Costco here uses fitment code 6 for group 65 batteries.

 

I switched over to Walmart batteries when we were on the road once and couldn't find a Costco, They have served me well and Walmart's are purty much everywhere.

 

How strange! They've changed group numbers for that battery!

I could provide that exact same shot from under my hood and it would show a Group 4. Just ask and I'll go snap a shot of mine.

Weird!

However, I see that behind your loose tape on the split loom that you have a sticker from 2013. Mine are from 2010.

Pop

 

I just put Costco Kirkland in mine last month. So far, so good.

 

Just replaced the 1/06 Kirkland batteries in my 95 7.3 yesterday. The amazing thing is when I bought the truck, it had been sitting for 1 1/2 years with both batteries showing less than 1v. I charged them up and still managed to get over 4 years out of them.

 

It could be a US/Canada thing as well. That was my Christmas present this year a truck I could start.

 

My local Costco only has Interstate branded batteries, and don't carry the battery for the diesel. I bought one for the wife's Camry, and mom's Miata, but I'll guess I'll have to go to Auto Zone to get the replacement for my truck. Brandon is too far for me to drive for saving $15 a battery, and having to go all the way over there to get replacements if the need arises. I'd really like to get regular 65N batteries from Walmart, but the ones here only carry the 65S. Plus, I don't the the Deka warranty will cover a purchase from Walmart as they want the battery shop to "test" the batteries prior to paying out the remaining pro rate on the batteries.

Side note, the truck not starting was my birthday present right after birthday dinner.

FYI, you say the battery is a size 6, but directly next to it in a small box it says "65" still...

 

Funny this thread would have been revived by a link in another thread just yesterday.

The Costco batteries that started this thread four years ago began losing some of their reserve capacity, and since a cross-country trip was less than a month away, I decided to get new ones, again at Costco.

As I lifted the first one onto the counter in their tire shop as the "core", the gal said, "You've only had them four years. There's still some warranty remaining, and it MUST be more than the core charge will get you."

So I took them in to customer service, and they gave me $52 back for EACH one!

That went a LONG way toward paying for the two new ones!

This time, although they are in the same case (and again I guesstimate identical lead weight), they are now labeled "Interstate" instead of Kirkland.

They are obviously still made by Johnson Controls, but Costco probably sells more of them now.

All marketing, same battery.

Pop

 

I've said it before, they are made in the same factory. But if they are changing the brand to Interstate, they'll definitely have a winner.

I'd recommend Kirkland batteries anyway, from seeing their performance first hand, and I'd also recommend Interstate as well, again seeing their performance first hand.

That being said, I ran an original Motorcraft battery in my Ranger for almost 10 years. Why I didn't get a Kirkland was because the company I worked for sold Interstate batteries and I got a killer deal on it, cheaper than Kirkland.