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'96 Aero sounds like a diesel

2K views 18 replies 12 participants last post by  rawill 
#1 · (Edited)
Hi all

Was driving my 96 Aero AUTO last night on a 200 mile round trip. Got about 60 miles in and noticed that my car sounded like an old diesel tractor! I immediately pulled over, checked the oil - half way between min and max, checked for oil leaks etc and found none. The temp gauge was reading half way between cold and the halfway mark. Started it back up again still sounded like a diesel. Perhaps it was stupid but I drove it about 200 yards down the road to a layby, I knew I was going home on a truck and thought I'd park it somewhere safer than where I was.

When I was driving I noticed a loud rattling/banging noise so I kept the revs down below 2000 and it wasn't so bad. The worrying thing is that I was blasting the stereo for the entire journey (until I noticed it wasn't going properly) so I'm not sure when it started playing up.........

The AA man wasn't an AA man but an agent, he seemed to think that it wasn't anything too serious as it idles OK. It does sound a little tappety at idle where as before it purred with no tappet noise at all, even when cold and after not running for a few days. He reckoned the banging/rattling was something loose in the engine bay but couldn't work out where. He also suggested that it may be a blocked injector but he wasn't sure.

The car doesn't appear to have lost any power as it happily drove up the back of the transporter (one of those ones with the flat bed that slides off the back) that was easily at 45 degrees.

After reading a few posts on here I decided to change the DI thing and this hasn't really made any difference.

Another thing I noticed was the check engine light flashing a code at me. One long and 6 short flashes which I believe is a faulty lambda probe. Could this be related to my problem?

I also put about 20l of Super unleaded in about an hour earlier.

Does anyone think they know what might be wrong?

Many thanks in advance
Conrad
 
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#4 ·
Thanks for the replies. Sadly I thinks it's much worse than I originally thought.

I had a Saab tech call round earlier and he reckons it's the big end bearings that have gone. He had the top of the engine off and said the timing chain was fine. He was about 90% sure he was right.

Would you all agree that these symptoms are indeed signs of big end bearing trouble? Doesn't sound quite as much like a diesel now (I replaced the DI thing) but it is a bit tappety and when the revs go over 1500rpm there is a loud metallic hammering sound that increases in speed as the engine does.

Is this a huge job? I really don't want to scrap this car as I've only had it a few months and I really love it. What sort of money would a back street mechanic charge for this sorta job, would it be more than the car is worth? The Saab guy didn't seem that interested in taking it on so I'm a little worried now......

thanks again
Conrad
 
#7 ·
First thing to do is drain the oil into a clear container, ideally a fridge veg container. Leave to settle then decant oil out, then shine torch underneath to highlight any metal particles. Lots of shiny silver or copper bits shows the bearings have failed or are their way out...usually its no. 2 big end..don't ask me why no.2 but I've stripped a few wrecked engines and no. 2 big end usually is in worse condition.
 
#8 ·
it will idle fine - not sound bad - knocking increases as you load it = :cry: exactly what a failing big end will do - the more you run it - it will quickly turn into a piece of scrap - if your lucky - the shells are not completly gone = simple and cheap drop sump - fit new shells and off you go

but could easy be crank journal is goosed = complete engine strip - re grind etc.. way above the value of the car
so it,s flip a coin time - me i,d go straight to KevinC recommedation if you paying for the work
 
#9 ·
Robinb said:
Does your car have high mileage and/or a history of abuse? Those engines are quite robust.

I have never heard of a Saab 9000 turbo owner reporting big-end bearing failure after everyday use, although I'm sure it must be possible.

Its got 170k and a full service history.

I just can't understand why this happened so suddenly. No warning signs, no nothing. Anyone I've spoken to whose car has had the big end go said they knew it was going ages before it actually went.

Is it common for the big end to just go like it has? Wouldn't I have heard something over the days leading up to the failure? Before the failure the engine purred, it really did. Not a peep from the tappets or a rattle from anything else for that matter. Honestly, it sounded like a new car.

