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Discussion Starter · #1 ·
Man, I'm going to get a ton of flack for asking a really vague "what's wrong with my car" question, so please make the flames entertaining for all, OK? :p

2001 9-3 with 175k miles...

My car developed a subtle rattle from the engine between gear shifts under higher acceleration (merging onto the Interstate). I thought the noise might be valve float - sounded a bit like gravel or marbles rattling around in a can. The noise got progressively worse over a couple of weeks, until one night there was a drastic change in sound. The engine died after running rough for a few seconds (anywhere from 10 to 30), and I figured I might have dropped a valve.

If driving the car for two weeks like this wasn't stupid enough, I pulled the head without doing a compression check. I have (had?) a slight leak in the head gasket, so my original plan was to do a complete head rebuild with the gasket job. I pulled the head, and the valves are all intact. The cylinders have a bit of flaky deposit on them, but the more knowledgeable folks I've queried say that nothing looks unusual to them given the mileage on the vehicle. Still, no compression data...

So, the vague question: what might have been causing my car to run roughly like this? Does this seem like a DIC issue? Or maybe a fuel issue? Throttle body?
 

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Discussion Starter · #4 ·
Turbo: good thought. I'll give that a go.

lms: weird thing is that it died rather quietly the first time. The battery died after a couple attempts to turn it over. I got it jumped, drove about a mile, and it quietly conked out again. Not so lucky the third and fourth times it died (I'm trying to limp it home at this point). The engine at this point is rattling like crazy. I get to a slight hill, and lose all power. From that point on, it wasn't moving without the wrecker pulling it.
 

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Discussion Starter · #6 ·
Not sure I know what you mean by extension on the tensioner. I pulled the camshaft cover off first. The chain didn't appear to be loose at all.

Next I pulled the chain tensioner out to remove the cam sprockets.
 

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The chain will rarely appear loose between the cam gears, it's a very short distance compared to the rest of the distance the remainder of the chain covers.

When you pull the tensioner you are meant to remove the small bolt (with plunger and spring first) that way the tensioner's foot will remain in the same place when you remove it allowing you to measure the extension and get an idea of the timing gear wear.
 

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Discussion Starter · #9 ·
I didn't have a chance to mess with the car over the weekend, so I don't have any updates.

Regarding the tensioner, all I can report is that it didn't *seem* loose on either section of the chain that I could see. Removing the tensioner, I definitely felt some load being relieved, so there was some amount of tension on the chain.

I'm going to see about bringing the DIC to the Saab folks down the street from me (Scanwest in Seattle). They can probably test that (for a few $$) so I can strike that component off the list.
 

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Discussion Starter · #10 ·
Piston rod big end bearing cap missing!

It's been a few months since my original post, but long story short, I ended up buying a "new" 2002 Saab 9-3, and figured I'd use this problem car to tinker with (after 180k miles, this car needs a lot of TLC).

I pulled the engine, and just today started tearing down the internals. I discovered that the #3 cylinder piston rod big end bearing cap was completely gone! I'm pretty sure this is a contender for the culprit of the engine running poorly.

Questions: how would this part fail? I read in other car forums that lack of oil is a possibility? Are there others? What did I damage? Crankshaft? Piston? Head?

I'm still toying with the idea of a complete engine rebuild to get this car running again, but I'm admittedly on the fence.

Thanks for all the earlier suggestions, and for any new ideas.
 

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I would imagine it would be sludge that reduced oil flow/pressure meaning that the bearing was not properly lubricated (#3 and #4 suffer first since they are furthest from the oil pump). If the entire bearing was gone then I imagine both the crank and rod (w/ cap) are toast. The crank could maybe be machined and then oversized bearings used. Also I'd pay close attention to the cylinder wall at #3 since the extra play can allow the rings to wear the walls.

It's possible that the engine could be rebuilt, but I suspect it would make more economic sense to just put a used engine in or swap in a complete bottom end.

Also well most of that bearing material should have stayed in the pain, its possible that some circulated through the engine/turbo and did additional damage.
 
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