is very loud. It sounds like the engine is going to fall apart!

 

I just bought the car and used 87 octane on the first fill. The second tank i used 93 octane and am still getting the sound when pushing a bit uphill.

 

Anyone have any idea?

[johnceggleston]

first guess flex plate.

 

where is the sound coming from?

front?

left?

right?

center ?

under your seat?

[rendoll911]

It's hard to tell exactly because the noise can only be produced while driving, but I would say it's central under the hood.

[rendoll911]

The car is also leaking transmission fluid and oil where the engine meets the transmission, and leaking oil from under the timing belt cover.

[forester2002s]

Knock-sensor failed?

And ECU not preventing pre-detonation?

Result: 'Pinging'?

[idosubaru]

front differential:

1.  check fluid level and color/condition

2.  drain the fluid and check for chunks

 

front axles - the inner joints specifically.

1.  are the boots broken?

2.  do they look recently worked on?

 

the newer style timing tensioners can fail, causing a very loud rapping/metal/metal sound which sounds like rod-knock sort of.  yours should be the old style - but they're easily swapped/converted and maybe the old sytle can fail in a similar way, i've never seen it so not sure what the older styles do when they fail/loosen tension.

[rendoll911]

front differential:

1.  check fluid level and color/condition

2.  drain the fluid and check for chunks

 

front axles - the inner joints specifically.

1.  are the boots broken?

2.  do they look recently worked on?

 

the newer style timing tensioners can fail, causing a very loud rapping/metal/metal sound which sounds like rod-knock sort of.  yours should be the old style - but they're easily swapped/converted and maybe the old sytle can fail in a similar way, i've never seen it so not sure what the older styles do when they fail/loosen tension.

The front differential gear oil is clear and full according to the dipstick, I won't have a chance to drain it for a few days though.

 

The front axles are new and the boots are in good shape

 

The timing belt was just replaced by the previous owner, I assume the timing tensioner and pulleys were replaced as well, but maybe not. The mechanic did not replace the cam seals which are now leaking, so you can never be sure. 

 

Could oil leaking on the timing belt cause it to slip/ lose timing?

[rendoll911]

Knock-sensor failed?

And ECU not preventing pre-detonation?

Result: 'Pinging'?

There's no code/ check engine light. Wouldn't the ECU notice a failing knock-sensor?

 

The only code i have is the dreaded torque bind AT code which happens intermittently 

[johnceggleston]

 

I assume the timing tensioner and pulleys were replaced as well,

this cam be dangerous  .

most folks don't.

but since your car is should be non-interference it matters less.

[idosubaru]

The front differential gear oil is clear and full according to the dipstick, I won't have a chance to drain it for a few days though.

 

The front axles are new and the boots are in good shape

 

The timing belt was just replaced by the previous owner, I assume the timing tensioner and pulleys were replaced as well, but maybe not. The mechanic did not replace the cam seals which are now leaking, so you can never be sure. 

 

Could oil leaking on the timing belt cause it to slip/ lose timing?

 

those are inconclusive and maybe even suggestive of issues:

 

1. aftermarket axles are horrendously problematic.  high percentage of failures, an aftermarket axle with issues is the norm, not weird at all.

*I wouldn't be surprised at all if your issue ends up being the new axles. 

 

never replace original subaru axles - always reboot them.

if you need axles buy used SUbaru axles (www.car-part.com) and reboot them.  've only been getting 2-3 years out of aftermarket boots and now lean towards Subaru boots which last considerably longer than that.

 

2.  gear oil being "clear" or "new" could be new because a prior owner was hoping to mitigate a known differential issue.

[rendoll911]

 

those are inconclusive and maybe even suggestive of issues:

 

1. aftermarket axles are horrendously problematic.  high percentage of failures, an aftermarket axle with issues is the norm, not weird at all.

*I wouldn't be surprised at all if your issue ends up being the new axles. 

 

Would the axles make noise going in a straight line though? I always thought bad axles usually made noise when turning.

Edited August 14, 2014 by rendoll911

[scrap487]

Would the axles make noise going in a straight line though? I always thought bad axles usually made noise when turning.

