I checked and it seems that the oil cap from an LS1 is the same as ours. I checked at kragen and again they were the same part. So I order a nice one from for an ls1 ls6 with the carbon fiber top that says mobil 1 5w30 on it and it goes on but does not lock, you can just pull it right off. I've seen people on here with the same type of cap I bought and am wondering if you all have the samr issue and if so do you use it anyway and does it stay on?
Heres the one I got
http://cgi.ebay.com/ebaymotors/ws/eB...146550555&rd=1

Any Ideas? I have not removed the air box or oil fillere tube yet but that should not effect it. I'll try it tomorrow and see what happens.

 

I think those type of caps are designed to be installed directly on the motor and not on the oil fill tube.

 

I have read that the stock cap fits the tube and if the tube is removed it fits right on the engine also. So wouldn't the same be for this aftermarket cap? I'll be getting an K&n or cgs sooner or later so it will be usefull someday, but I'd like to use it now.

 

Yes, the cap fits the same on the valve cover as on the fill tube. Ask anyone who has a CGS or other intake and has removed the fill tube.

The caps you've seen were sold by SoCal HHRs and I seem to remember him saying that they had been machined to work on the HHR. I got one and it locks on just like the oem did.

 

Maybe I missed something, but can you compare the two caps side by side to see what's different?

 

they look almost identical, My wife has Fiji at school right now so I can't take a pic, but will try to remember to do it this evening.