2003-2011 [Subscribe to Daily Digest] |
Subject: Diagnosing Oil Leaks or Consumption Concerns
Models:
2003-2007 Saab 9-3 Sedan with B207
2004-2007 Saab 9-3 Convertible with B207
2006-2007 Saab 9-3 Sport Combi with B207
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
CONDITION/CONCERN:
A technician may comment on a difficult to reproduce oil leak or consumption concern on a B207 engine. The engine may leak oil only while driving under load, and this may be a repeat concern. A failing PCV system may cause oil leaks only while driving, when boost pressure escaping the cylinders from normal blow-by causes the crankcase to become pressurized. This will often cause oil to be pushed through the crankcase ventilation tube into the turbo, causing oil consumption and smoking. If this condition is encountered, the following diagnosis may help isolate the root cause of the oil leak or consumption.
RECOMMENDATION/INSTRUCTIONS:
1. Check for excessive oil in the compressor and turbine housings of the turbocharger. If oil is found only in the compressor side and intake tubes, this is likely due to a PCV system concern; proceed with the recommendations in this PI. If excessive amounts of oil are found in both the compressor and turbine housings, the concern is not likely to be related to a PCV system failure. See PIC3890A for further details.
2. Check cylinder compression. The minimum allowable per WIS is 180psi, and all cylinders should be within 10% of each other. Check cylinder leakage, all cylinders should be within 10% of each other. Correct any mechanical concerns found.
3. Remove the crankcase ventilation hose from the rocker cover; inspect the hose going to the turbo for restrictions. Start the engine and allow it to idle. A slight vacuum should be felt on the port at the rocker cover. If no vacuum (or positive pressure) is felt, swap the valve cover and retest. If there is still no change, remove the intake manifold and replace the PCV check valve/orifice assembly located between cylinders 2 and 3.
4. If a vacuum was noted at the port on the rocker cover and the engine leaks oil only while driving or under high load, replace the check valve in the intake manifold.
5. If all of the above checks are O.K. and the engine continues to leak oil at idle or while driving, repair the leaking component per normal WIS procedures.
6. Vehicles that exhibit an oil consumption concern and all of the above checks are O.K., replace the piston rings.
*************THIS INFO IS A LITTLE DATED YOU CAN NO LONGER PURCHASE THE PCV AND VALVE COVER SEPERATLY THE COME AS A KIT******************
posted by 209.195.165...
, Sat, 24 Nov 2012 19:42:19
, Sat, 24 Nov 2012 08:59:50, Tue, 27 Nov 2012 07:55:24
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