Expansion Tank from '99 2.5L to fit on '97 2.8L?

[jmdarius]

Hello friends!

I am in the midst of the viscous mechanical fan delete (to avoid possible explosion of brittle plastic fan blades, and to reduce some parasitic power losses). However, the '97 2.8 has the coolant expansion tank mounted to the mechanical fan shroud, attached to the radiator. With the mechanical fan now gone, I'd love to buy back more space to work on the front side of the engine by not having to put the empty shroud back in. I noticed that the 2.5L Z3 mounts the expansion tank behind the left strut tower. Is it possible to simply mount that same expansion tank into the 2.8 with the proper plumbing and hoses? Or does the 2.8 not have the same mounting points?

Further side note - in the mechanical fan delete I also did a full coolant system overhaul to replace old plastic bits (water pump, thermostat, thermostat housing, upper and lower radiator hoses, accessory belts) but kept the same factory radiator. Would you say it is necessary to replace the oem radiator as well? Almost 60k miles on the car now.

[zellamay]

I did it. The earlier Z3 doesn't have the mounting brackets, so I got 2 "L" brackets, with holes in them, from the hardware store and screwed them into the shock tower. I had to bend one because it was not a 90 deg position. The new tank had 2 hose connections on the bottom, so I capped one. I just used rubber hose, rather than that expensive BMW hose setup. Been working fine for a couple of years. It is so nice not to have the tank hanging around up front.

[Corellian Corve]

So the later expansion tank has two hoses underneath the tank, in addition to the top overflow hose. Besides brackets, you'd have to adapt the hose that goes to from the bottom of the original tank (older style with clamp) to the newer style with locking ring. Then you'd have to cap off one of the connections.

These parts are under pressure, too. So while it sounds like zellamay made it work, there is no hose barb on those connectors (and they are facing down) so I would be nervous about how well hoses would hold up to that with just a clamp.

Although sounds like it would work, it also seems like a lot of effort and expense with some risk.