grinding noise when engine braking

[sgould]

I would only use genuine Saab parts on labour intensive jobs.  There is still a two year parts and labour guarantee with genuine parts, if fitted by a VAT registered garage.  I think that's the requirement.  Maybe need to check again.

[Audax]

I would only use genuine Saab parts on labour intensive jobs.

It's something that was insisted on where I worked, the exceptions would be for a few cases, where the Saab part was unavailable and no availability date was set, where the Saab part was a few hundred percent more than the non-genuine and it was an older cheaper car, trim/accessories (we also might offer cheaper alternatives with older cars for things like air filters and pollen filters for example). Otherwise, all engine and mechanical parts would either be genuine Saab items or the same item from the OEM who originally made them for Saab.

It was notable how many cars would come in to us that had been to other garages where they couldn't fix a fault and they'd used (cheaper) non-genuine parts which when removed and replaced with the real deal fixed the problem.

[fka]

believe me, any of the major parts I've replaced or have had replaced, have always been genuine Saab, OEM or good quality aftermarket (Maptun exhaust for eg.). I went to the bother of sourcing a genuine Saab intermediate shaft, carrier bearing and tripod bearing, rather than replacing the whole offside with a decent used part or god forbid a q-drive shaft from ECP.
Why on earth I thought it was a good idea to scrimp on this, god only knows.

Anywho, the guys at my local Saab garage have given me a very fair price to fit another for me. This time they're supplying the part, GS, with (as you said sgould) parts AND labour warranty!

 

[fka]

For the sake of anybody following this...

Looks like the exhaust is causing the noise I'm hearing under engine braking. Attached is a picture of the hangers on 3" Maptun downpipe and their proximity to the corresponding hangers on the subframe.

You can see a rub mark on the hanger on the subframe. Also the bracket that attaches to the engine block and holds the downpipe (Same locating point for the bracket that attaches to the turbo.) had come lose. It wasn't lose when I checked the other week, so I assume it's been shaken lose by the downpipe hanger hitting the subframe.

I've tried a little gentle persuasion today to bend the hanger out of the way but I think a little fettling of the exhaust is needed to get a decent bit of clearance..

BTW - all the oil you can see in the pic is the remnants of the contents of my power steering fluid reservoir :/

[phoenix]

Nice find... and I think the most likely cause 

[fka]

I'd love to agree, however post applying a little bendage and getting good clearance (see attachments) there is still a notable but again reduced rattle. I think I've been dealing with more than one thing knocking it's self silly.. Next culprit is the offside CV. There's end to end play in the drive shaft. So either the CV has had it (unlikely as there's no clicking etc when turning.). Or the circlip that holds the shaft fast in the CV is missing/ failed and the shaft is rattling about - most likely ..

Either way and the most obvious conclusion, there be too much poly under the hood and not enough rubber!
Think I'm going to go back to a standard mount on the upper offside mount and keep the transmission mount poly, rather than spend and eternity chasing annoying rattles ..

D

:-)

[fka]

Still hammering away at this one !

I'd been dealing with increasing vibration through the steering wheel whilst under load. As I'd not touched my nearside drive shaft but couldn't actually see much wrong with it whilst on the car I decided to change it for a good quality second hand part from simply saab for around £50. Relatively easy job that took me about an hour including refilling the trans' oil.
At the same time I stripped down the outer CV on the offside, cleaned it, re-greased and fit a new boot (I swear getting the ball bearings back into a CV was complete ballache - literally!). The only problem I could see with the nearside shaft was a little play between the inner driver and tripod bearing and, once stripped down, two hairline cracks running through the cage that holds ball bearings in place in the CV.

Much to my dismay I also discovered a huge amount of play between the offside inner driver and tripod bearing. I replaced the intermediate (half) shaft with a genuine Saab part and (stupidly) fit a OEQ (Swedish manufactured) tripod bearing from a well known supplier (Who I'm still to give the change to offer me some form of recompense so wont mention them just yet.). I'd had enough for the day so packed up and went for a test drive. Surprisingly the vibration was reduced, so at least I was going in the right direction ..

Tackled the offside inner driver last week. I was convinced the inner driver must still be in a good state and it was just the cheep tripod bearing that was at fault. No such luck! My brand new intermediate shaft, with less than 3k miles on it is now trash with three lovely little pits where the bearing runs .. ! Having not expected that at all I removed the OEQ tripod bearing, which simply "fell" off the drive shaft splines once I'd removed the circlip! There was play between the drive shaft splines and the bearing! One very poorly manufactured part - be warned - buy genuine saab parts!

So for the time being I took the tripod bearing from the nearside and popped it on the offside, repacked with grease and fit a new boot. Despite the wear on the inner driver, the old tripod has again removed a lot of vibration but it's still not 100% and I still have a grinding noise when engine braking.

I'm back to the fact I have end to end play of the intermediate drive shaft. Have a look at the short video clip I've linked below. It shows that this play is the carrier bearing moving in the carrier bearing bracket. The bearing should be pressed in tight to the carrier and the shaft pressed into the bearing and held with a circlip.
Simply the carrier bearing bracket is worn. I believe (hope) this is the source of my grinding noise. And most likely partly to blame for the rapid deterioration of the offside inner driver. The remainder of the blame going to the poor quality, ill fitting tripod bearing.

