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Oil leak, white smoke, random misfires

2K views 9 replies 6 participants last post by  Doctor Who 
#1 ·
Hello everyone. I'm new to the forum and I've tried to search for this relating issue without any success, so i'm sorry if this is repetitive.

I have a 2005 9-3 Aero Convertible (aprox. 96,000 miles), and I noticed about a week ago that it has an oil leak (which has likely been there for months). White smoke comes out from behind the engine only while in idle (NEVER while driving).

I've started to get pretty heavy misfires too, I scanned the ECM and found that cylinder 1 and 3 seems to be the worst, and I have error code P0300 (Random/multiple Cylinder misfire detected), but the MIL is off. The misfires occur when accelerating hard, or when the engine is in idle and cold. Other than that, it starts up just fine without struggling.

With my OBD II scanner I've also found that O2 sensor 1 fluctuates a LOT (from 0.05-0.75V) while driving, whereas O2 sensor 2 seems to be pretty stable at around 0.65V. I'm not sure if that's relating to my issue, just figured that any detail will help.

The ignition coils are about 15 months old, and the spark plugs were changed almost a year and a half ago, which back then solved my misfiring issue.

Does anyone have any clue what the issue may be? I fear a leaking head gasket, but would like to hear anyone else's opinion before taking it to the mechanic... Except for the periodic misfires the engine really runs amazing for its age, so i'd hate to see the car go to waste. Thank you for any help at all!
 
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#2 ·
Smoke could be from a leaking coolant overflow tank, water pump or leaking thermostat if you're thinking coolant. Oil leaks in that area are most commonly valve cover or vacuum pump.

As far as the misfire, you probably have a vacuum leak somewhere. Also, what ignition coils did you use? Factory Saab or some from a parts store? If it's not the embossed coils, then it is more than likely failing coils as these cars HATE aftermarket coils.

Overall, nothing you described makes me concerned of a head gasket.

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#4 ·
Smoke could be from a leaking coolant overflow tank, water pump or leaking thermostat if you're thinking coolant. Oil leaks in that area are most commonly valve cover or vacuum pump.

As far as the misfire, you probably have a vacuum leak somewhere. Also, what ignition coils did you use? Factory Saab or some from a parts store? If it's not the embossed coils, then it is more than likely failing coils as these cars HATE aftermarket coils.

Overall, nothing you described makes me concerned of a head gasket.

Thank you for your reply. Regarding the coolant: I did have a leak half a year ago, but the leak was sealed and hoses were switched out along with the thermostat I believe (although the warning message of low coolant still pops up in the car). I had an oil done change last week and the mechanic confirmed that there is an oil leak, although he couldn't tell where it was coming from.

Regarding the ignition coils: I went with the budget variant from professional saab parts Sweden that I got off from eEuroparts. Could these be an issue?
 
#3 ·
Where is the oil leaking from? Vacuum pump? Valve cover? Pull the coils and plugs and see if oil is getting down into your plug area. If so, valve cover needs new gasket.

Check all your vacuum lines for leaks, cracked check valve, etc.... The T by the oil dipstick and the check valve that runs by the oil filter are notorious bad spots.
 
#8 ·
For future reference, you O2 sensor 1 should always fluctuate a lot and O2 sensor 2 should be stable when graphed over time. Obviously, when you accelerate or let off the pedal, 02 sensor 2 will fluctuate, but if O2 sensor 2 stops being stable when graphed over time, something is going on.
 
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