1991 190e leaks radiator fluid under fan

It is most likely to be your waterpump... that is the weep hole you are talking about...when the bearing or seal going bad... will leak through that hole.

Eventually it will get worse so it is probably time for you to do the waterpump, hoses, thermostat, clamps... etc.

Thanks. is this a job I can do myself...or not really?

Yes, you can do the job yourself... it ijust take time to do it...if you got the 2.3, it is not too bad of a job... take the fan off... then the radiator shroud so the fan will come out together... and you got a pretty good access to the whole thing.

The 2.6 take a bit more time and effort... you start with radiator out,then the rest because the space to get to the fan bolts are harder...

In any case, it would be best to have a service manual to guide you thtough the process.

ater pump is my guess. Depending on its position when it stops it will/wont leak

cheers