Again have just ordered a complete offside driveshaft with carrier bearing and bracket from simply saab. We'll see how it goes. However if I'd followed the advice I'd received from my local saab specialist many moons ago and not bothered fitting individual new parts and had just replaced the complete offside shaft with a good second hand part, when it originally showed play in the carrier bearing, I'd have saved a lot of time and effort .... you live and learn!


https://dl.dropboxusercontent.com/u/65386929/2014-08-22%2012.19.01.mp4

[fka]

Thought I'd best follow up on this, plenty of people have viewed and I know how irritating it is when you find a topic that appears maybe covering something of use, you read all the posts and the topic just tails off with no follow up or answer ..

We I'm afraid I still can't give a definitive answer :-)

I've replaced my complete offside drive shaft with a used part from simply Saab so the vibration under load issue is now sorted. I can't believe the state the brand new genuine Saab intermediate shaft was in (very obvious pitting where the bearing rides.) and how much play was evident in the new genuine Saab intermediate bearing after such a short time on the car. Was it fit incorrectly or just a poor quality part? I Really don't know.

Was a little annoyed with the offside outer CV boot failing on the used part a day after it was fit. I'd had it in the back of my mind to just replace both boots before it went on the car but they looked to be in a good state and I've had (fingers crossed) no problems with the nearside used shaft I'd got from simply saab.
Was even more irked to be told by Simply that their 6 month guarantee didn't cover the boots! The least they could have done was send me a replacement boot, which would have set them back a whopping £10.
Anywho CV removed, cleaned and a new boot fit today ..

Back to the point of the grinding noise ... It wasn't the intermediate bearing .. I'm back to my original find of the hangers on the Matptun 3" downpipe hitting the subframe.

Whilst the car was on stands today I took a blow torch to the hangers and bent them well out of the way. Also retorqued the 'exhaust manifold to turbo' nuts which had slackened off a little.
A quick test drive showed that it certainly seemed to have improved the issue but I'm reluctant to call it solved as the rattle gets worst once the car is fully up to temp after a lengthy spirited drive.

Question - If it's the exhaust moving up towards the subframe under engine braking, shouldn't that movement be restricted by the rear lower engine/gearbox mount?
I tried placing a jack under the trans today with a block of wood to see if there was any excessive movement and managed barely half an inch of lift. At which point the exhaust was still well clear of the subframe ... Considering fitting the TDi mount ..

Rest of the car is absolutely spot on at the moment. I've now got polly bushes all round on the suspension, finally fit the rear bushes the other week which were a bit of a ball ache. I've even changed the inner tie rod bushes for black polly, which has made a huge difference to the steering. Tramlining is vastly reduced and torque steer is as good as none existent. Blood shame I had to order them from the States as I couldn't find them in the UK .. Don't get me wrong, the ride is hard but handling is as tight as gnats ch .. you get the idea

Had the wheels done in a lovely graphite by PX wheels the other week, they look great with the cosmic blue
Might put some pics up at some point.

To Do list -
- Had a very reasonable quote from a local Saab garage to have repaired the small but growing rust bubble on the offside rear arch.
- Have a small (not yet dripping on the driveway.) leak from the bellhousing. I believe its from the trans side (input shaft seal?). No clutch slip yet but will keep an eye on it and at some point have both the crank and input shaft seals done ... shame I didn't think about that when I had the viggen clutch and new slave fit .. c'est la vie

Should probably change the title of this post to "Grinding noise as 9-3 eats time and money .. " Well worth it though

take care
D

[Audax]

Question - If it's the exhaust moving up towards the subframe under engine braking, shouldn't that movement be restricted by the rear lower engine/gearbox mount?

Not sure, but, if the exhaust clearance is tight anywhere once it gets hot it will expand a reasonable amount, are you sure it isn't a shot engine mount and a hot exhaust finding something to rattle against?

[fka]

That's what I'm thinking but the mount doesn't look too bad. There's what looks likes a little bit of old oil at the top of the rubber but I'd expect to see quite a lot of hydraulic oil loss if it was totally shot.
Either way I'm considering fitting the tdi mount at some point..

[fka]

Not sure, but, if the exhaust clearance is tight anywhere once it gets hot it will expand a reasonable amount, are you sure it isn't a shot engine mount and a hot exhaust finding something to rattle against?
[/quote]

Still going on this one  ..

I noticed recently my only original engine mount (rear) had started spewing oil and there was quite a noticeable tilt forward and back motion of the motor when I had the Mrs hold the break down and let of the clutch in various gears (Slight fear for my life but you'll be glad to hear I came out of it in one piece  ) and I could see oil oozing out of the mount.

I replaced with a good quality OEM part from ECP yesterday. I've gone poly on the the trans and right hand mount but thought it best for comforts sake keep that one rubber.
You can see below, it's not as bad as some others posted on the web.

Handling is again noticeably improved, bizarrely powering out of a corner is now a total pleasure rather than a slight worry, the car pulls out beautifully. I say bizarrely since I would have though cornering would be affected more with shot trans and right hand mounts as they're keeping the motor central??

I also did some more fettling of the 3" Maptun down pipe and am sure it's now well clear of any possible fouling.

Anywho I still have the grinding noise whilst engine braking, which is now also audible when coasting in gear

I should have done this a long time ago but I pulled the timing chain tensioner today and found it's extended to 16.5mm.
I'm going to start a new thread on that since I want some advice one the best way forward. But I'm currently swinging towards the grinding noise being the timing chain catching the valve cover as the forces on the engine change during engine braking, accentuating the slack.
I have a few other possible culprits..

Either way there's no timing chain noise at start up, ticker over or when revving in neutral so it's not immediately terminal . .