You said you pressure tested it. I assume you meant pressure testing the cooling system. Did the gauge hold pressure? Just because a head gasket leaks doesn't mean it leaks into the combustion chamber. It could only be a blown gasket between the coolant jacket and oil jacket.
I don't see that bulletin, do you have a copy of it or a link?
On this engine, I see a coolant hose connected to the throttle body, make sure that the coolant isn't entering the engine at that.
Hi, If the coolant was entering via the throttle body it would enter the cylinders and burn off giving smoke and cleaning the plugs and piston tops, this should also give a hard start, misfire or poor running condition, which is not evident, but. I have already peeked in the throttle body and no signs of staining or coolant when pressure tested. I don't see how the coolant would enter the oil pan this way unless its bypass from washing down the cylinders giving above conditions. I should mention the oil has about 2 liters of coolant in it since I changed it a week and half ago, this amount would definitely show out the tail pipe. The only way I see it entering directly into the oil pan is either a head gasket ( with out the usual signs in the chambers ) or a cracked head/block, are either of these a common issue with this engine? or am I missing another option, like the tsb I found, but it was only listed on the internet sites with a release date of early 2007.
I didn't find anything listed under tsb's for any cracks or even coolant in oil. I did find what you were talking about though,
2005 Chevrolet Aveo 1.6L MFI DOHC 4cyl vin 6.
L91 2003 to 2009 ENGINE,1.6L,MFI,DOHC 1.6-6(L91)
That is the correct RPO, L91 is the 1.6L MFI engine.
Give me a few minutes and let me see if I can find out how to replace that casting plug.
I cannot find anything on repair, only links to the tsb that say RESEAL CASTING PLUG. I don't have anything in my Chilton online and can only find the same tsb at the gov site.
Results : 1 | All records displayed Make / Models : Model/Build Years : CHEVROLET / AVEO 2004-2008Manufacturer : GENERAL MOTORS CORP. Service Bulletin Number : 4294 Date of Bulletin : DEC 01, 2007 NHTSA Item Number : 10023757 Component : ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:CRANKCASE (PCV)