I have a 97 Outback Legacy with 280,000 miles. It has suddenly started overheating now that I'm using my AC. Meaning with the car just parked in the driveway running the AC it overheats in about 15 Min's.

 

Thats with both electric fans running full on.

 

How do I determine if it the water pump or the Radiator or could it be something else.

Edited June 24, 201015 yr by nuteeter

97 EJ25 has notorious head gasket issues.

 

of course you'd like to rule out other possibilities. are you sure it only does it with the A/C on? if that's the case then i'd suspect your radiator is plugged up, quite common with age.

 

when it overheats - does it have hot air...guess that's hard to tell if the a/c is running and it's 90 degrees outside!

 

if you have a temp gun, hit the radiator and look for cool spots. feel the upper and lower radiator hoses - is one hot and the other cool?

 

any black gunk or bubbles after shutting off the car in the overflow tank?

 

any history or maintenance - tbelt, water pump, thermostat, etc?

My Forester was just doing the same thing only intermittently.

Turned out to be the thermostat. (my radiator is already new).

Changed thermostat,both hoses (were the originals),new coolant with some Wetter water and problem solved.

+1 for thermostat. Make sure you get a Subaru T-stat (Need the Jiggle Valve!) Good time to replace upper and lower hoses.. keep engine running and air bleeder screw cracked open when you re-fill the coolant to eliminate air bubbles! (Air bubbles can cause intermittent over-heating!)

I have a 97 Outback Legacy with 280,000 miles. It has suddenly started overheating now that I'm using my AC. Meaning with the car just parked in the driveway running the AC it overheats in about 15 Min's.

 

Thats with both electric fans running full on.

 

How do I determine if it the water pump or the Radiator or could it be something else.

 

I think it's a testament to Subaru durability that you could idle the car with 280k miles with AC on for 15 minutes and wonder if somethings wrong.