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Check your radiator cap Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Mon, 18 Apr 2005 08:02:44
In Reply to: 99 saab 9-5 overheating in mild warm temperature, robert, Sun, 17 Apr 2005 18:35:09 Members do not see ads below this line. - Help Keep This Site Online - Signup |
The fact that coolant is spewing out of the radiator cap tells me that it isn't holding pressure. Yes, it is designed to release pressure in an overheat situation. But the system is normally pressurized. Coolant under pressure has a higher boiling point - typically 12-15 degrees C (20-27 deg F). It is the cap's job to control that pressure. If the cap is not holding pressure, the boiling point you can boil over without actually overheating.
I'd replace my coolant overflow cap first. They do fail, and it's not very expensive.
If you've got the 2.3L 4 cylinder, the coolant sensor is in the side of the block, just above where the transmission meets. This sensor provides all the information on coolant temperature, both for the temp gauge, Engine control to determine if the engine is warmed up, and for the fans. Note that the temp shown on the temperature gauge isn't a direct reading of the temperature sensor. The control unit adjusts the reading to the gauge. This is because in older cars (older 9000), temp gauge fluctuations made drivers worry and caused lots of service calls for cars 'running hot.' So the ECU adjusts the temp gauge reading. It knows that if you're sitting and idling, the temperature will be higher. So it show the gauge as normal, because that's normal operation. If you are overheating, the temp gauge will go up to the red.
As to the water pump, it is a metal impeller like every other car that I know of. Water pumps almost never fail by not pumping efficiently. The 99% most common fault is for the seal at the bearing to leak, and you get a drip. This in no way impacts cooling capability, not unless you leak the car out of coolant.
I'd check the cap first.
posted by 192.249....
, Mon, 18 Apr 2005 08:02:44 <-- Viewing This Message
, Mon, 18 Apr 2005 07:52:24
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