Firstly, good luck with your trip.

May I advise that you check the fluids in your shocks if you haven't already? 40k on a bike usually means a lot of abuse (in the right sense) so the shocks might want checking. Spring a leak in one of those and your handling goes to poop.

As for the extra cooling, it's a personal choice, but not one that seems necessary unless you're already having overheating issues. From personal experience an air-cooled engine at full chat through scorching desert managed to survive without any damage; a bike with more advanced cooling methods should not have a problem. But, as always with this kind of thing, go with your gut - if you feel you need it they you probably will.

Also it might be worth taking the bike to a bicycle shop (assuming you're in China) to have the wheels trued and the spokes tightened. Those are often over-looked during regular maintenance.

Aside from the obvious mechanicals may I advise you take photocopies of your documents? It is the case that some foreign authorities will take and withhold the real documents to extort bribes or deny the return of them for other nefarious reasons. If you are requested to provide documents handing over a photocopy for close inspection while holding onto the real article could save from some awkward situations.

May I inquire as to which route you plan to take to Europe? Russia (Via Mongolia & Kazakhstan into Europe) require specialist documents and the Middle East has its own well known problems. I ask from the position of somebody who would some day like to attempt this same journey.

Again, good luck.