thermostat or waterpump issue ??
 

coolant fluid is gushing out from the radiator cap area when engine gets warm. Cap seems to be just fine, this happened all of a sudden AFTER I bought the car?? Any suggestions ? 91 500 sl with 93k miles...thermostat ? pump ? clutchfan? fan is ran off of belt and when shut off, fan will turn with no problem--bon't will not spin freely.. JUST had my powersteering pump replaced Friday and now this....

I don't know what your problem is but I will say one thing. Its always the thermostat. By that I mean that I would not consider fixing an overheated condition without replacing the thermostat. They are easily damaged by an overheat and are cheap so why take a chance. No matter what the problem was, replace the thermostat anyway.

You didn't mention the temperature gauge?

temp gauge slowly goes up, went up to about 215 or so according to gauge--gauge only goes to 220 then shows red after that....so I shut off car

The old wive's tale is that thermostats fail in the open position.

That has not been my experience.

Follow Steve's advice and replace the thermostat first.

I'll have someone swap thermostats first, I wen't to take the thermo housing off, 2 of the 3 bolts are Absolutely tough to get to, 1 bolt does not want to turn, so I'd rather let a mechanic do this job properly before I screw up and mess up the bolt head. I found the prices for water pumps.
Laso--$152.82
Hepu-$151.00
Graf--$124.90 free shipping on either brand

What would be a reliable brand

Just wanted to update: Found the problem to be the RESERVOIR TANK, surprisingly under the cap (where that meets the plastic tank--it cracked some, ordered a NEW tank for $79. thanks for all the help