Editing S130/coolingfan php (section)

=== Diagnosis ===

Symptoms can vary widely. If the clutch has lost fluid it may slip excessively. It may allow overheating at low RPMs but allow adequate cooling at highway speeds. It may do just the opposite, or allow overheating under any driving condition. Parts inside may come into contact and lock the fan after heating up, causing it to overspin and generate excess noise.

Some things to check are as follows:

* Look for oil on the outside of the clutch body.
* Grab the fan (with the engine off!) and move it side to side while checking for excessive play.
* Rotate the fan by hand. It should turn freely. Try to give it a good spin — if it rotates more than half a turn, it may have lost fluid.

If you have an overheat problem that defies diagnosis, it may be the thermostatic clutch. Something else to consider: The clutch is “stack mounted” on the water pump. If the clutch is bad and out of balance, it can — and often will — cause failure of the water pump bearings. Considering the clutch is often between $30 and $60, and you have a mysterious overheat problem, it is worth the price to replace.

![Checking a clutch fan](images/Clutchfan/Checkclutch.gif)