WBYonder

Just replaced the battery on my 2009 CS. Got a Super Start Platinum AGM from O'reillys. Glad I checked here in the archives on this subject. As was mentioned, everywhere I checked the parts catalogs showed that an H8 was the indicated size. I checked the battery that I had and it indeed was an H9. Don't know why everyone has it wrong, but they do. Replacement battery fits perfect and fired the P!g right up. Kept a charger hooked up when I made the swap and got no codes thrown or problems. Only small issue was the battery vent plug was inserted on the side I needed and I buggered it up trying to get it out, but eventually got it out, vent line in and plugged the other side. Overall, job was pretty easy and straightforward.

Petza914

You sure you got an AGM battery? I thought those (Optima being the most well known) were sealed and didn't require a vent line. Can't recall if the Napa H9 AGM I put into my 957 had a vent line or not, but I'm thinking not.

jhbrennan

Optima is not vented but AGMs from Bosch, Interstate, etc. do have vent outlets on either side.

Petza914

Good to know. Thanks.

WBYonder

Yes, specs on the new battery say that it's vented to the outside.

http://www.oreillyauto.com/site/c/de...0423&ppt=C0005