Viscous fan clutch failing on '89 300E?
Experienced an overheating problem on my '89 300E with 151K miles this past weekend which I believe a new thermostat has solved. However, the fan clutch just spins when I turn off the engine when hot and doesn't seem to spin above a certain RPM when revving the engine while stopped.
I thought the viscous fan clutches locked into place after the engine temp. reached a certain point. Shouldn't a fan clutch on a hot engine keep up with engine speed? Is there any way to determine if I am subject to failure soon? Don't want to overheat again.
Thanks for any input. I have a new viscous fan but will return it to the dealer for a refund if my existing one does not appear to be failing.