I've driven 9000's for about 14 years now and in that time I've owned 3 (2 that have actually been on the road the 3rd is a 92 carlsson with TCS problems but thats a whole other story). I completely abused these cars and they never once let me down with engine problems. My last one (9000 2.0 CS) lasted 7 years, was serviced twice and went like a champion despite the abuse I gave it.

I'm not sure this is relevant but I put half a tank of supermarket Super Unleaded in at the start of the journey.

I do remember overtaking someone on the motorway and the auto box didn't change from 3rd to 4th before the revs hit the limiter. I heard this happen and let off the power a bit and it engaged fourth and off I went. I don't think this would have done it as I've hit the limiter loads of times before on my other Saabs with no problems.

I'm going to drain the oil and look for bits of metal etc.

My head is fried :cry:......
 
#10 ·
Norman Lovie said:
it will idle fine - not sound bad - knocking increases as you load it = :cry: exactly what a failing big end will do - the more you run it - it will quickly turn into a piece of scrap - if your lucky - the shells are not completly gone = simple and cheap drop sump - fit new shells and off you go

but could easy be crank journal is goosed = complete engine strip - re grind etc.. way above the value of the car
so it,s flip a coin time - me i,d go straight to KevinC recommedation if you paying for the work
That's exactly how it sounds. Thanks for the bad news Norman.......

My Saab man said exactly the same thing about the shells. Thing is that because the lovely Aero stereo was blasting very loudly I'm not sure how long I was running the car like this. I think I noticed it pretty quickly though.

Thing I don't want to risk is replacing some bits and finding out loads of other bits are shot too. Is there a way to tell how badly the engine has been damaged with out stripping the whole thing? Would whoever is doing the shells be able to tell if other bits are needing replaced while he is down there?

I think I may well just try to source a good 2nd hand unit somewhere and get it fitted. Would hate to splash a few hundred or more on shells and fitting only to find I need to spend another wallet full on the other bits too. Perhaps the new engine idea is the best?

I'm away out to search the streets for a lucky penny :roll: I hate my life......
 
#13 ·
Many many moons ago I had the big ends go on a Mk2 Cortina :D that I had just recently bought. Money was tight and I really couldn't afford to pay for a mechanic. A mate who knew more about cars than I did then helped me out by supervising me replacing the shells. I did it by the side of the road in 3 hours. Dropped the sump unbolted the big ends replaced the shells torqued the bolts replaced the sump gasket and reattached the sump. Easy. And a lot cheaper than paying a mechanic and a mere fraction of the cost of replacing the engine even from a breaker's yard. Go for it. BTW I had to return the favour by helping him replace the rear subframe of a mini. Now that is not something you want to do too often
 
#16 ·
Your post has brought back unpleasant memories I`m afraid - bought a beautiful Griffin wirh 120k on it, full history, drove tight & very well. 300 miles later on a routine drive home used one bit of boost in an overtake. 10 miles later thought I could hear a tap tap tap .........Radio off, slow down , sound goes, gently up to 50 it`s back. Almost instantly huge increase in noise, as I pull in at home it`s gone completely & sounds worse than any tractor. Trailered to my trusted garage, pronounced dead - crank damaged, rods damaged, if I`d been very very lucky then might have stopped in a 1/2 mile & got away with it, but apparently the shells often creep round & do a lot of damage.
So, had my OLD engine with 220k fitted, and it`s running as well as it did in my old car, but it really has been treated well for 120k by me.
`Full service` must have involved a lot of crappy quality oil changes maybe once a year. The pickup is low down & sucks up consequent sludge, rapidly blocks all flow. By the time the light`s on it`s all over. Should have had a sump drop as soon as I bought it.
I do hope yours is a happier ending.
 
#17 ·
We've dealt with a couple of Saabs with broken exhaust studs in the last several months........... maybe the noise is that? Have a good look at the exhaust manifold and make sure all the studs are there and that the flange is tight to the head...
 
#18 ·
Very common for the exhaust manifold studs to break off at the gasket. Also, sometimes the turbo to manifold bolts break. The symptom is a tick or spitting sound due to compression wave leaking. I actually diagnosed mine with a cheap CO detector (put down by the exhaust manifold with the engine idling) as the exhaust upstream of the cat is loaded with CO, downstream of the cat there's not enough CO to set off a detector!
 
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