Cylinder block base o-rings

Hey guys,

I'm about to install the cylinder block on crank case. According to partzilla cylinder block diagram it shows o-rings of 67mm and 67.5 mm on the underside of cyl. bl . I do have a set of red o-rings that came with my complete gasket set. The thing is that I can't find anywhere in the service manual any mention of these o-rings. Also I kind of find it a bit odd to install o-ring in that location.

I would appreciate any pointers on that issue.

Thanks
Keep on sixing!

Those O-rings seal the cylinder sleeve (steel) to the cylinder block (aluminium)
If you have not pulled the sleeves there in normally no need for them.

Thanks for the quick response. It makes a lot of sense, now.