My Subie's temp guage needle is usually at about 1/2 way up the guage. With the onset of summer & hotter temps, when I run the A/C, the needle has been reaching about 1/4" below the top of the white line of the guage, just before it goes into the red. Before killing the ignition this afternoon, I was shutting down some electrical accessories & I noticed that when I turned off the A/C fan, the needle dropped very slightly. I usually run with the headlights so I flipped them off & noticed the needle instantly dropped slightly again. When I turn them back on, the needle instantly jumps up slightly again. I can't believe that the electrical accessories have an instantaneous affect like this on the temp so I must have some kind of electrical feedback or something. Has anyone heard of this or noticed a similar situation with their Subie? I am worried about the hotter temp & have tried all the tricks to keep the temp down, except the dual core radiator. Prolly my next step. Thanks!

'Bout the onliest thing I can think on, would be a poor ground for the dash unit. This would cause some grounding of the circuits, through other gauges on the dash, including the dash lights themselves. Not sure where the ground wire for the dash is landed, but I have 2 dashes (complete) out in the garage. I can look tommorrow and see where they are grounded. But, they are from an '82 and '86, so it may be in different spot.

 

As to temp, sounds about normal. A/C will cause the engine to run hotter, due to the air off from the evap coil being hotter, and not asorbing much heat from the radiator. And yes, a 2-core would be a wise investment.

I've had the same problem with my wagon. I added a couple extra grounds under the hood from the battery to the body and from the motor to the body.. Problem solved.

 

Soobs like grounds

Got the same prob with mine, just need to get off my arse and add some grounds