Working on a 1992 Chevy Lumina APV. 3.1 L engine
The engine was experiencing
several problems which have been repaired....but still running hot (not
overheating, just running hotter than normal).
Engine Temperature is 207.3 degrees (OBD1 tester). Electric Fan
does cycle on and off. A radiator thermometer shows antifree temperature
to be around 210 or so.
But, with the engine running and at 200 plus degrees, the system
should be pressurized...but it is not. I can remove the radiator cap
without having the coolent spurt all over. And the upper and
lower radiator hoses...are hot but can easily be collapsed.
When thermostat opens and water begins to flow I get even
heat over the surface of the radiator.
Cooling System Tester showed the cooling system holding
15 pounds pressure steady for over 30 minutes without losing anything.
Also no leaks, or signs of leaks. Radiator Cap tested okay using
tester but I swapped in a new one anyway. No change
The water pump was replaced about a year ago. Thermostat
was replaced (tested before replacement). Radiator is full of
coolent. (about a 50% mixture using an antifreeze tester.
Is the system failing to pressurize during operation indicative of a failing
pump??? Water pump is not leaking. No bearing noise (far as i can tell).
Is the troubleshooting technique okay....what am I overlooking ???
Thanks in advance for your help.