I have a 91 Z28 L98. Where the oil filler cap is on the valve cover, there always appears to be oil residue there even after i clean it. What i have noticed is that cap does not seam to seal air tight, so i think oil is getting past it. what i want to know is this normal or should i go out and buy a new cap?

Thanks,
Steve

 

My guess is that it is not normal, but the cause is probably a bad PCV valve. I would replace that first.

[This message has been edited by Mike89GTA (edited February 22, 2001).]

 

They are supposed to seal, but very often they leak after the Belleville washer that's supposed to keep them tight loses its "dome" attribute. As cheap as they are, like 4 bucks or something, if you don't like the leak, just get a new one.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Your cap is the screw in type with the anti-over-tighten feature like a gas cap right? It's too cold out for me to look but isn't there a rubber washer under there? Red or pink I think?

Shake the PCV. I don't think oil would make it through the threads even if there was no washer. I could run mine with it off and never get a drop to fly outta there. Some source of crankcase pressure pushing 'oil mist' through there IMO.