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2002 Outback Wagon 2.5
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Discussion Starter #1
I have a 2002 OBW with nearly 153k miles on it. The previous owner had a shop replace the head gaskets at 115k in May 2013. Water pump, thermostat and timing belt were replaced at that time too. I do not know what brand gaskets, thermostat or coolant were used.

On my way into work today, I noticed the temp gauge was climbing above normal while in stop-and-go traffic. (I was commuting into Chicago from the burbs, so there was a LOT of stop-and-go once in the city). The temp would climb while stopped or idling along and would drop when traffic was moving. It did reach the red zone a couple of times. Revving the engine to around 1500 rpm while stopped would bring the temp down, and the gauge would move fairly quickly after a few seconds.

When I arrived at work, I revved the engine to 1500 rpm while parked and watched the temp gauge. It dropped from the red zone to to just above the first line not adjacent to red. What was interesting is that it would climb again after about 30 seconds while maintaining 1500 rpm, stopping just before red and then dropping again after 30-40 seconds.

On my way home from work, the temp gauge indicated normal for the first 10-15 minutes and then began to climb while crawling in traffic. Again, revving the engine a bit or when traffic was moving above, say, 15 mph, and the temp would come down. The temp needle was slightly above normal (horizontal instead of slightly below that) at highway speeds and maintained that temp for 15 miles. The temp would rise while coasting, though it would take several seconds for that to happen. The temp would rise while at stop lights on the local streets and drop again when moving. It didn;t hit the red zone during this time.

Once I got home, I noticed the radiator was not at all warm. The upper hose was hot. The lower hose was warm, but not as much as the upper. I let the engine cool for about 1.5 hours and went back out to troubleshoot.

At this point, the upper hose felt empty when squeezing it, while the lower hose felt like it had coolant in it. I pulled the radiator cap and did not see any coolant at the neck aside from some residual coolant. The level in the overflow was well above H. It appeared to be murky grey and smelled a bit like differential lube. Not at all like coolant.

I started the car and let it idle. The engine warmed and maintained normal temp for about 10 minutes, after which the temp climbed, though it didn't reach the red. At this point I checked the hoses again, and this time the top hose was hot and felt solid and looked like it was bulging. The bottom hose felt normal. Pretty warm and felt like it had coolant in it, though it wasn't solid like the upper hose. The radiator was cool to the touch.

A couple of things to note:

-Both radiator fans appeared to be working normally and ran during the elevated temps.
-I did not see any bubbles in the overflow tank while the engine was running, and I did not smell exhaust in there.
-I did not see any signs of coolant on the oil dipstick.
-The last time I was under the car was when I changed the oil a month and 3000 miles ago, and I did not see any leaks.

Tomorrow I plan to stop by the Subaru dealer and pick up a new thermostat, radiator cap, coolant and conditioner and swap them all out. The odor in the coolant is a concern, but I'm hoping it's just residual from when the gaskets were done. (fingers crossed)

Is there anything else I should be checking?
 

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03 H6 OBW & 06 WRX Sportwagon
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17,617 Posts
sounds like a plan

never trust the level in the overflow tank , always check inside the radiator.

in what part of the country are you located?
 

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On the Super Mod Squad
2002 Pair: 3.0 VDC Wag & 2.5 Limited Sedan
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26,193 Posts
I would NOT buy expensive subaru green or blue coolant for this car. (some dealers don't even stock the green anymore).

my own cars have regular prestone green with distilled water with the coolant conditioner. and a car such as yours that you maybe repeat draining and replacing coolant in the near future will get expensive fast. (hopefully you always have a couple clean basins/ jugs handy).

great you are buying a OEM stat/ OEM rad cap though.


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you might use a hand held pistol style thermometer looking for hotspots on the radiator, and/ or pull it off and flush it with a garden hose.

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if in the end you need a new radiator. CSF makes some great ones, and they accept the OEM subaru cap.
(easy/ cheap to buy from summit, amazon etc too) can't easily go from a H4 to a H6 size,...people have asked that here in the recent past.

CSF Radiators - CSF Radiators
 

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2002 Outback Wagon 2.5
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35 Posts
Discussion Starter #4
Thanks for the tips. I'll report back with the results.

1Lucky Texan - I'm in the suburbs of Chicago.
 

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2001 Outback 5 speed, 2000 Outback Automatic, 2002 Legacy Wagon Automatic. All 2.5L
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269 Posts
In the 2001 OB i bought brand new I made the mistake of using a non subaru thermostat after the HG/timing belt/water pump job. Only need to learn that lesson once. I ran Evans waterless coolant at 0 PSI in that car for about 70K miles before selling the car (i blew out my shoulder & couldnt shift for 8 months). Never had an issue with the Evans coolant other than its cost.
 

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2002 Outback Wagon 2.5
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35 Posts
Discussion Starter #6
Apologies for the delayed response.

Last Thursday, as I was picking up my tools and supplies to swap the thermostat, I thought of an overheating issue I had with a motorcycle many years ago. In that case, a bad radiator cap was allowing coolant to flow into the overflow reservoir, effectively draining the system and causing it to overheat.

Seeing that the overflow reservoir in my Outback was well above full, I figured I'd check how low the coolant level in the radiator was by adding some coolant I had on hand. To my surprise, it took on 1.5-2 quarts! I buttoned everything up, stopped at Wally World for new Prestone and distilled water and proceeded to drive the 20 miles to my GF's house (I don't have a garage) to swap the thermostat. Needless to say, the engine temp held at normal the whole trip.

The swap went well. The thermostat I replaced was an aftermarket piece, so despite the car running fine, I'm glad to get that out before it caused any issues. The old coolant was well used up, and it appeared that coolant conditioner had been used at some point as there were several tiny, orange/beige flecks in the coolant. The overflow reservoir had a big glob of a putty-like substance at the bottom.

With the front of the car up on jack stands, I filled up the motor through the upper radiator hose, and then filled the radiator and overflow reservoir. I followed the air-purging procedure in the service manual, and then added maybe another pint or so to the radiator. All told, the car took around 5-6 quarts of coolant. Temp was fine driving home, and the interior heat worked great. After letting the car cool down for a few hours, it took maybe another half pint of coolant. I'll be keeping an eye on the level over the next week or so.

Speaking of coolant conditioner, the dealerships around near me don't stock it, with one parts guy saying their service department no longer does coolant flushes. So, I'm running without conditioner for the time being. I'm thinking I'll change the coolant again in the spring and add the conditioner at that time.

Thanks again for your advice!
 

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