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No longer Saab newbie; have had the 2002 9-5 2.3t about 10 days now :)

Being used to very quiet, luxury cars and with my hearing pretty sharp, I am bothered by a resonant sound, aka low frequency hum occurring when (auto) transmission is engaged.

Car at standstill, engine warm and running, foot on brake, transmission in DRIVE. No error codes. Car meticulously maintained with logs. Acquired at 111 Kmi. The resonance never occurs with car in motion.

To verify I tapped a mechanic who owns exactly the same car with only 70 Kmi. That car exhibited exactly the same noise with tranny engaged. Owner stated he had never notice the hum.

Based only on two samples it appears characteristic to this MY. On the other hand, a 2010 93 was absolutely quiet under similar conditions.

Bothers me!!
Thoughts from the gurus here?

Thanks
 

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Hi, my 2006 Aero aut sedan does the same noise/hum that is supposed to be normal according to more experienced Saab mechs/owners... however I am convinced there is something worn out, maybe engine/trans mounts? Otherwise the car is quiet, once I select N in stop the drone is gone instantly, select D and its there (car is not moving, brake depressed).
Any ideas?
 

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mine has always done it to an extent, and like Hanz said, from all i've gathered it's kinda a saab thing...

i did make mine less of an issue by replacing the transmission torque rod mount and torque arm mount under the transmission.

also fixed up a few "vibrations" here and there to keep things still while the car was doing it's thing. the biggest culprits were window seal guides in the door that fell out and let the window vibrate if it was down at all, and my front door speakers that just kept shaking their bolts loose until i finally wised up and used a little locktite on them.

but i know what you mean it's so weird because as soon as you put it in neutral it's like perfect.
 

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When you say the hum goes away when the car is in motion, can you just take your foot off the brake and let it roll, at whatever speed it does in Drive in idle, and the hum is gone, or do you have to get on the gas?

It could be that changing bits of the exhaust system would cure the hum/resonance. Or changing the engine mounts.

As another question, is there a pulley in the middle of the serpentine belt when you look at the engine from the top? The belt should go under the pulley in a V-shape. If that pulley is missing ("short belt mod") then the belt might be making some noise/vibration. Not all 9-5 came with the middle pulley, but your 2002 should have.
 

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Subframe bushings also play part in that issue. If they're really worn you'll get some pretty good resonance when stopped in gear. If the vibration changes when you move the steering wheel while stopped then you can be pretty sure that at least your rear bushes are shot.
 

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also fixed up a few "vibrations" here and there to keep things still while the car was doing it's thing. the biggest culprits were window seal guides in the door that fell out and let the window vibrate if it was down at all, and my front door speakers that just kept shaking their bolts loose until i finally wised up and used a little locktite on them.

but i know what you mean it's so weird because as soon as you put it in neutral it's like perfect.
Can you go into more detail about how you applied the locktite to fix the door speaker noise? Which locktite glue did you use? Where did you apply? Any tips?

Thanks
 

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Can you go into more detail about how you applied the locktite to fix the door speaker noise? Which locktite glue did you use? Where did you apply? Any tips?

Thanks
basically what i did was once i figured out it was the speakers (there was a time when fixing the window issue i had the door card off about 5 times in 10 days and each time the speaker bolts had worked their way loose again) i got some loctite blue (i think the "number" is 242) put some of that on the speaker bolt threads and put them back tight. they have not come back out since then i don't think - i just know i hear no vibration from them in that area. and if you have loose ones you know what i am talking about.

the saab seems to vibrate a lot and certain things - like those speaker bolts kept coming right undone in a matter of days. the blue loctite works great on a bunch of places you might not consider - and you can still take the fasteners out when you want to also.
 

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The vibration usually goes away if you put it in neutral or up the RPMs very slightly. Changing the three easy to get to mounts did not improve my vibration all that much. My rear motor mount appears to be in fine shape but there have been some here for whom replacing it helped their vibration.

It's a 4 cylinder Saab quirk. You want smooth and quiet as a top priority getting a 6 cyl. of any make would serve you better.
 

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Subframe bushings also play part in that issue. If they're really worn you'll get some pretty good resonance when stopped in gear. If the vibration changes when you move the steering wheel while stopped then you can be pretty sure that at least your rear bushes are shot.
^ This!

what an amazing difference new subframe bushings made on my 03. no more shuddering or resonance and much better handling.

I should have done it long ago, but I was dreading the job
 

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I agree with those that mention the subframe bushings. My 02 has new bushings and new rear mount, the 03 is all original with 82k and there is a big difference between the two.
 

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ThIt's a 4 cylinder Saab quirk. You want smooth and quiet as a top priority getting a 6 cyl. of any make would serve you better.
Well I do come from the Inline6world however I feel it's not the way it left the factory, no one would buy a premium car that drones at lights all the time. To change in N to avoid headache is not an option for the tranny in a long run either. I will replace those s-frame bushings, I thing they have done just the 2 rear ones.
 

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I will replace those s-frame bushings, I thing they have done just the 2 rear ones.
If you do them do all 6. The job is huge, the parts are cheap. (I'd replace the rears even if you think they may have been replaced but don't know for sure)
 

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Vibration and/or hum?

All the 9-5's I've owned all exhibited some vibration at idle in D. Granted, some exhibited more vibration than others. Changing the transmission mount on one with excess vibration did not really yield any change. All the other mounts were in good condition, so as others and my SAAB shop have said, it is likely the subframe bushings. I have never completed the process because it is quite costly, and I usually end up putting money towards something else!

Unless the vibration is REALLY bad (which would warrant a look at your top engine mounts) you need to look at the costly subframe bushings).

http://www.saablink.net/forum/general-9-5-posts-information/59123.htm

BTW, I've realised from my most recent 9-5's a noticeable hum from the AC is usually always present.
 

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my o6 edna does the same! if i know the light will be red for a while i put it in neutral, with the weather i have never been under the car ever to check it since i bought it, is there a way to check for subframe bushing play?
 

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I have never completed the process because it is quite costly, and I usually end up putting money towards something else!

Unless the vibration is REALLY bad (which would warrant a look at your top engine mounts) you need to look at the costly subframe bushings).
.
Bad bushings will also cause your car to eat tires since the whole front end doesn't stay straight on the car when it's driving but shifts around. Seems especially hard on the inside edge of the front tires
 

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Bad bushings will also cause your car to eat tires since the whole front end doesn't stay straight on the car when it's driving but shifts around. Seems especially hard on the inside edge of the front tires
I've never had as much of a problem with front tyre wear. For me, the rears always wear out quickly as a result of springs and/or shocks and/or the rose joint bushings on each of the cars. In saying that, still not huge wear and I tend to get a reasonable life by rotating the tyres. I guess it long-term it would pay to look at all the bushings.
 

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You can turn up/down idle speed (+/- 50 rpm at 10 rpm steps) when trans is on D with TECH2.
 

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Drone changes when turning the steering but not much. I am fixing other issues at the moment, I will come back with result (I hope).
Raising the idle is not a solution, I am writing about a lot of drone, not a R4-I6 comparison/complain:)
 

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Steering wheel seems to vibrate to the same Aero beat so I dare to assume that more rooten eggs are in the basket :-/ Just getting Lpg conversion done at the moment, I will hopefully fix the rest during weekend.
 
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