Need to get my car on the road today. Anybody able to explain the 1/2 inch diameter O-Ring that goes in the block under the rear main bearing cap?? The only hole I see is the hole for the oil pump shaft. It appears to be 1/2 inch in diameter but I don't see a way the O-Ring would be held in place. I need to mention this is a 3.1L to 3.4L swap. So, the block is a 95 3.4L block. Did they change things so it is not used in the 3.4L?? Nothing in the 3.4L swap notes about this... The rear main seal is packaged with instructions that say it is required for GM V6 engines.

Do I just push down into the hold where the oil pump shaft goes?? Help???

Picture?

There's no O-ring needed on a 660 that I'm aware of.

There might have been a V6 (not a 660 though) that used an O-ring to seal the oil pump...

Great, thanks.. Just found a thread on the Camaro Forum about it.. The guy there said he called the Chev dealer and they said that some have it some don't.. Almost sounded like they tried it on early 93's but found it a waste of time.. No matter how I look at it, there is just no way to install an O-Ring under the bearing cap.. So, unfortunately, I had pulled the pan back off and the bearing cap only now to find it isn't needed.. Bearing cap is back on, pan is back on, new rear main seal is in, and now on to the clutch, bell housing, and transmission... Then, into the car to see if this 3.1 to 3.4 will actually work.. It's a 92 RS by the way...