 

I've never needed to work on the axles of ej series cars as I've only owned one, but in the 80s generation of subies, they do tend to make a lot more noise turning if the outer joint is bad, but both turning and putting a load on the car will cause them to make noise.  One thing you could try is to firmly grab hold of the axle and see if there is any movement up/down/front/back, if it's really bad I think you'll discover noticeable play(some side-side movement may be normal, but I can't say for sure). 

 

Is the sound reproducible with the vehicle not moving? IE, starting from a stop up a very steep grade, or giving it throttle while holding the brakes to keep the car stopped(should go without saying, but careful where you do this if you aren't familiar with the power of the brakes or engine).

[idosubaru]

Would the axles make noise going in a straight line though?

 

Yes, that is classic subaru front axle symptom.

 

 I always thought bad axles usually made noise when turning.

that is only a symptom of the outer CV joint.

 

warn inner joints vibrate under load (acceleration/steep grades).

 

Also - since they're aftermarket, they can fail in any way imaginable.

[rendoll911]

looks like the CV axles are rebuilt subaru axles (green inner hub) so i don't think that's the problem. Also, the tire doesn't wiggle when i manually torque it with my hands.

[Fairtax4me]

It's pinging. It may be running too lean, or the rings are worn and its burning oil.

How old is the fuel filter? How old are the spark plugs? How old is the PCV valve?

[rendoll911]

It's pinging. It may be running too lean, or the rings are worn and its burning oil.

How old is the fuel filter? How old are the spark plugs? How old is the PCV valve?

 

fuel filter is 20k / 7years old, spark plugs are 30k/11years old, and I have no records of the pcv valve being changed ever.

[rendoll911]

maybe ill start with with replacing those things, can't hurt

[idosubaru]

JCE's first guess of a cracked flexplate is starting to sound likely.

[rendoll911]

Is there anyway to check the flexplate without taking out the engine or transmission?

[rendoll911]

I read this somewhere on the internet:

 

"there is a bushing in the end of the torque converter that holds it centered on the input shaft of the trans. If this bushing was worn out, there would be trans fluid pouring out of the front seal of the trans"

 

I am losing AT Fluid and its not coming from the power-steering. It's also not pouring out, but I believe it's coming from the area where the transmission meets the engine. This leads me to believe I have a worn bushing which is leading to the possible flexplate noises. Could the bushing at the end of the torque converter leak just a little?

[Fairtax4me]

I'm not sure which bushing theyre referring to. The input seal for the transmission doesn't typically leak unless the torque converter was removed at some point.

Regardless of the leak, the flex plate isn't affected by a leak.

 

If the flex plate is the problem you will be able to replicate the noise by putting the car in drive, apply the brakes hard and the parking brake and hit the gas. This puts a similar load on the engine to accelerating. Make sure there is nothing in front of the car when doing this.

[brus brother]

I'm not sure which bushing theyre referring to. The input seal for the transmission doesn't typically leak unless the torque converter was removed at some point.

Regardless of the leak, the flex plate isn't affected by a leak.

 

If the flex plate is the problem you will be able to replicate the noise by putting the car in drive, apply the brakes hard and the parking brake and hit the gas. This puts a similar load on the engine to accelerating. Make sure there is nothing in front of the car when doing this.

Well, that's a lesson that doesn't need to be learned the hard way!

[idosubaru]

The Torque Converter Seal is leaking.  A fairly rare failure on Subaru's but it can happen as it's just a seal. I would expect it more from a car that had an engine or transmission swapped previously.

[rendoll911]

I'm not sure which bushing theyre referring to. The input seal for the transmission doesn't typically leak unless the torque converter was removed at some point.

Regardless of the leak, the flex plate isn't affected by a leak.

 

If the flex plate is the problem you will be able to replicate the noise by putting the car in drive, apply the brakes hard and the parking brake and hit the gas. This puts a similar load on the engine to accelerating. Make sure there is nothing in front of the car when doing this.

Great, thanks. I'll try this tomorrow.

 

[rendoll911]

tried accelerating in D with the brakes on but couldn't reproduce the sound. Another thing, there's no sort of engine performance loss when the sound occurs.