I noticed an oil leak around the oil-filter housing (oil-cooler) and after some Googling/research, apparently this is quite common across Nissan and Infiniti models. Most refer to p/n 21304-JA11A, a square cross-section o-ring which sits in a groove in the cooler. When I check using my VIN at parts.infinitiusa.com, they only show a flat gasket which sits behind the oil filter bracket and the engine itself. No o-ring is shown in the parts diagram.

In a DIY thread here on the same topic, someone asked the same question but got no response.

Interesting - when I go back to that parts site (linked above), put in my year and model and in the search box put "oil cooler gasket", the 21304 parts comes right up. Mistake I made previously was drilling down through the links. I picked "engine", then "lubricating system". This part is under "Exhaust and cooling". Oil "cooling" .... duh !

Amazon was telling me that that p/n didn't fit my car and while I know it's not always 100% accurate, it made me wonder. I did see the part listed and a few of them were black o-rings. Some research I ran across indicated that orange is correct. Also, Dorman sells a replacement part for this and sells it as a 3-pack. Why would they sell it (3) at a time ?

Calling one of the local Nissan dealers in the morning. Apparently Nissan sells it for one price while Infiniti sells the exact same part for a higher price ! Go figure....

 

"Calling one of the local Nissan dealers in the morning. Apparently Nissan sells it for one price while Infiniti sells the exact same part for a higher price ! Go figure...."

Try looking up a complete stock type fuel pump assembly for an early G35 coupe then the same for a early 350Z - huge difference in price - same assembly.

 

$5.65 at Nissan, $8.43 at Infiniti. The lady at the Infiniti dealer said all of their parts are labeled "Nissan" so they don't even try....