My friends 560 sec is running a little warmer then we
would like it to.We replaced the t-stat the spring was
broken inside ,refilled the radiator with a-freeze
roadtested it but still no good.It stays around 90-100c.
The radiator was replaced 2 yrs. ago.The viscus fan appear's
to be working properly.The aux. fan is also working ok.
If anyone outthere has seen this please give me a shout".


Thanks
P.A.R

Did you refill thru the top hose and run the heater at full tilt with cap off when, refilling with coolant while idling the car to normal temp? You may have air bubbles in the system..

...My friend just changed the water pump, stat and radiator on his '91 560SEC. He now has it running at around the 85 mark in town and on the highway. He had all sorts of trouble getting the water pump off as it looks as if the guy that changed it before did not take too much notice of the different bolt lengths. The bolt at the bottom of the pump was longer than it ought to have been and even with the front damper all but off, we still struggled for a while before we could wiggle the puppy off ! Looks as if the previous pump was installed before the front accessories were installed (possibly as an engine rebuild on a bench). Once it was all back together, he told me the way he got rid of all the bubbles was to position the car on his drive, front end high and continually top off the water/coolant mix until all the bubbles disappeared. Seemed to work for him anyhow ! Might be worth a try...

Too much anti-freeze?
 

Should have no more than 50/50 solution of water/antifreeze. If so, this will raise engine temp.

Check this link out for Water Wetter: http://www.redlineoil.com/frames/watrwet.htm