Water tep gage reads low

[BLRobertson]

The 99 my step-daughter bought with 151k temp gage runs at about 160 when warmed up. While flushing the radiator I replaced the thermostat with no change to the gage reading. Are these gages known to be this in accurate. My mother-inlaw has a 98 Astro-Van with the same problem. Also if replacing the gage is necessary it appears to be part of a cluster, any ideas about the cost. Thanks

[roadrunner2]

Originally Posted by BLRobertson

The 99 my step-daughter bought with 151k temp gage runs at about 160 when warmed up. While flushing the radiator I replaced the thermostat with no change to the gage reading. Are these gages known to be this in accurate. My mother-inlaw has a 98 Astro-Van with the same problem. Also if replacing the gage is necessary it appears to be part of a cluster, any ideas about the cost. Thanks

I don't think there is anything wrong with the gauges.

When I bought my (since sold) '00 Olds Silo used, the temp gauge read low as well.

I pulled the t-stat out and found a 180 stat. I replaced it with a 195 and then it showed a proper reading.

With a 160 or a 180 deg stat, (UNLESS otherwise specifically recommended) the engine runs cool and will burn more fuel and emit more emissions than normal for that engine.

[BLRobertson]

RR2, I dug the old thermostat out and it's a 195. I don't remember looking at the new one so I called my parts store and verified what they sold me should be a 195. I'm trying to shop for a scanner that includes live data but haven't decided where to drop the bucks for one. I've got a GM factory manual which refers to a Scan Tool. Does anybody now if this is a brand name or a generic reference to whatever scanner you have? Anyway shouldn't a live data scanner show the ECT reading to determine my actual water temp. When I watch the gage as it warms up I can see the needle pull back slightly as the thermostat opens but this happens like I said near the 160 mark of the temp gage.

[driver540]

Look into finding a raytac gun. It is a laser type temperature reading tool. If you find the thermostat housing is 195 and gauge is 160, then your coolant temp sensor may be bad. It can give a false reading. What temp does the cooling fans come on?

[BLRobertson]

driver540-Got a chance to watch for the cooling fans coming on and looks like the passenger side fan came on about 218 and went off at 180. The increments on the gage don't appear to be a steady progression across the gage but that's my best guess. The driver side fan never came on. I turned on the A/C and the passenger side only was running. Haven't found any of my buddies with a raytac gun so I don't know what thermostat housing temp is yet.

[BLRobertson]

I guess I'll try the temp sensor, it shouldn't be too much. The fan is shorted to ground and had blown the 40 amp fuse (should have been 30 amp) the previous owner tried. I dug out 5 rocks the size of golf balls that had lodge inside the shroud and the fan was dragging to the point of barely turning by hand.