Volvo: Cooling System, coolant leaks, jury rig

Question
1992 940 Sedan, 114k miles, owned for only 500 miles.

Jimmy,

I drove without incident through 45 minutes of city traffic and paused, where I let the vehicle idle for ten minutes.  Within one block of resuming the radiator blew.  The ambient temperature that day was 50 degrees fahrenheit The in-dash temperature gauge does work and I limped the vehicle home by driving/cooling.  No problem replacing the radiator (I'm not new to Volvos), but am wondering how to troubleshoot the initial problem that caused the overheat.  Waterpump?  Need advice.  Thermostat?  I cannot quite recall the jury rig thermostat test, either way, they're cheap and since the system is drained I may as well replace it.  Cooling fan?  This is where it gets grey.  My previous experience with Volvos predates the electric fan.  I have never seen nor heard it (as you can hear it after shut down in other make cars), but I have not made a concerted effort to determine if it works.

How should I proceed to diagnose and correct the root problem that caused the overheat?

Thank you,
James Peck

Answer
Hello James! It is difficult to tell you what caused the overheating without seeing the car. Are there any coolant leaks? Does the electric fan turn on? I would check thes items and also replace the thermostat. Also, I would fix the temp guage. It is very important that it works correctly or you may overheat without knowing it.

Jimmy