S Oil cooler bottom hole sizes are different to non-S ?
 

Four underside hole sizes of S oil cooler(996-107-025-59) look all same to me on photos searched at Pelican. But for those of non-S cooler(996-107-025-07), two inner holes are definitely larger than two outer ones, and the O-rings Nr 21 and 22 listed on Sunset and Atlanta are available in 3 different sizes; two 26x3, four 35x4 and two 18.77x1.78.

By JFP in PA ​http://986forum.com/forums/performance-technical-chat/61146-s-oil-cooler-non-s.html. S oil cooler(996-107-025-59) the latest version is switchable, I understood, to the base 2.5L Boxster, my 1999 Tiptronic, except only the very earliest 2.5L cars (1997 and early 1998) with intermediate piece.

Am I straying too far?
CK

upper ; Non-S oil cooler(996-107-025-07)
lower ; S oil cooler(996-107-025-59)
http://986forum.com/forums/uploads02...1498781997.jpg
http://986forum.com/forums/uploads02...1498782012.jpg

When I installed a 'S' oil cooler on my '99 it was a direct replacement. The holes should not be in different places. I used a Behr (OEM supplier), Behr PN: 376726111, Porsche PN: 996.107.025.57. Note that the last two digits of the Porsche PN are the version number, a have no affect on fitment.

Thanks..
So, whether the two hole sizes may be different or not, but those are destined to align in each hole center axis without leak issue?
Do you possibly remember what sizes of the new O-rings used?, four larger seal rings for the taller S type cooler?

cf; Different hole sizes of the upper surface of the engine block in reference photo 29 of projects 11; Pelican 101 Projects


CK

Photo added
 

The holes in the engine case are different sizes and require different O-rings. The openings in the oil cooler are slightly different, but still function perfectly.

Stop over thinking this and slap the puppy in there, being sure to correctly torque it. Your engine will thank you. :)

I'm about to do this little upgrade myself. Allow me a dumb question: do you need to do a complete coolant flush and bleed with this swapout?

By the way, what the heck would we do without JFP on this forum? Seriously.:cheers:

No, but you do need to lower the coolant level as the cooler is the highest point in the cooling system. If the coolant mix is four years old or older, just dump the system and refill it with fresh.

Even with the cooling system level lowered, you need to lift the old cooler very slightly without tilting it, and slide a plastic bag under it before pulling the rest of the way out. The four holes below the cooler are two for oil (in and out) and the same for coolant. As there will always be some oil and coolant retained in the old cooler, if you tilt it without covering the bottom, you risk getting oil into the cooling system as well as coolant into the oil system passages. None of that is good, so get a large plastic bag to slide under and up the sides of the old cooler before removing it. ;)

WOW...
Need_for_speed; Cool question!
and vivid practical points drawn.
Risk of mixing oil with coolant! Scary to stand my hairs on end.

While ago I glanced at the Bentley's, removal and installation procedure of oil cooler, to direct draining at the coolant manifold drain plug underside of the engine case . I have to go through it.

My humble respect to JFP again.
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CK