Hard Starting Cold With Engine Misfire and Low Compression 2007-2008 9-3 B207

Burnside can you post photos of the offending valves when you get a chance.
I find it interesting that there would be a build up on the intake valves.... (Any build up should be on the exhaust valves as they are the valves the exhaust passes through. It's just air and fuel coming it the intake valves....)
Perhaps the valves are breaking down from... heat, friction, some type of chemical reaction form the fuel. burnt fuel....

Please correct me if I'm wrong. Isn't a valve made so it can spin (turn around slowly)? I think they are designed so they don't stay in the same spot all the time. If so they should wear pretty equally around the face. Wouldn't that keep any carbon off?

I have never come across a 9-3 with ring damage yet. I would take it to the shop to said they'd do it for $1500.... that's VERY cheap. $3500 is a little on the high side of things.
In my own car I have performed 2 GM top engine cleaner flushes through the intake with the car @ 2000RPM - (I use old plugs when I run these) - and ran the shit out of it the next morning to clear it out then replaced the oil and the plugs. This made a little improvement. Then I used some BG Induction Cleaner (same method) and it actually made it about 90% better. Now that it's winter it has the rough cold start crap and it idles like shit all the time. I've even tried bumping the idle 20rpm - no change. I will be fixing it come spring.

Pictures are from a 2008 9-3 2.0T I believe it had around 80K on it when I did all this. This car was repaired under the GM Powertrain Warranty.

Attachment 14170

Attachment 14171

Attachment 14172

Burnsside42,

As this is a known issue will GM do the work even if the car is not exhibiting symptoms yet? I know it is a long shot but I think a number of owners are very concerned about this issue and want it taken care of while the car is still under warranty (my 2008 still is but is OK so far at 56K miles). How many cars have really been affected so far out of all produced in the affected range? 1%, 10%, 50%? Perhaps you being in the "trenches" have a better feel for quantity of this issue. Has there been any discussion (official or otherwise) about the root cause of this problem? Bad batch of valves? Different suppliers? Ambient temperatures? It just seems so strange that it does not seem to be prevalent in early year production of the 2.0 engines that something must have changed and if so what?

Thanks for all the info so far it has been a great help.

Quote:

---

Originally Posted by Burnsside42

http://saabworld.net/images/imported/2014/01/14.jpg

---

Would you say the amount of carbon build up on the head and valves (above) is excessive?
I don't think my 2.3 with 363000km looked that carboned up. (See picture below... It didn't...?)
I would guess that there is a big difference in the cooling of the head vs the block on these 2L 9-3.
Does the 2L have an aluminium block?
I would almost bet the head on the 2L is cooler running than the 2.3L.

Yes, the block on the 2.0L engines from 2003 on, is aluminum. Remember that the photos of the 2.0L engine above has defective (failing, failed etc) intake valves.

Quote:

---

Originally Posted by AVguy

Yes, the block on the 2.0L engines from 2003 on, is aluminum. Remember that the photos of the 2.0L engine above has defective (failing, failed etc) intake valves.

---

I wonder what made them fail? (Carbon build up.) What made the carbon build up so much? I bet the head runs eather much hotter or much cooler than the block and pistons. I would guess cooler.
I can't remember the exact # but when I replaced the head gasket and lapped the valves on my 2.3 I'm sure the compression went up at least 20+ lb/ cylinder.
The valve seats looked good before I lapped them.
Could just lapping fix the 2L problems? (I'm sure the valves are the same in the 2.3 and 2L. around those years) The intake ones I replaced looked like the ones in burnssides picture.
With new rings and everything I'm getting 185lb average on a dry test. (It's slower turning over now. Especially in the cold!)

Quote:

---

Originally Posted by Finding41

I wonder what made them fail? (Carbon build up.) What made the carbon build up so much? I bet the head runs eather much hotter or much cooler than the block and pistons. I would guess cooler.
I can't remember the exact # but when I replaced the head gasket and lapped the valves on my 2.3 I'm sure the compression went up at least 20+ lb/ cylinder.
The valve seats looked good before I lapped them.
Could just lapping fix the 2L problems? (I'm sure the valves are the same in the 2.3 and 2L. around those years) The intake ones I replaced looked like the ones in burnssides picture.
With new rings and everything I'm getting 185lb average on a dry test. (It's slower turning over now. Especially in the cold!)

---

The 2.0L engine in the 2003+ 9-3 is a GM Ecotec engine with no commonality in parts to any previous Saab engines. The theory that seems to be the most accepted but never officially is the the valves in some (not sure of the percentage) later model 2007+ 9-3's (maybe 2006) with the 2.0 are not hardened properly and wind up getting a razor shop edge that can't hold compression.

Razor sharp edge. Well I'd guess they weren't hardened.
Just a note about the look of the valves in Burnsside's head picture and my head picture.
The intake valves are different looking. When I replaced my intake valves the replacements valves looked like Burnsside's! The shape of the head indentation anyway. You can see the heat treatment area on the head of the new valve. (I thought it kind of odd to only treat the edge... I thought the whole head would have been treated. )
I hope mine last... They probably will out last the car actually.
New on the left of each picture.

Burnsside42,

Any chance you have access to any of the failed valves? Someone over at that other saab forum has access to metallurgical testing equipment and they would be interested and willing to perform some hardness testing on a bunch of valves (new and used) to try and detect the actual issue with the failed valves. Just wondering...

Quote:

---

Originally Posted by AVguy

Burnsside42,

Any chance you have access to any of the failed valves? Someone over at that other saab forum has access to metallurgical testing equipment and they would be interested and willing to perform some hardness testing on a bunch of valves (new and used) to try and detect the actual issue with the failed valves. Just wondering...

---

I must say as a SAAB owner I too like my toys. (Tools/ Sailboats)
I'm not sure if the other car forums talk about stuff like this.
I love my SAAB's even more now!