Cooling system not up to temp

160,230 MILES • 6 CYL • 2WD • AUTOMATIC
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MATTHEW FOSTER
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  • 2 POSTS
I have a 3.9L V6,160K miles.Cooling system never heats up to mid range temp value on dash indicator.Outside air temp less than 40f most days.Replaced thermostat & antifreeze, better but still only 1/3 temp range on dash indicator.Water pump was replaced at 80K miles prior.Historicly the truck always takes a long time to heat up.Water pump bad? internal hose collapsed? clogged cooling loop? Engine runs perfect with 18-20 MPG. Pressure test cooling loop?
what should the correct temp be? 160f? and what pressure? 14.7PSIG?
Puzzeled..
Jan 30, 2011 at 6:37 PM
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CARADIODOC
  • ✓Experienced Mechanic
  • 34,397 POSTS
The gauge reading isn't important. What's important is whether it's reaching the proper temperature. You can measure it with a thermometer, but a more accurate way is to read it on the live sensor data with a scanner. It should reach near 200 degrees. The gauge and the Engine Computer use different temperature sensors, and the computer's sensor is the important one.

The dash gauge on my '88 Grand Caravan barely reaches quarter scale but the heater will roast you out. If your heater is working properly, you might try a new sending unit, (single wire) for the gauge even though they rarely fail.

caradiodoc
Jan 30, 2011 at 10:56 PM
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