Chrysler Repair: Water Pump, losing coolant, coolant level

Question
Is there any way that you can detect that the water pump is going bad. The temp needle on my car fluctuates between H and C. Sometimes get really close to the H. Can you help please. Any suggestions would be appreciated and looked into.
Thanks.

Answer
Hi Michelle,
It is possible for the impeller to be slipping on the shaft of the pump, but not very likely. Most of the time pumps fail because they begin to leak.
Other more likely reasons for your situation:
a too loose fan belt slipping from time to time (press on the belt mid-way between the pulleys and it should deflect about 1/4 inch or so).
low coolant level in the overflow bottle may mean low level in the system, which uncovers the thermostat pellet so it fails to open reliably.
air trapped in the system due to improper refill procedure (particularly for 2.2 and 2.5L engine of the '80's and early 90's cars)
exhaust gas in the system due to head gasket leak (are you losing coolant slowly, white smoke in excess from exhaust pipe?)
is it very cold outside and you are running the heater on high (may cause temporary too low a temp in the system, but wouldn't cause it to swing to high so this may not apply)
If none of these apply, then the loose impeller may be the case, but I doubt that.
Write back with any observations/questions and tell me what engine and year of car you have. Also what is the history of the problem: when did you first notice it, any associated service at that time?
Roland