When it happens, get out and listen for the electric radiator fan
(engine on, in park, ebrake on, etc etc). Maybe park with the engine
running and pull the hood if you're unsure.

If the fan is not coming on, turn on the AC and see if the fan comes
on.

If no fan at all, fan fuse or bad fan.

If it works with the AC on but not otherwise, its the fan temp sensor
(wherever that is) or the connection to the sensor.

BTW, if the fan only works with the AC on, go ahead and run the AC
when the temp climbs, it'll likely come right down.

Dave

Hi there:

I have an ’06 Subaru Outback 3.0 sedan with 35,000 miles. The engine
temp. spikes close to red zone when stopping after highway driving OR
when caught in stop-and-go highway traffic.

Once vehicle resumes moving, the temp. gauge slowly drifts back down
again.

This started happening earlier in the summer, and increased in
frequency last week.

When this happens, the overflow tank is boiling with coolant.

Car has consumed several quarts of coolant since start of summer with
no visible leak. This has also increased in frequency—Overflow tank
was full on Thursday 7/17, but drained empty by Sunday 7/20.

Brought it into the dealer today and got the expected “can’t reproduce
the problem.” They are keeping it overnight to try again tomorrow.

In the meantime, I have searched online and noticed four separate
technical service bulletins pertaining to cooling system issues.

Can anyone offer some insight? I am aware that dealers tend to get
prickly when a customer starts spouting off about TSB’s, and I want to
be well informed before I ask the service manager about specific
TSB’s.

Thanks,

Tim