I recently got a PO456 code (Evaporative System Leak) code with the engine light lit. I first checked the gas cap and sure enough, the rubber seal was full of small cracks. Since I was ordering some other service parts, I added a new gas cap to the list. But, being an engineer, I began to wonder if something else could replace the not-sold-separately rubber seal. Turns out a Dash 326 O-ring is a perfect fit! I have a kit of O-rings and after removing the old seal I fitted the new O-ring. I was concerned a little since the OEM seal/O-ring has a slot in it allowing a bit more flex and my new O-ring was not slotted. However, just after a few minutes running time, my engine light went off and all is well again! Simple, cheap fix: just wish I had tried this first before ordering that new cap.

Dash 326 O-ring should be available at lots of places and will likely cost very little, certainly less than a complete gas cap. Lesson learned the hard way!

Eric

 

Did your check gas cap light come on as well? or just the check engine light?

 

Only the Check Engine light came on with the code PO456 (I think). I have a spare, new gas cap now but am interested to see how long my cheap O-ring fix works. So far, so good.

Eric

 

This 6-year-old thread really came in handy for me. Recently I got a Check Engine Light. The issue according to the code was a leaky gas cap seal. I took your advice, went to Ace Hardware and purchased the O-Ring for only 69 cents! Swapped out the cracked seal with the generic O-Ring in about a minute and the problem was solved... no more Check Engine Light.

The size O-Ring that worked for my R53 Mini: 1 5/8" inside diameter x 2" outside diameter.

Thanks, Eric for this simple and inexpensive tip.

PJJ

 

I'm very happy to hear that my inexpensive solution to the gas cap seal problem has helped out another Mini owner. Good for you doing a search and finding this old thread.

Eric

 

Another thank you over here...

Pretty sure the car passed state emissions inspections this afternoon because of this thread! Was consistently throwing p0456 that I'm assuming was triggering other fault codes. Changed out and completed drive cycle. Car passed with 4/6 monitors "ready".