There is a test spec'd in the GM manual for testing the optispark vent system for leaks. With the air inlet hose (the line that connects to the intake tract) plugged, 10" vacuum at the line to the intake manifold should hold (basically, the opti casing should hold a vacuum). The one installed in my car does not. The brand new one from GM I have at home does not either. It pulls air in from the electrical connector. If I plug that leak, it leaks from somewhere else.....the bearing in the back, I believe.

Has anyone done this test on their new optis? Do I have a "bad" new opti or is this a standard "feature"?

Thanks,
Rob
95Z28

 

Mine is not all that old, but is not air tight either. I am having no problems, though.