2001 Subaru Legacy Flucuations in Engine temp w/ AC on

2001 SUBARU LEGACY
73,000 MILES • 4 CYL • AWD • AUTOMATIC
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JERRYPA127
  • MEMBER
  • 1 POST
On very hot days, my Legacy engine temp often runs very hot while running the AC, particularly during stop and go driving. On the highway, I notice the temp rise on long hills (when the RPMs are at ther highest). When the engine temp gets high, I turn off the AC and the engine goes back to a steady-state temp. I checked the two radiator fans and found them both running (though I'm not sure they are running at peak efficiency). Coolant in the radiator is full and relatively fresh. Is something (relays/module, fan motors) wearing out or has a specific component failed?
Jun 11, 2008 at 2:20 PM
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KHLOW2008
  • CAR REPAIR CONTRIBUTOR
  • 41,814 POSTS
Hi JerryPA127,

At high rpm when engine overheats, it points to inefficient cooling. Possible causes

1. Radiator clogged.

2. Water pump weak.

3. Thermostat not opening fully.

4. Fans weak or wrongly installed.

5. Partially clogged water passage.
Jun 18, 2008 at 11:00 AM
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