Ricambio are good in that they have a good stock of parts and ship them out quick. 126 fan are a fraction of the price , the parts are good , they just take a little longer

If your cooling fan was loose then I would say that you have certainly overheated the engine and it sounds like the push rod tube seals are shot.
Have you now got the complete proper mount for the fan ?
To perform properly the fan has to turn 50% faster than the engine so at high revs it gets over 8,500rpm.
The standard fan on my modified 500 engine let go at about 6,500 revs on the engine then the engine massively overheated when I tried to drive the 4 miles home. I did not make it as the engine died about 300 yards from home. When it cooled down it would not start due to lack of compression. Most of the cylinder head nuts were finger tight so I guess that the studs had stretched. I removed the head to check it out, all looked fine so put it back together and it ran fine for a while until I discovered that the studs holding the rocker shaft to the head had stripped. Fixed that and it has been fine ever since.