My 1987 260e threw me the coolant light the other day when I was driving. I hurried home and popped the hood to see where the anti-freeze went. It appears to be the water pump because i can see the area surrounding the water pump is wet with the blue fluid. So anyway I haven't got around to get it fixed but still need to occassionally drive the benz. I called the dealer and they said no we don't have blue fluids, the antifreeze has been superseded by the yellowish fluid (as per Mercedes-Benz). So I ask can I mixed it in with my 260e blue fluids because I only need to top it up for awhile. He says yes no problem I can just go and mix the two, but get and get the pump fixed asap.

Should I believe the guy that I can mixed their Yellowish anti-freeze with the blue stuffs that's in my benz? Or is he just trying to ensure I come by for a big big engine job in a few months time???

PS: HOw do I diagnose that it is infact the pump?